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Singh AK, Kavungathodi MFM, Mozer AJ, Krishnamoorthy K, Nithyanandhan J. Solvent-Dependent Functional Aggregates of Unsymmetrical Squaraine Dyes on TiO 2 Surface for Dye-Sensitized Solar Cells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:14808-14818. [PMID: 36417560 DOI: 10.1021/acs.langmuir.2c02469] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Alkyl group wrapped donor-acceptor-donor (D-A-D) based unsymmetrical squaraine dyes SQ1, SQ5, and SQS4 were used to evaluate the effect of sensitizing solvents on dye-sensitized solar cell (DSSC) efficiency. A drastic change in DSSC efficiency was observed when the photo-anodes were sensitized in acetonitrile (bad solvent when considering dye solubility) and chloroform (good solvent) with an Iodolyte (I-/I3-) electrolyte. The DSSC device sensitized with squaraine dyes in acetonitrile showed better photovoltaic performance with enhanced photocurrent generation and photovoltage compared to the device sensitized in chloroform. In a good sensitizing solvent, dyes with long hydrophobic alkyl chains are deleterious forming aggregates on the TiO2 surface, which results in an incident photon-to-current conversion efficiency (IPCE) response mostly from monomeric and dimeric structures. Meanwhile, a bad sensitizing solvent facilitates the formation of well-packed self-assembled structures on the TiO2 surface, which are responsible for a broad IPCE response and high device efficiencies. The photoanode sensitized in the bad sensitizing solvent showed enhanced VOC values of 642, 675, and 699 mV; JSC values of 6.38, 11.1, and 11.69 mA/cm2; and DSSC device efficiencies of 3.0, 5.63, and 6.13% for the SQ1, SQ5, and SQS4 dyes in the absence of a coadsorbent (chenodeoxycholic acid (CDCA)), respectively, which were further enhanced by CDCA addition. Meanwhile, the photoanode sensitized in the good sensitizing solvent showed relatively low photovoltaic VOC values of 640, 652, and 650 mV; JSC values of 5.78, 6.79, and 6.24 mA/cm2; and device efficiencies of 2.73, 3.35, and 3.20% for SQ1, SQ5, and SQS4 in the absence of CDCA, respectively, which were further varied with equivalents of CDCA. The best DSSC device efficiencies of 6.13 and 3.20% were obtained for SