1
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Casotto A, Rukin PS, Fresch E, Prezzi D, Freddi S, Sangaletti L, Rozzi CA, Collini E, Pagliara S. Coherent Vibrations Promote Charge-Transfer across a Graphene-Based Interface. J Am Chem Soc 2024. [PMID: 38767025 DOI: 10.1021/jacs.3c12705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Discerning the impact of the coherent motion of the nuclei on the timing and efficiency of charge transfer at the donor-acceptor interface is essential for designing performance-enhanced optoelectronic devices. Here, we employ an experimental approach using photocurrent detection in coherent multidimensional spectroscopy to excite a donor aromatic macrocycle and collect the charge transferred to a 2D acceptor layer. For this purpose, we prepared a cobalt phthalocyanine-graphene (CoPc-Gr) interface. Unlike blends, the well-ordered architecture achieved through the physical separation of the two layers allows us to unambiguously collect the electrical signal from graphene alone and associate it with a microscopic understanding of the whole process. The CoPc-Gr interface exhibits an ultrafast electron-transfer signal, stemming from an interlayer mechanism. Remarkably, the signal presents an oscillating time evolution modulated by coherent vibrations originating from the laser-excited CoPc states. By performing Fourier analysis on the beatings and correlating it with the Raman features, along with a comprehensive first-principles characterization of the vibrational coupling in the CoPc excited states, we successfully identify both the orbitals and molecular vibrations that promote the charge transfer at the interface.
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Affiliation(s)
- Andrea Casotto
- I-LAMP and Department of Mathematics and Physics, Università Cattolica del Sacro Cuore, via della Garzetta 48, 25133 Brescia, Italy
- Radiation Laboratory and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Pavel S Rukin
- Istituto Nanoscienze─Consiglio Nazionale delle Ricerche (CNR-NANO), via Campi 213/A, 41125 Modena, Italy
| | - Elisa Fresch
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Deborah Prezzi
- Istituto Nanoscienze─Consiglio Nazionale delle Ricerche (CNR-NANO), via Campi 213/A, 41125 Modena, Italy
| | - Sonia Freddi
- I-LAMP and Department of Mathematics and Physics, Università Cattolica del Sacro Cuore, via della Garzetta 48, 25133 Brescia, Italy
| | - Luigi Sangaletti
- I-LAMP and Department of Mathematics and Physics, Università Cattolica del Sacro Cuore, via della Garzetta 48, 25133 Brescia, Italy
| | - Carlo A Rozzi
- Istituto Nanoscienze─Consiglio Nazionale delle Ricerche (CNR-NANO), via Campi 213/A, 41125 Modena, Italy
| | - Elisabetta Collini
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Stefania Pagliara
- I-LAMP and Department of Mathematics and Physics, Università Cattolica del Sacro Cuore, via della Garzetta 48, 25133 Brescia, Italy
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2
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Rasool S, Yeop J, An NG, Kim JW, Kim JY. Role of Charge-Carrier Dynamics Toward the Fabrication of Efficient Air-Processed Organic Solar Cells. SMALL METHODS 2024; 8:e2300578. [PMID: 37649231 DOI: 10.1002/smtd.202300578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 08/10/2023] [Indexed: 09/01/2023]
Abstract
Over the past couple of decades, immense research has been carried out to understand the photo-physics of an organic solar cell (OSC) that is important to enhance its efficiency and stability. Since OSCs undergoes complex photophysical phenomenon, studying these factors has led to designing new materials and implementing new strategies to improve efficiency in OSCs. In this regard, the invention of the non-fullerene acceptorshas greatly revolutionized the understanding of the fundamental processes occurring in OSCs. However, such vital fundamental research from device physics perspectives is carried out on glovebox (GB) processed OSCs and there is a scarcity of research on air-processed (AP) OSCs. This review will focus on charge carrier dynamics such as exciton diffusion, exciton dissociation, charge-transfer states, significance of highest occupied molecular orbital-offsets, and hole-transfer efficiencies of GB-OSCs and compare them with the available data from the AP-OSCs. Finally, key requirements for the fabrication of efficient AP-OSCs will be presented from a charge-carrier dynamics perspective. The key aspects from the charge-carrier dynamics view to fabricate efficient OSCs either from GB or air are provided.
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Affiliation(s)
- Shafket Rasool
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Jiwoo Yeop
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Na Gyeong An
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
- Department of Chemical and Biological Engineering, Monash University, Victoria, 3800, Australia
- Commonwealth Scientific and Industrial Research Organization (CSIRO) Manufacturing, Clayton, Victoria, 3168, Australia
| | - Jae Won Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Jin Young Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
- Graduate School of Carbon Neutrality, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
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3
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Jia X, Soprani L, Londi G, Hosseini SM, Talnack F, Mannsfeld S, Shoaee S, Neher D, Reineke S, Muccioli L, D'Avino G, Vandewal K, Beljonne D, Spoltore D. Molecularly induced order promotes charge separation through delocalized charge-transfer states at donor-acceptor heterojunctions. MATERIALS HORIZONS 2024; 11:173-183. [PMID: 37915305 DOI: 10.1039/d3mh00526g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
The energetic landscape at the interface between electron donating and accepting molecular materials favors efficient conversion of intermolecular charge-transfer (CT) states into free charge carriers (FCC) in high-performance organic solar cells. Here, we elucidate how interfacial energetics, charge generation and radiative recombination are affected by molecular arrangement. We experimentally determine the CT dissociation properties of a series of model, small molecule donor-acceptor blends, where the used acceptors (B2PYMPM, B3PYMPM and B4PYMPM) differ only in the nitrogen position of their lateral pyridine rings. We find that the formation of an ordered, face-on molecular packing in B4PYMPM is beneficial to efficient, field-independent charge separation, leading to fill factors above 70% in photovoltaic devices. This is rationalized by a comprehensive computational protocol showing that, compared to the more amorphous and isotropically oriented B2PYMPM, the higher structural order of B4PYMPM molecules leads to more delocalized CT states. Furthermore, we find no correlation between the quantum efficiency of FCC radiative recombination and the bound or unbound nature of the CT states. This work highlights the importance of structural ordering at donor-acceptor interfaces for efficient FCC generation and shows that less bound CT states do not preclude efficient radiative recombination.
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Affiliation(s)
- Xiangkun Jia
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, 01187 Dresden, Germany
| | - Lorenzo Soprani
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, 40136 Bologna, Italy
| | - Giacomo Londi
- Laboratory for Chemistry of Novel Materials, University of Mons, B-7000 Mons, Belgium.
| | - Seyed Mehrdad Hosseini
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Felix Talnack
- Center for Advancing Electronics Dresden (cfaed) and Faculty of Electrical and Computer Engineering, Technische Universität Dresden, 01062 Dresden, Germany
| | - Stefan Mannsfeld
- Center for Advancing Electronics Dresden (cfaed) and Faculty of Electrical and Computer Engineering, Technische Universität Dresden, 01062 Dresden, Germany
| | - Safa Shoaee
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Dieter Neher
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Sebastian Reineke
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, 01187 Dresden, Germany
| | - Luca Muccioli
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, 40136 Bologna, Italy
| | - Gabriele D'Avino
- Grenoble Alpes University, CNRS, Grenoble INP, Institut Néel, 25 rue des Martyrs, 38042 Grenoble, France
| | - Koen Vandewal
- Institute for Materials Research (IMO-IMOMEC), Hasselt University, Wetenschapspark 1, 3590 Diepenbeek, Belgium.
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons, B-7000 Mons, Belgium.
| | - Donato Spoltore
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, 01187 Dresden, Germany
- Institute for Materials Research (IMO-IMOMEC), Hasselt University, Wetenschapspark 1, 3590 Diepenbeek, Belgium.
- Department of Mathematical, Physical and Computer Sciences, University of Parma, V.le delle Scienze 7/A, 43124 Parma, Italy.
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4
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Fujita T, Hoshi T. Ab Initio Study of Charge Separation Dynamics and Pump-Probe Spectroscopy in the P3HT/PCBM Blend. J Phys Chem B 2023; 127:7615-7623. [PMID: 37639551 DOI: 10.1021/acs.jpcb.3c02458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
We develop a bottom-up computational method for excited-state dynamics and time-resolved spectroscopy signals in molecular aggregates, on the basis of ab initio excited-state calculations. As an application, we consider the charge separation dynamics and pump-probe spectroscopy in the amorphous P3HT/PCBM blend. To simulate quantum dynamics and time-resolved spectroscopy, the model Hamiltonian for single-excitation and double-excitation manifolds was derived on the basis of fragment-based excited-state calculations within the GW approximation and the Bethe-Salpeter equation. After elucidating the energetics of the electron-hole separation and examining linear absorption spectrum, we investigated the quantum dynamics of exciton and charge carriers in comparison with the pump-probe transient absorption spectra. In particular, we introduced the pump-probe excited-state absorption (ESA) anisotropy as a spectroscopic signature of charge carrier dynamics after exciton dissociation. We found that the charge separation dynamics can be probed by the pump-probe ESA anisotropy dynamics after charge-transfer excitations. The present study provides the fundamental information for understanding the experimental spectroscopy signals, by elucidating the relationship between the excited states, the exciton and charge carrier dynamics, and time-resolved spectroscopy.
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Affiliation(s)
- Takatoshi Fujita
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Takeo Hoshi
- Department of Mechanical and Physical Engineering, Faculty of Engineering, Tottori University, Tottori-shi 680-8552, Tottori, Japan
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5
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Liu Q, Vandewal K. Understanding and Suppressing Non-Radiative Recombination Losses in Non-Fullerene Organic Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2302452. [PMID: 37201949 DOI: 10.1002/adma.202302452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/26/2023] [Indexed: 05/20/2023]
Abstract
Organic solar cells benefit from non-fullerene acceptors (NFA) due to their high absorption coefficients, tunable frontier energy levels, and optical gaps, as well as their relatively high luminescence quantum efficiencies as compared to fullerenes. Those merits result in high yields of charge generation at a low or negligible energetic offset at the donor/NFA heterojunction, with efficiencies over 19% achieved for single-junction devices. Pushing this value significantly over 20% requires an increase in open-circuit voltage, which is currently still well below the thermodynamic limit. This can only be achieved by reducing non-radiative recombination, and hereby increasing the electroluminescence quantum efficiency of the photo-active layer. Here, current understanding of the origin of non-radiative decay, as well as an accurate quantification of the associated voltage losses are summarized. Promising strategies for suppressing these losses are highlighted, with focus on new material design, optimization of donor-acceptor combination, and blend morphology. This review aims at guiding researchers in their quest to find future solar harvesting donor-acceptor blends, which combine a high yield of exciton dissociation with a high yield of radiative free carrier recombination and low voltage losses, hereby closing the efficiency gap with inorganic and perovskite photovoltaics.
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Affiliation(s)
- Quan Liu
- Hasselt University, IMOMEC, Wetenschapspark 1, Diepenbeek, 3590, Belgium
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Koen Vandewal
- Hasselt University, IMOMEC, Wetenschapspark 1, Diepenbeek, 3590, Belgium
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6
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Sahoo SR, Patterson CH. Spectroscopic Identification of the Charge Transfer State in Thiophene/Fullerene Heterojunctions: Electroabsorption Spectroscopy from GW/BSE Calculations. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:15928-15942. [PMID: 37609383 PMCID: PMC10440814 DOI: 10.1021/acs.jpcc.3c03734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/19/2023] [Indexed: 08/24/2023]
Abstract
Creation of charge transfer (CT) states in bulk heterojunction systems such as C60/polymer blends is an important intermediate step in the creation of carriers in organic photovoltaic systems. CT states generally have small oscillator strengths in linear optical absorption spectroscopy owing to limited spatial overlap of electron and hole wave functions in the CT excited state. Electroabsorption spectroscopy (EA) exploits changes in wave function character of CT states in response to static electric fields to enhance detection of CT states via nonlinear optical absorption spectroscopies. A 4 × 4 model Hamiltonian is used to derive splittings of even and odd Frenkel (FR) excited states and changes in wave function character of CT excited states in an external electric field. These are used to explain why FR and CT states yield EA lineshapes which are first and second derivatives of the linear optical absorption spectrum. The model is applied to ammonia-borane molecules and pairs of molecules with large and small B-N separations and CT or FR excited states. EA spectra are obtained from differences in linear optical absorption spectra in the presence or absence of a static electric field and from perturbative sum over states (SOS) configuration interaction singles χ(2) and χ(3) nonlinear susceptibility calculations. Good agreement is found between finite field (FF) and SOS methods at field strengths similar to those used in EA experiments. EA spectra of three C60/oligothiophene complexes are calculated using the SOS method combined with GW/BSE methods. For these C60/oligothiophene complexes, we find several CT states in a narrow energy range in which charge transfer from the thiophene HOMO level to several closely spaced C60 acceptor levels yields an EA signal around 10% of the signal from oligothiophene.
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7
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Incorporation of a Boron-Nitrogen Covalent Bond Improves the Charge-Transport and Charge-Transfer Characteristics of Organoboron Small-Molecule Acceptors for Organic Solar Cells. Molecules 2023; 28:molecules28020811. [PMID: 36677871 PMCID: PMC9861936 DOI: 10.3390/molecules28020811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
An organoboron small-molecular acceptor (OSMA) MB←N containing a boron-nitrogen coordination bond (B←N) exhibits good light absorption in organic solar cells (OSCs). In this work, based on MB←N, OSMA MB-N, with the incorporation of a boron-nitrogen covalent bond (B-N), was designed. We have systematically investigated the charge-transport properties and interfacial charge-transfer characteristics of MB-N, along with MB←N, using the density functional theory (DFT) and the time-dependent density functional theory (TD-DFT). Theoretical calculations show that MB-N can simultaneously boost the open-circuit voltage (from 0.78 V to 0.85 V) and the short-circuit current due to its high-lying lowest unoccupied molecular orbital and the reduced energy gap. Moreover, its large dipole shortens stacking and greatly enhances electron mobility by up to 5.91 × 10-3 cm2·V-1·s-1. Notably, the excellent interfacial properties of PTB7-Th/MB-N, owing to more charge transfer states generated through the direct excitation process and the intermolecular electric field mechanism, are expected to improve OSCs performance. Together with the excellent properties of MB-N, we demonstrate a new OSMA and develop a new organoboron building block with B-N units. The computations also shed light on the structure-property relationships and provide in-depth theoretical guidance for the application of organoboron photovoltaic materials.
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8
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Natsuda SI, Saito T, Shirouchi R, Imakita K, Tamai Y. Delocalization suppresses nonradiative charge recombination in polymer solar cells. Polym J 2022. [DOI: 10.1038/s41428-022-00685-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Polymers in High-Efficiency Solar Cells: The Latest Reports. Polymers (Basel) 2022; 14:polym14101946. [PMID: 35631829 PMCID: PMC9143377 DOI: 10.3390/polym14101946] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/06/2022] [Accepted: 05/09/2022] [Indexed: 11/16/2022] Open
Abstract
Third-generation solar cells, including dye-sensitized solar cells, bulk-heterojunction solar cells, and perovskite solar cells, are being intensively researched to obtain high efficiencies in converting solar energy into electricity. However, it is also important to note their stability over time and the devices' thermal or operating temperature range. Today's widely used polymeric materials are also used at various stages of the preparation of the complete device-it is worth mentioning that in dye-sensitized solar cells, suitable polymers can be used as flexible substrates counter-electrodes, gel electrolytes, and even dyes. In the case of bulk-heterojunction solar cells, they are used primarily as donor materials; however, there are reports in the literature of their use as acceptors. In perovskite devices, they are used as additives to improve the morphology of the perovskite, mainly as hole transport materials and also as additives to electron transport layers. Polymers, thanks to their numerous advantages, such as the possibility of practically any modification of their chemical structure and thus their physical and chemical properties, are increasingly used in devices that convert solar radiation into electrical energy, which is presented in this paper.
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10
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Madrid-Úsuga D, Ortiz A, Reina JH. Photophysical Properties of BODIPY Derivatives for the Implementation of Organic Solar Cells: A Computational Approach. ACS OMEGA 2022; 7:3963-3977. [PMID: 35155892 PMCID: PMC8829925 DOI: 10.1021/acsomega.1c04598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
Solar cells based on organic compounds are a proven emergent alternative to conventional electrical energy generation. Here, we provide a computational study of power conversion efficiency optimization of boron dipyrromethene (BODIPY) derivatives by means of their associated open-circuit voltage, short-circuit density, and fill factor. In doing so, we compute for the derivatives' geometrical structures, energy levels of frontier molecular orbitals, absorption spectra, light collection efficiencies, and exciton binding energies via density functional theory (DFT) and time-dependent (TD)-DFT calculations. We fully characterize four D-π-A (BODIPY) molecular systems of high efficiency and improved J sc that are well suited for integration into bulk heterojunction (BHJ) organic solar cells as electron-donor materials in the active layer. Our results are twofold: we found that molecular complexes with a structural isoxazoline ring exhibit a higher power conversion efficiency (PCE), a useful result for improving the BHJ current, and, on the other hand, by considering the molecular systems as electron-acceptor materials, with P3HT as the electron donor in the active layer, we found a high PCE compound favorability with a pyrrolidine ring in its structure, in contrast to the molecular systems built with an isoxazoline ring. The theoretical characterization of the electronic properties of the BODIPY derivatives provided here, computed with a combination of ab initio methods and quantum models, can be readily applied to other sets of molecular complexes to hierarchize optimal power conversion efficiency.
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Affiliation(s)
- Duvalier Madrid-Úsuga
- Centre
for Bioinformatics and Photonics—CIBioFi, Universidad del Valle, Calle 13 No. 100-00, Edificio E20 No. 1069, 760032 Cali, Colombia
- Quantum
Technologies, Information and Complexity Group—QuanTIC, Departamento
de Física, Universidad del Valle, 760032 Cali, Colombia
| | - Alejandro Ortiz
- Centre
for Bioinformatics and Photonics—CIBioFi, Universidad del Valle, Calle 13 No. 100-00, Edificio E20 No. 1069, 760032 Cali, Colombia
- Heterocyclic
Compounds Research Group—GICH, Departamento de Química, Universidad del Valle, 760032 Cali, Colombia
| | - John H. Reina
- Centre
for Bioinformatics and Photonics—CIBioFi, Universidad del Valle, Calle 13 No. 100-00, Edificio E20 No. 1069, 760032 Cali, Colombia
- Quantum
Technologies, Information and Complexity Group—QuanTIC, Departamento
de Física, Universidad del Valle, 760032 Cali, Colombia
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11
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Molteni E, Mattioli G, Alippi P, Avaldi L, Bolognesi P, Carlini L, Vismarra F, Wu Y, Varillas RB, Nisoli M, Singh M, Valadan M, Altucci C, Richter R, Sangalli D. A systematic study of the valence electronic structure of cyclo(Gly-Phe), cyclo(Trp-Tyr) and cyclo(Trp-Trp) dipeptides in the gas phase. Phys Chem Chem Phys 2021; 23:26793-26805. [PMID: 34816853 DOI: 10.1039/d1cp04050b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The electronic energy levels of cyclo(glycine-phenylalanine), cyclo(tryptophan-tyrosine) and cyclo(tryptophan-tryptophan) dipeptides are investigated with a joint experimental and theoretical approach. Experimentally, valence photoelectron spectra in the gas phase are measured using VUV radiation. Theoretically, we first obtain low-energy conformers through an automated conformer-rotamer ensemble sampling scheme based on tight-binding simulations. Then, different first principles computational schemes are considered to simulate the spectra: Hartree-Fock (HF), density functional theory (DFT) within the B3LYP approximation, the quasi-particle GW correction, and the quantum-chemistry CCSD method. Theory allows assignment of the main features of the spectra. A discussion on the role of electronic correlation is provided, by comparing computationally cheaper DFT scheme (and GW) results with the accurate CCSD method.
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Affiliation(s)
- Elena Molteni
- Istituto di Struttura della Materia-CNR (ISM-CNR), Area della Ricerca di Roma 1, Via Salaria km 29.300, CP 10, Monterotondo Scalo, Roma, Italy. .,Dipartimento di Fisica, Universita' degli Studi di Milano, via Celoria 16, I-20133 Milano, Italy
| | - Giuseppe Mattioli
- Istituto di Struttura della Materia-CNR (ISM-CNR), Area della Ricerca di Roma 1, Via Salaria km 29.300, CP 10, Monterotondo Scalo, Roma, Italy.
| | - Paola Alippi
- Istituto di Struttura della Materia-CNR (ISM-CNR), Area della Ricerca di Roma 1, Via Salaria km 29.300, CP 10, Monterotondo Scalo, Roma, Italy.
| | - Lorenzo Avaldi
- Istituto di Struttura della Materia-CNR (ISM-CNR), Area della Ricerca di Roma 1, Via Salaria km 29.300, CP 10, Monterotondo Scalo, Roma, Italy.
| | - Paola Bolognesi
- Istituto di Struttura della Materia-CNR (ISM-CNR), Area della Ricerca di Roma 1, Via Salaria km 29.300, CP 10, Monterotondo Scalo, Roma, Italy.
| | - Laura Carlini
- Istituto di Struttura della Materia-CNR (ISM-CNR), Area della Ricerca di Roma 1, Via Salaria km 29.300, CP 10, Monterotondo Scalo, Roma, Italy.
| | - Federico Vismarra
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, Italy.,CNR-Istituto di Fotonica e Nanotecnologie, Piazza Leonardo da Vinci, 32, Milano, Italy
| | - Yingxuan Wu
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, Italy.,CNR-Istituto di Fotonica e Nanotecnologie, Piazza Leonardo da Vinci, 32, Milano, Italy
| | | | - Mauro Nisoli
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, Italy.,CNR-Istituto di Fotonica e Nanotecnologie, Piazza Leonardo da Vinci, 32, Milano, Italy
| | - Manjot Singh
- Dipartimento di Scienze Biomediche Avanzate, Universita' degli Studi di Napoli Federico II, via Pansini 5, I-80131, Napoli, Italy
| | - Mohammadhassan Valadan
- Dipartimento di Scienze Biomediche Avanzate, Universita' degli Studi di Napoli Federico II, via Pansini 5, I-80131, Napoli, Italy.,Istituto Nazionale Fisica Nucleare (INFN), Sezione di Napoli, Napoli, Italy
| | - Carlo Altucci
- Dipartimento di Scienze Biomediche Avanzate, Universita' degli Studi di Napoli Federico II, via Pansini 5, I-80131, Napoli, Italy.,Istituto Nazionale Fisica Nucleare (INFN), Sezione di Napoli, Napoli, Italy
| | - Robert Richter
- Sincrotrone Trieste, Area Science Park, Basovizza, Trieste, Italy
| | - Davide Sangalli
- Istituto di Struttura della Materia-CNR (ISM-CNR), Area della Ricerca di Roma 1, Via Salaria km 29.300, CP 10, Monterotondo Scalo, Roma, Italy. .,Dipartimento di Fisica, Universita' degli Studi di Milano, via Celoria 16, I-20133 Milano, Italy
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12
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Probing molecular orientation at bulk heterojunctions by polarization-selective transient absorption spectroscopy. Sci China Chem 2021. [DOI: 10.1007/s11426-021-1046-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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Schwaiger DM, Lohstroh W, Müller-Buschbaum P. The Influence of the Blend Ratio, Solvent Additive, and Post-production Treatment on the Polymer Dynamics in PTB7:PCBM Blend Films. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dominik M. Schwaiger
- Physik-Department, Technische Universität München, Lehrstuhl für Funktionelle Materialien James-Franck-Straße 1, 85748 Garching, Germany
| | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany
| | - Peter Müller-Buschbaum
- Physik-Department, Technische Universität München, Lehrstuhl für Funktionelle Materialien James-Franck-Straße 1, 85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany
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14
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Park SH, Kwon NY, Kim HJ, Cho E, Kang H, Harit AK, Woo HY, Yoon HJ, Cho MJ, Choi DH. Nonhalogenated Solvent-Processed High-Performance Indoor Photovoltaics Made of New Conjugated Terpolymers with Optimized Monomer Compositions. ACS APPLIED MATERIALS & INTERFACES 2021; 13:13487-13498. [PMID: 33710873 DOI: 10.1021/acsami.0c22946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Conjugated random terpolymers, PJ-25, PJ-50, and PJ-75 were successfully synthesized from three different monomers. Fluorine-substituted benzotriazole (2F-BTA) was incorporated into 4,8-bis(4-chlorothiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene (BDT-T-Cl) and a 1,3-bis(4-(2-ethylhexyl)thiophen-2-yl)-5,7-bis(2-alkyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione (BDD)-based alternating copolymer PM7 as a third monomeric unit. The solubility of the random terpolymers in nonhalogenated solvents increased with the number of 2F-BTA units in PM7. The random terpolymers were mixed with 3,9-bis(2-methylene-((3-(1,1-dicyanomethylene)-6,7-difluoro)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IT-4F) to fabricate organic photovoltaic (OPV) cells. Among the three terpolymers and two related binary copolymers (e.g., PM7 and J52-Cl), outdoor photovoltaic (PV) cells (AM 1.5G) based on the PJ-50:IT-4F blend showed a high power conversion efficiency (PCE) of 11.34%. In addition, PJ-50 was employed as a donor in indoor PV (IPV) cells and was blended with nonfullerene acceptors, which have different absorption ranges. Among them, the PJ-50:IT-4F-based IPV device had the highest PCE of 17.41% with a Jsc of 54.75 μA cm-2 and an FF of 0.77 under 160 μW cm-2 light-emitting diode (LED) light. The terpolymer introduced in this study can be regarded as a promising material for the fabrication of outdoor PV and IPV cells with excellent performance involving the use of an eco-friendly solvent.
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Affiliation(s)
- Su Hong Park
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Na Yeon Kwon
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Hyung Jong Kim
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Eunbin Cho
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Hungu Kang
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Amit Kumar Harit
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Han Young Woo
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Min Ju Cho
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Dong Hoon Choi
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
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15
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Synthesis and Characterization of Benzotriazole-Based Polymer Donors with Good Planarity for Organic Photovoltaics. Macromol Res 2020. [DOI: 10.1007/s13233-020-8124-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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16
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Xu Y, Yao H, Ma L, Hong L, Li J, Liao Q, Zu Y, Wang J, Gao M, Ye L, Hou J. Tuning the Hybridization of Local Exciton and Charge-Transfer States in Highly Efficient Organic Photovoltaic Cells. Angew Chem Int Ed Engl 2020; 59:9004-9010. [PMID: 32153106 DOI: 10.1002/anie.201915030] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Indexed: 11/08/2022]
Abstract
Decreasing the energy loss is one of the most feasible ways to improve the efficiencies of organic photovoltaic (OPV) cells. Recent studies have suggested that non-radiative energy loss ( E non - rad loss ) is the dominant factor that hinders further improvements in state-of-the-art OPV cells. However, there is no rational molecular design strategy for OPV materials with suppressed E non - rad loss . Herein, taking molecular surface electrostatic potential (ESP) as a quantitative parameter, we establish a general relationship between chemical structure and intermolecular interactions. The results reveal that increasing the ESP difference between donor and acceptor will enhance the intermolecular interaction. In the OPV cells, the enhanced intermolecular interaction will increase the charge-transfer (CT) state ratio in its hybridization with the local exciton state to facilitate charge generation, but simultaneously result in a larger E non - rad loss . These results suggest that finely tuning the ESP of OPV materials is a feasible method to further improve the efficiencies of OPV cells.
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Affiliation(s)
- Ye Xu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Huifeng Yao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Lijiao Ma
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Ling Hong
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Jiayao Li
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qing Liao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Yunfei Zu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Jingwen Wang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Mengyuan Gao
- School of Materials Science and Engineering, Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, Tianjin, 300350, P. R. China
| | - Long Ye
- School of Materials Science and Engineering, Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, Tianjin, 300350, P. R. China
| | - Jianhui Hou
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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17
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Xu Y, Yao H, Ma L, Hong L, Li J, Liao Q, Zu Y, Wang J, Gao M, Ye L, Hou J. Tuning the Hybridization of Local Exciton and Charge‐Transfer States in Highly Efficient Organic Photovoltaic Cells. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915030] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ye Xu
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Huifeng Yao
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Lijiao Ma
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Ling Hong
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Jiayao Li
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Qing Liao
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Yunfei Zu
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Jingwen Wang
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Mengyuan Gao
- School of Materials Science and Engineering Tianjin Key Laboratory of Molecular Optoelectronic Science Tianjin University Tianjin 300350 P. R. China
| | - Long Ye
- School of Materials Science and Engineering Tianjin Key Laboratory of Molecular Optoelectronic Science Tianjin University Tianjin 300350 P. R. China
| | - Jianhui Hou
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
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18
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Ma L, Zhang S, Wang J, Xu Y, Hou J. Recent advances in non-fullerene organic solar cells: from lab to fab. Chem Commun (Camb) 2020; 56:14337-14352. [DOI: 10.1039/d0cc05528j] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The key factors for OSC materials toward application mainly include high performance, thickness tolerance, low cost, simple fabrication processing, high stability, and an environmentally-friendly nature.
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Affiliation(s)
- Lijiao Ma
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Polymer Physics and Chemistry
- CAS Research/Education Center for Excellence in Molecular Sciences
- Institute of Chemistry
- Chinese Academy of Sciences
| | - Shaoqing Zhang
- School of Chemistry and Biology Engineering
- University of Science and Technology Beijing
- Beijing 100083
- P. R. China
| | - Jingwen Wang
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Polymer Physics and Chemistry
- CAS Research/Education Center for Excellence in Molecular Sciences
- Institute of Chemistry
- Chinese Academy of Sciences
| | - Ye Xu
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Polymer Physics and Chemistry
- CAS Research/Education Center for Excellence in Molecular Sciences
- Institute of Chemistry
- Chinese Academy of Sciences
| | - Jianhui Hou
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Polymer Physics and Chemistry
- CAS Research/Education Center for Excellence in Molecular Sciences
- Institute of Chemistry
- Chinese Academy of Sciences
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19
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Liang YJ, Zhao ZW, Geng Y, Pan QQ, Gu HY, Zhao L, Zhang M, Wu SX, Su ZM. Can we utilize the higher Frenkel exciton state in biazulene diimides-based non-fullerene acceptors to promote charge separation at the donor/acceptor interface? NEW J CHEM 2020. [DOI: 10.1039/d0nj01245a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The pathway of charge transfer from the Frenkel exciton state of the acceptor to charge transfer states was investigated.
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Affiliation(s)
- Yue-Jian Liang
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- P. R. China
| | - Zhi-Wen Zhao
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- P. R. China
| | - Yun Geng
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- P. R. China
| | - Qing-Qing Pan
- School of Chemistry and Environmental Engineering
- Changchun University of Science and Technology
- Changchun 130028
- P. R. China
| | - Hao-Yu Gu
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- P. R. China
| | - Liang Zhao
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- P. R. China
| | - Min Zhang
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- P. R. China
| | - Shui-Xing Wu
- School of Chemistry and Chemistry Engineering
- Hainan Normal University
- Haikou
- P. R. China
| | - Zhong-Min Su
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- P. R. China
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20
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Rana D, Jovanov V, Wagner V, Materny A, Donfack P. Insights into ultrafast charge-pair dynamics in P3HT:PCBM devices under the influence of static electric fields. RSC Adv 2020; 10:42754-42764. [PMID: 35514888 PMCID: PMC9058153 DOI: 10.1039/d0ra07935a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/16/2020] [Indexed: 12/16/2022] Open
Abstract
Polymer-fullerene blends based on poly(3-hexylthiophene-2,5-diyl) (P3HT) and phenyl-C61-butyric-acid methyl ester (PCBM) have been extensively studied as promising bulk heterojunction materials for organic semiconductor devices with improved performance. In these donor–acceptor systems where the bulk morphology plays a crucial role, the generation and subsequent decay mechanisms of photoexcitation species are still not completely understood. In this work, we use femtosecond transient absorption spectroscopy to investigate P3HT:PCBM diodes under the influence of applied static electric fields in comparison to P3HT:PCBM thin films. At the same time, we try to present a detailed overview about work already done on these donor–acceptor systems. The excited state dynamics obtained at 638 nm from P3HT:PCBM thin films are found to be similar to those observed earlier in neat P3HT films, while those obtained in the P3HT:PCBM devices are affected by field-induced exciton dissociation, resulting not only in comparatively slower decay dynamics, but also in bimolecular deactivation processes. External electric fields are expected to enhance charge generation in the investigated P3HT:PCBM devices by dissociating excitons and loosely bound intermediate species like polaron pairs (PPs) and charge transfer (CT) excitons, which can already dissociate only due to the intrinsic fields at the donor–acceptor interfaces. Our results clearly establish the formation of PP-like transient species different from CT excitons in the P3HT:PCBM devices as a result of a field-induced diffusion-controlled exciton dissociation process. We find that the loosely bound transient species formed in this way also are reduced in part via a bimolecular annihilation process resulting in charge loss in typical donor–acceptor P3HT:PCBM bulk heterojunction semiconductor devices, which is a rather interesting finding important for a better understanding of the performance of these devices. Electric field effects in P3HT:PCBM solar cell result in polaron-pair-like secondary photoexcitation species showing slower and bimolecular decay characteristics.![]()
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Affiliation(s)
- Debkumar Rana
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Vladislav Jovanov
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Veit Wagner
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Arnulf Materny
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Patrice Donfack
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
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21
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Naveed HB, Zhou K, Ma W. Interfacial and Bulk Nanostructures Control Loss of Charges in Organic Solar Cells. Acc Chem Res 2019; 52:2904-2915. [PMID: 31577121 DOI: 10.1021/acs.accounts.9b00331] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Organic solar cells (OSCs) have emerged as one promising sustainable energy resource since the introduction of state-of-the-art bulk heterojunction (BHJ) device structure in early 1990s. Impressively developed molecular design methodologies in the past decade have led researchers toward utilizing more suitable pairs of low (p-type) and high (n-type) electron affinity organic semiconducting materials. Among other attributes, versatile absorption capabilities of these materials highlight their favorable utilization in a single layer BHJ structure. Interaction of these verstile organic materials may lead to explicit interfaces, phase distributions, and crystalline nanostructures. Structural characterization techniques involving soft and hard X-rays have enabled us to measure these morphology parameters quantitatively including their string correlation with photovoltaic (PV) parameters. Favorable processing techniques have been adopted to realize auspicious interfacial areas and charge percolations in bulk toward efficient short circuit current (JSC) and fill factor (FF) values. Collaborative efforts in the fields of chemical structure design of materials, device characterization, and engineering have pushed the power conversion efficiencies (PCEs) of OSCs to 16%. However, the single layer BHJ structure still requires further optimizations for the extension of their PCEs toward the theoretical limit. Maximum utilization of solar energy by organic blend films is the key to match their potential with inorganic/perovskite solar cells. Having comparable JSC and FF values in organic versus inorganic photovoltaic devices, open circuit voltage (VOC) is the only PV parameter limiting the development of OSCs in comparison to their inorganic competitors. This is due to unfavorable competition between rates of charge generation and recombination. Loss of charges during these generation and recombination processes account for the energy loss of the device, ranging from 0.6 to 1.0 V in state-of-the-art OSCs. Highly efficient (14-16%) single layer BHJ devices usually suffer from high energy loss with VOC limited to 0.9 V. Comparatively, devices with reported VOC > 0.9 V suffer from poor JSC and FF values due to unfavorable interfacial ordering and bulk crystalline nanostructures. First part of the Account will address the charge losses during their transfer (interfacial losses) and influential role of interfacial nanostructures in controlling them toward efficient JSC and VOC values. Later, we will discuss losses during exciton diffusion and free charge transport (bulk losses) toward limited charge extraction. We will debate about the role of donor/acceptor nanostructures in correlation with influential photophysics studies to control these losses in small molecule (SM) acceptor based devices. We search for exaggerated crystalline phases of SM acceptor in competition with polymer donor to realize balanced and more efficient charge percolations. These improved diffusion and transport bulk nanostructures will suppress nonradiative (NR) pathways and bulk charge losses toward simultaneous enhancement of FF and VOC values. Favorable interfacial and bulk morphology will drive efficient diffusion, transfer, transport, and extraction of charges in organic blend films. This Account will guide chemists and engineers to optimize chemical structure design and blend film nanostructures toward suppressed energy loss of OSCs.
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Affiliation(s)
- Hafiz Bilal Naveed
- State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, P.R. China
| | - Ke Zhou
- State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, P.R. China
| | - Wei Ma
- State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, P.R. China
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22
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Fujita T, Noguchi Y, Hoshi T. Charge-transfer excited states in the donor/acceptor interface from large-scale GW calculations. J Chem Phys 2019; 151:114109. [PMID: 31542033 DOI: 10.1063/1.5113944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Predicting the charge-transfer (CT) excited states across the donor/acceptor (D/A) interface is essential for understanding the charge photogeneration process in an organic solar cell. Here, we present a fragment-based GW implementation that can be applied to a D/A interface structure and thus enables accurate determination of the CT states. The implementation is based on the fragmentation approximation of the polarization function and the combined GW and Coulomb-hole plus screened exchange approximations for self-energies. The fragment-based GW is demonstrated by application to the pentacene/C60 interface structure containing more than 2000 atoms. The CT excitation energies were estimated from the quasiparticle energies and electron-hole screened Coulomb interactions; the computed energies are in reasonable agreement with experimental estimates from the external quantum efficiency measurements. We highlight the impact of the induced polarization effects on the electron-hole energetics. The proposed fragment-based GW method offers a first-principles tool to compute the quasiparticle energies and electronic excitation energies of organic materials.
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Affiliation(s)
| | - Yoshifumi Noguchi
- Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University, Hamamatsu, Shizuoka 432-8561, Japan
| | - Takeo Hoshi
- Department of Applied Mathematics and Physics, Tottori University, Tottori 680-8550, Japan
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23
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Yu R, Yao H, Cui Y, Hong L, He C, Hou J. Improved Charge Transport and Reduced Nonradiative Energy Loss Enable Over 16% Efficiency in Ternary Polymer Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1902302. [PMID: 31294900 DOI: 10.1002/adma.201902302] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/03/2019] [Indexed: 06/09/2023]
Abstract
Recent advances in the material design and synthesis of nonfullerene acceptors (NFAs) have revealed a new landscape for polymer solar cells (PSCs) and have boosted the power conversion efficiencies (PCEs) to over 15%. Further improvements of the photovoltaic performance are a significant challenge in NFA-PSCs based on binary donor:acceptor blends. In this study, ternary PSCs are fabricated by incorporating a fullerene derivative, PC61 BM, into a combination of a polymer donor (PBDB-TF) and a fused-ring NFA (Y6) and a very high PCE of 16.5% (certified as 16.2%) is recorded. Detailed studies suggest that the loading of PC61 BM into the PBDB-TF:Y6 blend can not only enhance the electron mobility but also can increase the electroluminescence quantum efficiency, leading to balanced charge transport and reduced nonradiative energy losses simultaneously. This work suggests that utilizing the complementary advantages of fullerene and NFAs is a promising way to finely tune the detailed photovoltaic parameters and further improve the PCEs of PSCs.
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Affiliation(s)
- Runnan Yu
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS), Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Huifeng Yao
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS), Beijing, 100190, China
| | - Yong Cui
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS), Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ling Hong
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS), Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chang He
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS), Beijing, 100190, China
| | - Jianhui Hou
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS), Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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24
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Kawashima E, Fujii M, Yamashita K. Entropy promotes charge separation in bulk heterojunction organic photovoltaics. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.111875] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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25
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Hong L, Yao H, Wu Z, Cui Y, Zhang T, Xu Y, Yu R, Liao Q, Gao B, Xian K, Woo HY, Ge Z, Hou J. Eco-Compatible Solvent-Processed Organic Photovoltaic Cells with Over 16% Efficiency. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1903441. [PMID: 31392768 DOI: 10.1002/adma.201903441] [Citation(s) in RCA: 140] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/11/2019] [Indexed: 05/20/2023]
Abstract
Recent advances in nonfullerene acceptors (NFAs) have enabled the rapid increase in power conversion efficiencies (PCEs) of organic photovoltaic (OPV) cells. However, this progress is achieved using highly toxic solvents, which are not suitable for the scalable large-area processing method, becoming one of the biggest factors hindering the mass production and commercial applications of OPVs. Therefore, it is of great importance to get good eco-compatible processability when designing efficient OPV materials. Here, to achieve high efficiency and good processability of the NFAs in eco-compatible solvents, the flexible alkyl chains of the highly efficient NFA BTP-4F-8 (also known as Y6) are modified and BTP-4F-12 is synthesized. Combining with the polymer donor PBDB-TF, BTP-4F-12 shows the best PCE of 16.4%. Importantly, when the polymer donor PBDB-TF is replaced by T1 with better solubility, various eco-compatible solvents can be applied to fabricate OPV cells. Finally, over 14% efficiency is obtained with tetrahydrofuran (THF) as the processing solvent for 1.07 cm2 OPV cells by the blade-coating method. These results indicate that the simple modification of the side chain can be used to tune the processability of active layer materials and thus make it more applicable for the mass production with environmentally benign solvents.
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Affiliation(s)
- Ling Hong
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Huifeng Yao
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Ziang Wu
- Department of Chemistry, Korea University, Seoul, 136-701, Republic of Korea
| | - Yong Cui
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Tao Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Ye Xu
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Runnan Yu
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qing Liao
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Bowei Gao
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Kaihu Xian
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Han Young Woo
- Department of Chemistry, Korea University, Seoul, 136-701, Republic of Korea
| | - Ziyi Ge
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Jianhui Hou
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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26
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Hong L, Yao H, Yu R, Xu Y, Gao B, Ge Z, Hou J. Investigating the Trade-Off between Device Performance and Energy Loss in Nonfullerene Organic Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2019; 11:29124-29131. [PMID: 31331162 DOI: 10.1021/acsami.9b10243] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The large energy loss (Eloss) in organic solar cells (OSCs) relative to those of silicon or inorganic/organic hybrid perovskite solar cells is one of the major factors limiting the power conversion efficiency (PCE) of OSCs. Recently, OSCs based on nonfullerene acceptors (NFAs) have achieved high PCEs at decreased Eloss values. Therefore, the present study investigates the relationship between Eloss and the device performance of NFA-based OSCs. Here, we select two polymer donors (PBDB-T and its fluorinated derivative PBDB-TF) and blend each polymer donor with each of three NFAs (indaceno[1,2-b:5,6-b']dithiophene and 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (IEIC) and its respective fluorinated and chlorinated derivatives IE-4F and IE-4Cl), which provide varied energy-level alignments. The six blends exhibit similar morphologies and charge transport properties but varied Eloss values in OSCs. The results indicate that the charge generation and PCE of the OSCs increase with the increasing Eloss. Accordingly, the PBDB-T:IE-4Cl-based device yields the highest PCE of 11.1% with an Eloss of 0.64 eV, while the PBDB-TF:IEIC-based device provides a significantly decreased PCE of 3.8% with a diminished Eloss of 0.52 eV. These results demonstrate the great importance of finely tuning the energy-level alignments of these types of donor/acceptor systems to achieve the best device performance.
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Affiliation(s)
- Ling Hong
- Ningbo Institute of Materials Technology and Engineering , Chinese Academy of Sciences , Ningbo 315201 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Huifeng Yao
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences , CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS) , Beijing 100190 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Runnan Yu
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences , CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS) , Beijing 100190 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Ye Xu
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences , CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS) , Beijing 100190 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Bowei Gao
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences , CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS) , Beijing 100190 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Ziyi Ge
- Ningbo Institute of Materials Technology and Engineering , Chinese Academy of Sciences , Ningbo 315201 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Jianhui Hou
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences , CAS Research/Education Center for Excellence in Molecular Sciences (BNLMS) , Beijing 100190 , P. R. China
- University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
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Dey S. Recent Progress in Molecular Design of Fused Ring Electron Acceptors for Organic Solar Cells. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1900134. [PMID: 30989808 DOI: 10.1002/smll.201900134] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/24/2019] [Indexed: 05/20/2023]
Abstract
The quest for sustainable energy sources has led to accelerated growth in research of organic solar cells (OSCs). A solution-processed bulk-heterojunction (BHJ) OSC generally contains a donor and expensive fullerene acceptors (FAs). The last 20 years have been devoted by the OSC community to developing donor materials, specifically low bandgap polymers, to complement FAs in BHJs. The current improvement from ≈2.5% in 2013 to 17.3% in 2018 in OSC performance is primarily credited to novel nonfullerene acceptors (NFA), especially fused ring electron acceptors (FREAs). FREAs offer unique advantages over FAs, like broad absorption of solar radiation, and they can be extensively chemically manipulated to tune optoelectronic and morphological properties. Herein, the current status in FREA-based OSCs is summarized, such as design strategies for both wide and narrow bandgap FREAs for BHJ, all-small-molecule OSCs, semi-transparent OSC, ternary, and tandem solar cells. The photovoltaics parameters for FREAs are summarized and discussed. The focus is on the various FREA structures and their role in optical and morphological tuning. Besides, the advantages and drawbacks of both FAs and NFAs are discussed. Finally, an outlook in the field of FREA-OSCs for future material design and challenges ahead is provided.
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Affiliation(s)
- Somnath Dey
- Department of Chemistry, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar
- Department of Chemistry & Earth Sciences, Qatar University, P.O. Box 2713, Doha, Qatar
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28
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Becker-Koch D, Rivkin B, Paulus F, Xiang H, Dong Y, Chen Z, Bakulin AA, Vaynzof Y. Probing charge transfer states at organic and hybrid internal interfaces by photothermal deflection spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:124001. [PMID: 30572317 DOI: 10.1088/1361-648x/aafa4e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In organic and hybrid photovoltaic devices, the asymmetry required for charge separation necessitates the use of a donor and an acceptor material, resulting in the formation of internal interfaces in the device active layer. While the core objective of these interfaces is to facilitate charge separation, bound states between electrons and holes may form across them, resulting in a loss mechanism that diminishes the performance of the solar cells. These interfacial transitions appear in organic systems as charge transfer (CT) states and as bound charge pairs (BCP) in hybrid systems. Despite being similar, the latter are far less investigated. Herein, we employ photothermal deflection spectroscopy and pump-push-probe experiments in order to determine the characteristics and dynamics of interfacial states in two model systems: an organic P3HT:PCBM and hybrid P3HT:ZnO photovoltaic layer. By controlling the area of the internal interface, we identify CT states between 1.4 eV and 1.8 eV in the organic bulk-heterojunction (BHJ) and BCP between 1.1 eV and 1.4 eV in the hybrid BHJ. The energetic distribution of these states suggests that they not only contribute to losses in photocurrent, but also significantly limit the possible maximum open circuit voltage obtainable from these devices.
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Affiliation(s)
- David Becker-Koch
- Kirchhoff Institut für Physik, Ruprecht-Karls-Universität, Heidelberg, Germany. Centre for Advanced Materials, Ruprecht-Karls-Universität, Heidelberg, Germany
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29
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Ou RX, Lin CH, Guo TF, Wen TC. Improvement in inverted polymer solar cells via 1-benzoyl-2-thiourea as surface modifier on sol-gel ZnO. J Taiwan Inst Chem Eng 2019. [DOI: 10.1016/j.jtice.2018.10.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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30
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Karagöz E, Fiat Varol S, Sayın S, Merdan Z. Electrical characterization of two analogous Schottky contacts produced from N-substituted 1,8-naphthalimide. Phys Chem Chem Phys 2018; 20:30502-30513. [PMID: 30511079 DOI: 10.1039/c8cp04136a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aim of this study was to analyze the interface states (Nss) in pure Al//p-Si/Al, Al/N-F Nft/p-Si/Al and Al/N-T Nft/p-Si/Al Schottky barrier diodes (SBDs). N-Substituted 1,8-naphthalimide thin films were deposited on a p-Si substrate by spin coating and annealed at ∼200 °C for 60 s under an air atmosphere. Al contacts were obtained via reactive magnetron sputtering. The current voltage (I-V) characteristics of the SBDs were measured at room temperature. From the I-V characteristics, the SBDs ideality factor (n) and zero-bias barrier height values (Φb) of 1.27, 1.00, and 1.05 and 0.66 eV, 0.70 eV, and 0.64 eV were observed for the Al//p-Si/Al, Al/N-F Nft/p-Si/Al and Al/N-T Nft/p-Si/Al Schottky barrier diodes, respectively. The interface state density distribution profile (Nss) as a function of (Ess-Ev) was extracted from the forward-bias I-V measurements by considering the effective barrier height and (Φe) and series resistance (Rs) of the Schottky diode. The obtained Nss plot tendency showed that the existence of interface states has no significant effect on the rectifying and capacitance characteristics. The Nss values with the 1,8-naphthalimide layer were lower than that without it. This shows that naphthalimide exhibits a strong contribution by blocking the unwanted states and some traps in the conduction mechanism, which may cause possible cracks or deep paths for carriers to travel along the junction.
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Affiliation(s)
- Emine Karagöz
- Giresun University, Faculty of Engineering, Energy Systems Engineering, 28200, Giresun, Turkey
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31
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Fujita T, Alam MK, Hoshi T. Thousand-atom ab initio calculations of excited states at organic/organic interfaces: toward first-principles investigations of charge photogeneration. Phys Chem Chem Phys 2018; 20:26443-26452. [PMID: 30306163 DOI: 10.1039/c8cp05574b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Predicting electronically excited states across electron-donor/electron acceptor interfaces is essential for understanding the charge photogeneration process in organic solar cells. However, organic solar cells are large and disordered systems, and their excited states cannot be easily accessed by conventional quantum chemistry approaches. Moreover, a large number of excited states must be obtained to fully understand the charge separation mechanism. Recently, we have developed a novel fragment-based excited state method which can efficiently calculate a large number of states in molecular aggregates. In this article, we demonstrate the large-scale excited-state calculations by investigating interfacial charge transfer (ICT) states across the electron-donor/electron acceptor interfaces. As the model systems, we considered the face-on and edge-on configurations of pentacene/C60 bilayer heterojunction structures. These model structures contain approximately 1.8 × 105 atoms, and their local interface regions containing 2000 atoms were treated quantum mechanically, embedded in the electrostatic potentials from the remaining parts. Therefore, the charge delocalization effect, structural disorder, and the resulting heterogeneous electrostatic and polarizable environments were taken into account in the excited-state calculations. The computed energies of the low-lying ICT states are in reasonable agreement with experimental estimates. By comparing the edge-on and face-on configurations of the pentacene/C60 interfaces, we discuss the influence of interfacial morphologies on the energetics and charge delocalization of ICT states. In addition, we present the detailed characterization of excited states and highlight the importance of hybridization effects between pentacene excited states and ICT states. The large-scale ab initio calculations for the interface systems enabled the exploration of the ICT states, leading to first-principles investigation of the charge separation mechanism in organic solar cells.
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Affiliation(s)
- Takatoshi Fujita
- Institute for Molecular Science, Okazaki, Aichi 444-0865, Japan.
| | - Md Khorshed Alam
- Department of Physics, University of Barisal, Barisal-8200, Bangladesh
| | - Takeo Hoshi
- Department of Applied Mathmatics and Physics, Tottori University, Tottori 680-8550, Japan
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32
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Shivanna R, Rajaram S, Narayan KS. Role of Charge-Transfer State in Perylene-Based Organic Solar Cells. ChemistrySelect 2018. [DOI: 10.1002/slct.201801134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ravichandran Shivanna
- Chemistry and Physics of Materials Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore 560064 India
- Optoelectronics Group; Cavendish Laboratory; University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE; U.K
| | - Sridhar Rajaram
- International Centre for Materials Science; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore 560064 India
| | - K. S. Narayan
- Chemistry and Physics of Materials Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore 560064 India
- School of Advanced Materials; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore 560064 India
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33
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Lee H, Park C, Sin DH, Park JH, Cho K. Recent Advances in Morphology Optimization for Organic Photovoltaics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1800453. [PMID: 29921007 DOI: 10.1002/adma.201800453] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 03/12/2018] [Indexed: 06/08/2023]
Abstract
Organic photovoltaics are an important part of a next-generation energy-harvesting technology that uses a practically infinite pollutant-free energy source. They have the advantages of light weight, solution processability, cheap materials, low production cost, and deformability. However, to date, the moderate photovoltaic efficiencies and poor stabilities of organic photovoltaics impede their use as replacements for inorganic photovoltaics. Recent developments in bulk-heterojunction organic photovoltaics mean that they have almost reached the lower efficiency limit for feasible commercialization. In this review article, the recent understanding of the ideal bulk-heterojunction morphology of the photoactive layer for efficient exciton dissociation and charge transport is described, and recent attempts as well as early-stage trials to realize this ideal morphology are discussed systematically from a morphological viewpoint. The various approaches to optimizing morphologies consisting of an interpenetrating bicontinuous network with appropriate domain sizes and mixed regions are categorized, and in each category, the recent trends in the morphology control on the multilength scale are highlighted and discussed in detail. This review article concludes by identifying the remaining challenges for the control of active layer morphologies and by providing perspectives toward real application and commercialization of organic photovoltaics.
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Affiliation(s)
- Hansol Lee
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 37673, South Korea
| | - Chaneui Park
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 37673, South Korea
| | - Dong Hun Sin
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 37673, South Korea
| | - Jong Hwan Park
- Nano Hybrid Technology Research Center, Creative and Fundamental Research Division, Korea Electrotechnology Research Institute (KERI), Changwon, 51543, South Korea
| | - Kilwon Cho
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 37673, South Korea
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34
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Albes T, Gagliardi A. Charge Pair Separation Dynamics in Organic Bulk-Heterojunction Solar Cells. ADVANCED THEORY AND SIMULATIONS 2018. [DOI: 10.1002/adts.201800032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tim Albes
- Department of Electrical and Computer Engineering; Technical University of Munich; Arcisstr. 21 80333 Munich Germany
| | - Alessio Gagliardi
- Department of Electrical and Computer Engineering; Technical University of Munich; Arcisstr. 21 80333 Munich Germany
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35
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Perfetto E, Sangalli D, Marini A, Stefanucci G. Ultrafast Charge Migration in XUV Photoexcited Phenylalanine: A First-Principles Study Based on Real-Time Nonequilibrium Green's Functions. J Phys Chem Lett 2018; 9:1353-1358. [PMID: 29494772 DOI: 10.1021/acs.jpclett.8b00025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The early-stage density oscillations of the electronic charge in molecules irradiated by an attosecond XUV pulse takes place on femto- or subfemtosecond time scales. This ultrafast charge migration process is a central topic in attoscience because it dictates the relaxation pathways of the molecular structure. A predictive quantum theory of ultrafast charge migration should incorporate the atomistic details of the molecule, electronic correlations, and the multitude of ionization channels activated by the broad-bandwidth XUV pulse. We propose a first-principles nonequilibrium Green's function method fulfilling all three requirements and apply it to a recent experiment on the photoexcited phenylalanine amino acid. Our results show that dynamical correlations are necessary for a quantitative overall agreement with the experimental data. In particular, we are able to capture the transient oscillations at frequencies 0.15 and 0.30 PHz in the hole density of the amine group as well as their suppression and the concomitant development of a new oscillation at frequency 0.25 PHz after ∼14 fs.
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Affiliation(s)
- E Perfetto
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) , Area della Ricerca di Roma 1, Via Salaria Km 29.3 , I-00016 Monterotondo Scalo , Italy
- Dipartimento di Fisica , Università di Roma Tor Vergata , Via della Ricerca Scientifica 1 , 00133 Rome , Italy
| | - D Sangalli
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) , Area della Ricerca di Roma 1, Via Salaria Km 29.3 , I-00016 Monterotondo Scalo , Italy
| | - A Marini
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) , Area della Ricerca di Roma 1, Via Salaria Km 29.3 , I-00016 Monterotondo Scalo , Italy
| | - G Stefanucci
- Dipartimento di Fisica , Università di Roma Tor Vergata , Via della Ricerca Scientifica 1 , 00133 Rome , Italy
- INFN, Sezione di Roma Tor Vergata , Via della Ricerca Scientifica 1 , 00133 Rome , Italy
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36
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Gluchowski A, Gray KLG, Hood SN, Kassal I. Increases in the Charge Separation Barrier in Organic Solar Cells Due to Delocalization. J Phys Chem Lett 2018; 9:1359-1364. [PMID: 29494769 DOI: 10.1021/acs.jpclett.8b00292] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Because of the low dielectric constant, charges in organic solar cells must overcome a strong Coulomb attraction in order to separate. It has been widely argued that intermolecular delocalization would assist charge separation by increasing the effective initial electron-hole separation in a charge-transfer state, thus decreasing their barrier to separation. Here we show that this is not the case: including more than a small amount of delocalization in models of organic solar cells leads to an increase in the free-energy barrier to charge separation. Therefore, if delocalization were to improve the charge separation efficiency, it would have to do so through nonequilibrium kinetic effects that are not captured by a thermodynamic treatment of the barrier height.
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Affiliation(s)
- Adam Gluchowski
- School of Mathematics and Physics and Centre for Engineered Quantum Systems , The University of Queensland , St. Lucia , QLD 4072 , Australia
| | - Katherine L G Gray
- School of Mathematics and Physics and Centre for Engineered Quantum Systems , The University of Queensland , St. Lucia , QLD 4072 , Australia
| | - Samantha N Hood
- School of Mathematics and Physics and Centre for Engineered Quantum Systems , The University of Queensland , St. Lucia , QLD 4072 , Australia
| | - Ivan Kassal
- School of Chemistry and the University of Sydney Nano Institute , The University of Sydney , Sydney , NSW 2006 , Australia
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37
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Deng W, Gao K, Yan J, Liang Q, Xie Y, He Z, Wu H, Peng X, Cao Y. Origin of Reduced Open-Circuit Voltage in Highly Efficient Small-Molecule-Based Solar Cells upon Solvent Vapor Annealing. ACS APPLIED MATERIALS & INTERFACES 2018; 10:8141-8147. [PMID: 29411601 DOI: 10.1021/acsami.7b17546] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this study, we demonstrate that remarkably reduced open-circuit voltage in highly efficient organic solar cells (OSCs) from a blend of phenyl-C61-butyric acid methyl ester and a recently developed conjugated small molecule (DPPEZnP-THD) upon solvent vapor annealing (SVA) is due to two independent sources: increased radiative recombination and increased nonradiative recombination. Through the measurements of electroluminescence due to the emission of the charge-transfer state and photovoltaic external quantum efficiency measurement, we can quantify that the open-circuit voltage losses in a device with SVA due to the radiative recombination and nonradiative recombination are 0.23 and 0.31 V, respectively, which are 0.04 and 0.07 V higher than those of the as-cast device. Despite of the reduced open-circuit voltage, the device with SVA exhibited enhanced dissociation of charge-transfer excitons, leading to an improved short-circuit current density and a remarkable power conversion efficiency (PCE) of 9.41%, one of the best for solution-processed OSCs based on small-molecule donor materials. Our study also clearly shows that removing the nonradiative recombination pathways and/or suppressing energetic disorder in the active layer would result in more long-lived charge carriers and enhanced open-circuit voltage, which are prerequisites for further improving the PCE.
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Affiliation(s)
- Wanyuan Deng
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Ke Gao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Jun Yan
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Quanbin Liang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Yuan Xie
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Zhicai He
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Hongbin Wu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Xiaobin Peng
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Yong Cao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
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38
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Theoretical investigation on the effect of fluorine and carboxylate substitutions on the performance of benzodithiophene-diketopyrrolopyrrole-based polymer solar cells. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2228-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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39
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Yan Y, Song L, Shi Q. Understanding the free energy barrier and multiple timescale dynamics of charge separation in organic photovoltaic cells. J Chem Phys 2018; 148:084109. [DOI: 10.1063/1.5017866] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Yaming Yan
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190, China and University of Chinese Academy of Sciences, Beijing 100049, China
| | - Linze Song
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190, China and University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiang Shi
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190, China and University of Chinese Academy of Sciences, Beijing 100049, China
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Boström EV, Mikkelsen A, Verdozzi C, Perfetto E, Stefanucci G. Charge Separation in Donor-C 60 Complexes with Real-Time Green Functions: The Importance of Nonlocal Correlations. NANO LETTERS 2018; 18:785-792. [PMID: 29266952 DOI: 10.1021/acs.nanolett.7b03995] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We use the nonequilibrium Green function (NEGF) method to perform real-time simulations of the ultrafast electron dynamics of photoexcited donor-C60 complexes modeled by a Pariser-Parr-Pople Hamiltonian. The NEGF results are compared to mean-field Hartree-Fock (HF) calculations to disentangle the role of correlations. Initial benchmarking against numerically highly accurate time-dependent density matrix renormalization group calculations verifies the accuracy of NEGF. We then find that charge-transfer (CT) excitons partially decay into charge separated (CS) states if dynamical nonlocal correlation corrections are included. This CS process occurs in ∼10 fs after photoexcitation. In contrast, the probability of exciton recombination is almost 100% in HF simulations. These results are largely unaffected by nuclear vibrations; the latter become however essential whenever level misalignment hinders the CT process. The robust nature of our findings indicates that ultrafast CS driven by correlation-induced decoherence may occur in many organic nanoscale systems, but it will only be correctly predicted by theoretical treatments that include time-nonlocal correlations.
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Affiliation(s)
- Emil Viñas Boström
- Lund University , Department of Physics and European Theoretical Spectroscopy Facility (ETSF), P.O. Box 118, 221 00 Lund, Sweden
| | - Anders Mikkelsen
- Lund University , Department of Physics and NanoLund, P.O. Box 118, 221 00 Lund, Sweden
| | - Claudio Verdozzi
- Lund University , Department of Physics and European Theoretical Spectroscopy Facility (ETSF), P.O. Box 118, 221 00 Lund, Sweden
| | - Enrico Perfetto
- CNR-ISM , Division of Ultrafast Processes in Materials (FLASHit), Area della Ricerca di Roma 1, Via Salaria Km 29.3, I-00016 Monterotondo Scalo, Italy
- Dipartimento di Fisica and European Theoretical Spectroscopy Facility (ETSF), Università di Roma Tor Vergata , Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Gianluca Stefanucci
- Dipartimento di Fisica and European Theoretical Spectroscopy Facility (ETSF), Università di Roma Tor Vergata , Via della Ricerca Scientifica 1, 00133 Rome, Italy
- INFN, Sezione di Roma Tor Vergata , Via della Ricerca Scientifica 1, 00133 Rome, Italy
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41
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Few S, Chia C, Teo D, Kirkpatrick J, Nelson J. The impact of chemical structure and molecular packing on the electronic polarisation of fullerene arrays. Phys Chem Chem Phys 2018; 19:18709-18720. [PMID: 28696470 DOI: 10.1039/c7cp00317j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electronic polarisation contributes to the electronic landscape as seen by separating charges in organic materials. The nature of electronic polarisation depends on the polarisability, density, and arrangement of polarisable molecules. In this paper, we introduce a microscopic, coarse-grained model in which we treat each molecule as a polarisable site, and use an array of such polarisable dipoles to calculate the electric field and associated energy of any arrangement of charges in the medium. The model incorporates chemical structure via the molecular polarisability and molecular packing patterns via the structure of the array. We use this model to calculate energies of charge pairs undergoing separation in finite fullerene lattices of different chemical and crystal structures. The effective dielectric constants that we estimate from this approach are in good quantitative agreement with those measured experimentally in C60 and phenyl-C61-butyric acid methyl ester (PCBM) films, but we find significant differences in dielectric constant depending on packing and on direction of separation, which we rationalise in terms of density of polarisable fullerene cages in regions of high field. In general, we find lattices containing molecules of more isotropic polarisability tensors exhibit higher dielectric constants. By exploring several model systems we conclude that differences in molecular polarisability (and therefore, chemical structure) appear to be less important than differences in molecular packing and separation direction in determining the energetic landscape for charge separation. We note that the results are relevant for finite lattices, but not necessarily for infinite systems. We propose that the model could be used to design molecular systems for effective electronic screening.
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Affiliation(s)
- Sheridan Few
- Centre for Plastic Electronics, Department of Physics, Imperial College London, London SW7 2AZ, UK.
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42
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Lukina EA, Popov AA, Uvarov MN, Suturina EA, Reijerse EJ, Kulik LV. Light-induced charge separation in a P3HT/PC 70BM composite as studied by out-of-phase electron spin echo spectroscopy. Phys Chem Chem Phys 2018; 18:28585-28593. [PMID: 27711566 DOI: 10.1039/c6cp05389k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A composite material of semiconducting polymer P3HT and fullerene derivative PC70BM was studied by means of electron spin echo (ESE) spectroscopy. The out-of-phase ESE signal was observed under laser irradiation of the composite at low temperature. We assume that during the charge separation process firstly the spin-correlated radical pairs in the singlet-polarized spin state are formed, and then the net polarization of radical pairs arises due to spin evolution. Both types of polarizations contribute to the out-of-phase ESE signal in the case of non-ideal microwave pulses. Analytical calculation of the echo shape for both types of initial polarization revealed that the contribution of the net polarization becomes zero after averaging over the whole EPR spectrum of the radical pair. This behavior was experimentally confirmed; thus the analysis of the out-of-phase ESE signal was simplified. Interspin distance distributions in the charge transfer state were obtained by modeling the out-of-phase ESE envelope modulation measured at different delays after laser flash TDAF from 300 ns to 3.3 μs at a temperature of 65 K. Due to geminate recombination and diffusion of the radicals from the interface the distribution becomes significantly broader with larger distances prevailing at longer TDAF values. The average distance between charges increases from 3.5 nm to 5.6 nm with an increase in TDAF.
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Affiliation(s)
- Ekaterina A Lukina
- Voevodsky Institute of Chemical Kinetics and Combustion of Siberian Branch of Russian Academy of Sciences, Institutskaya 3, 630090 Novosibirsk, Russia. and Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
| | - Alexander A Popov
- Voevodsky Institute of Chemical Kinetics and Combustion of Siberian Branch of Russian Academy of Sciences, Institutskaya 3, 630090 Novosibirsk, Russia. and Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
| | - Mikhail N Uvarov
- Voevodsky Institute of Chemical Kinetics and Combustion of Siberian Branch of Russian Academy of Sciences, Institutskaya 3, 630090 Novosibirsk, Russia.
| | - Elizaveta A Suturina
- Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia and Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mulheim an der Ruhr, Germany
| | - Edward J Reijerse
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mulheim an der Ruhr, Germany
| | - Leonid V Kulik
- Voevodsky Institute of Chemical Kinetics and Combustion of Siberian Branch of Russian Academy of Sciences, Institutskaya 3, 630090 Novosibirsk, Russia. and Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
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43
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Nan G, Zhang X, Lu G. The lowest-energy charge-transfer state and its role in charge separation in organic photovoltaics. Phys Chem Chem Phys 2018; 18:17546-56. [PMID: 27306609 DOI: 10.1039/c6cp01622g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Energy independent, yet higher than 90% internal quantum efficiency (IQE), has been observed in many organic photovoltaics (OPVs). However, its physical origin remains largely unknown and controversial. The hypothesis that the lowest charge-transfer (CT) state may be weakly bound at the interface has been proposed to rationalize the experimental observations. In this paper, we study the nature of the lowest-energy CT (CT1) state, and show conclusively that the CT1 state is localized in typical OPVs. The electronic couplings in the donor and acceptor are found to determine the localization of the CT1 state. We examine the geminate recombination of the CT1 state and estimate its lifetime from first principles. We identify the vibrational modes that contribute to the geminate recombination. Using material parameters determined from first principles and experiments, we carry out kinetic Monte Carlo simulations to examine the charge separation of the localized CT1 state. We find that the localized CT1 state can indeed yield efficient charge separation with IQE higher than 90%. Dynamic disorder and configuration entropy can provide the energetic and entropy driving force for charge separation. Charge separation efficiency depends more sensitively on the dimension and crystallinity of the acceptor parallel to the interface than that normal to the interface. Reorganization energy is found to be the most important material parameter for charge separation, and lowering the reorganization energy of the donor should be pursued in the materials design.
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Affiliation(s)
- Guangjun Nan
- Department of Physics and Astronomy, California State University Northridge, 18111 Nordhoff Street, Northridge, California 91330-8268, USA.
| | - Xu Zhang
- Department of Physics and Astronomy, California State University Northridge, 18111 Nordhoff Street, Northridge, California 91330-8268, USA.
| | - Gang Lu
- Department of Physics and Astronomy, California State University Northridge, 18111 Nordhoff Street, Northridge, California 91330-8268, USA.
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44
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Liu D, Wang Q, Traverse CJ, Yang C, Young M, Kuttipillai PS, Lunt SY, Hamann TW, Lunt RR. Impact of Ultrathin C 60 on Perovskite Photovoltaic Devices. ACS NANO 2018; 12:876-883. [PMID: 29286630 DOI: 10.1021/acsnano.7b08561] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Halide perovskite solar cells have seen dramatic progress in performance over the past several years. Certified efficiencies of inverted structure (p-i-n) devices have now exceeded 20%. In these p-i-n devices, fullerene compounds are the most popular electron-transfer materials. However, the full function of fullerenes in perovskite solar cells is still under investigation, and the mechanism of photocurrent hysteresis suppression by fullerene remains unclear. In previous reports, thick fullerene layers (>20 nm) were necessary to fully cover the perovskite film surface to make good contact with perovskite film and avoid large leakage currents. In addition, the solution-processed fullerene layer has been broadly thought to infiltrate into the perovskite film to passivate traps on grain boundary surfaces, causing suppressed photocurrent hysteresis. In this work, we demonstrate an efficient perovskite photovoltaic device with only 1 nm C60 deposited by vapor deposition as the electron-selective material. Utilizing a combination of fluorescence microscopy and impedance spectroscopy, we show that the ultrathin C60 predominately acts to extract electrons from the perovskite film while concomitantly suppressing the photocurrent hysteresis by reducing space charge accumulation at the interface. This work ultimately helps to clarify the dominant role of fullerenes in perovskite solar cells while simplifying perovskite solar cell design to reduce manufacturing costs.
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Affiliation(s)
- Dianyi Liu
- Department of Chemical Engineering and Materials Science, ‡Department of Chemistry, §Department of Biochemistry and Molecular Biology, and ∥Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Qiong Wang
- Department of Chemical Engineering and Materials Science, ‡Department of Chemistry, §Department of Biochemistry and Molecular Biology, and ∥Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Christopher J Traverse
- Department of Chemical Engineering and Materials Science, ‡Department of Chemistry, §Department of Biochemistry and Molecular Biology, and ∥Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Chenchen Yang
- Department of Chemical Engineering and Materials Science, ‡Department of Chemistry, §Department of Biochemistry and Molecular Biology, and ∥Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Margaret Young
- Department of Chemical Engineering and Materials Science, ‡Department of Chemistry, §Department of Biochemistry and Molecular Biology, and ∥Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Padmanaban S Kuttipillai
- Department of Chemical Engineering and Materials Science, ‡Department of Chemistry, §Department of Biochemistry and Molecular Biology, and ∥Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Sophia Y Lunt
- Department of Chemical Engineering and Materials Science, ‡Department of Chemistry, §Department of Biochemistry and Molecular Biology, and ∥Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Thomas W Hamann
- Department of Chemical Engineering and Materials Science, ‡Department of Chemistry, §Department of Biochemistry and Molecular Biology, and ∥Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Richard R Lunt
- Department of Chemical Engineering and Materials Science, ‡Department of Chemistry, §Department of Biochemistry and Molecular Biology, and ∥Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
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45
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Izawa S, Nakano K, Suzuki K, Chen Y, Kikitsu T, Hashizume D, Koganezawa T, Nguyen TQ, Tajima K. Crystallization and Polymorphism of Organic Semiconductor in Thin Film Induced by Surface Segregated Monolayers. Sci Rep 2018; 8:481. [PMID: 29323176 PMCID: PMC5764981 DOI: 10.1038/s41598-017-18881-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/18/2017] [Indexed: 11/21/2022] Open
Abstract
Preparation of highly crystalline organic semiconductor films is vital to achieving high performance in electronic devices. Here we report that surface segregated monolayers (SSMs) on top of phenyl-C61-butyric acid methyl ester (PCBM) thin films induce crystal growth in the bulk, resulting in a dramatic change in the structure to form a new crystal phase. Highly ordered crystalline films with large domain sizes of several hundreds of nanometers are formed with uniaxial orientation of the crystal structure perpendicular to the substrate. The molecular rearrangements in SSMs trigger the nucleation at a lower temperature than that for the spontaneous nucleation in PCBM. The vertical charge mobility in the SSM-induced crystal domains of PCBM is five times higher than in the ordinary polycrystalline domains. Using surface monolayers may be a new strategy for controlling crystal structures and obtaining high-quality organic thin films by post-deposition crystallization.
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Affiliation(s)
- Seiichiro Izawa
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Center for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA
- Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
| | - Kyohei Nakano
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Kaori Suzuki
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Yujiao Chen
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Tomoka Kikitsu
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Daisuke Hashizume
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Tomoyuki Koganezawa
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo, Hyogo, 679-5198, Japan
| | - Thuc-Quyen Nguyen
- Center for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA
| | - Keisuke Tajima
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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46
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Tamai Y, Fan Y, Kim VO, Ziabrev K, Rao A, Barlow S, Marder SR, Friend RH, Menke SM. Ultrafast Long-Range Charge Separation in Nonfullerene Organic Solar Cells. ACS NANO 2017; 11:12473-12481. [PMID: 29148715 DOI: 10.1021/acsnano.7b06575] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Rapid, long-range charge separation in polymer-fullerene organic solar cells (OSCs) enables electrons and holes to move beyond their Coulomb capture radius and overcome geminate recombination. Understanding the nature of charge generation and recombination mechanisms in efficient, nonfullerene-acceptor-based OSCs are critical to further improve device performance. Here we report charge dynamics in an OSC using a perylene diimide (PDI) dimer acceptor. We use transient absorption spectroscopy to track the time evolution of electroabsorption caused by the dipolar electric field generated between electron-hole pairs as they separate after ionization at the donor-acceptor interface. We show that charges separate rapidly (<1 ps) and that free charge carriers are generated very efficiently (∼90% quantum yield). However, in the PDI-based OSC, external charge extraction is impaired by faster nongeminate decay to the ground state and to lower-lying triplet states.
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Affiliation(s)
- Yasunari Tamai
- Cavendish Laboratory, Department of Physics, University of Cambridge , Cambridge CB3 0HE, United Kingdom
| | - Yeli Fan
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - Vincent O Kim
- Cavendish Laboratory, Department of Physics, University of Cambridge , Cambridge CB3 0HE, United Kingdom
| | - Kostiantyn Ziabrev
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - Akshay Rao
- Cavendish Laboratory, Department of Physics, University of Cambridge , Cambridge CB3 0HE, United Kingdom
| | - Stephen Barlow
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - Seth R Marder
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - Richard H Friend
- Cavendish Laboratory, Department of Physics, University of Cambridge , Cambridge CB3 0HE, United Kingdom
| | - S Matthew Menke
- Cavendish Laboratory, Department of Physics, University of Cambridge , Cambridge CB3 0HE, United Kingdom
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47
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Scharber MC, Sarciftci NS. Bulk Heterojunction Organic Solar Cells: Working Principles and Power Conversion Efficiencies. NANOSTRUCTURED MATERIALS FOR TYPE III PHOTOVOLTAICS 2017. [DOI: 10.1039/9781782626749-00033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Bulk heterojunction solar cells are a promising low-cost photovoltaic technology. This chapter discusses the efficiency potential, the role of nanomorphology and approaches to increase the power conversion efficiency of bulk heterojunction solar cells. The stacking of devices on top of each other – constructing the so-called tandem cell – appears to be one of the best ways to reach the power conversion efficiencies necessary for the large-scale commercialization of this technology.
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Affiliation(s)
- M. C. Scharber
- Linz Institute of Organic Solar Cells, Physical Chemistry, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - N. S. Sarciftci
- Linz Institute of Organic Solar Cells, Physical Chemistry, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
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48
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D-A structural protean small molecule donor materials for solution-processed organic solar cells. CHINESE CHEM LETT 2017. [DOI: 10.1016/j.cclet.2017.08.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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49
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Jiang H, Wang Z, Zhang L, Zhong A, Liu X, Pan F, Cai W, Inganäs O, Liu Y, Chen J, Cao Y. A Highly Crystalline Wide-Band-Gap Conjugated Polymer toward High-Performance As-Cast Nonfullerene Polymer Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2017; 9:36061-36069. [PMID: 28945335 DOI: 10.1021/acsami.7b10059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A new wide-band-gap conjugated polymer PBODT was successfully synthesized that showed high crystallinity and was utilized as the active material in nonfullerene bulk-heterojunction polymer solar cells (PSCs). The photovoltaic devices based on the as-cast blend films of PBODT with ITIC and IDIC acceptors showed notable power conversion efficiencies (PCEs) of 7.06% and 9.09%, with high open-circuit voltages of 1.00 and 0.93 V that correspond to low energy losses of 0.59 and 0.69 eV, respectively. In the case of PBODT:ITIC, lower exciton quenching efficiency and monomolecular recombination are found for devices with small driving force. On the other hand, the relatively higher driving force and suppressed monomolecular recombination for PBODT:IDIC devices are identified to be the reason for their higher short-circuit current density (Jsc) and higher PCEs. In addition, when processed with the nonchlorinated solvent 1,2,4-trimethylbenzene, a good PCE of 8.19% was still achieved for the IDIC-based device. Our work shows that such wide-band-gap polymers have great potential for the environmentally friendly fabrication of highly efficient PSCs.
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Affiliation(s)
- Haiying Jiang
- Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, P. R. China
| | - Zhen Wang
- Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, P. R. China
| | - Lianjie Zhang
- Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, P. R. China
| | - Anxing Zhong
- Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, P. R. China
| | - Xuncheng Liu
- Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, P. R. China
| | - Feilong Pan
- Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, P. R. China
| | - Wanzhu Cai
- Biomolecular and Organic Electronics, Department of Physics, Chemistry and Biology, Linköping University , Linköping 58183, Sweden
| | - Olle Inganäs
- Biomolecular and Organic Electronics, Department of Physics, Chemistry and Biology, Linköping University , Linköping 58183, Sweden
| | - Yi Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory , One Cyclotron Road, Berkeley, California 94720, United States
| | - Junwu Chen
- Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, P. R. China
| | - Yong Cao
- Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, P. R. China
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50
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Guilbert AAY, Zbiri M, Dunbar ADF, Nelson J. Quantitative Analysis of the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction. J Phys Chem B 2017; 121:9073-9080. [PMID: 28834430 DOI: 10.1021/acs.jpcb.7b08312] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The optoelectronic properties of blends of conjugated polymers and small molecules are likely to be affected by the molecular dynamics of the active layer components. We study the dynamics of regioregular poly(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blends using molecular dynamics (MD) simulation on time scales up to 50 ns and in a temperature range of 250-360 K. First, we compare the MD results with quasi-elastic neutron-scattering (QENS) measurements. Experiment and simulation give evidence of the vitrification of P3HT upon blending and the plasticization of PCBM by P3HT. Second, we reconstruct the QENS signal based on the independent simulations of the three phases constituting the complex microstructure of such blends. Finally, we found that P3HT chains tend to wrap around PCBM molecules in the amorphous mixture of P3HT and PCBM; this molecular interaction between P3HT and PCBM is likely to be responsible for the observed frustration of P3HT, the plasticization of PCBM, and the partial miscibility of P3HT and PCBM.
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Affiliation(s)
- Anne A Y Guilbert
- Centre for Plastic Electronics and Department of Physics, Blackett Laboratory, Imperial College London , London SW7 2AZ, United Kingdom
| | - Mohamed Zbiri
- Institut Laue-Langevin , 71 avenue des Martyrs, Grenoble Cedex 9, 38042 France
| | - Alan D F Dunbar
- Department of Chemical and Biological Engineering, The University of Sheffield , Sheffield S1 3JD, United Kingdom
| | - Jenny Nelson
- Centre for Plastic Electronics and Department of Physics, Blackett Laboratory, Imperial College London , London SW7 2AZ, United Kingdom
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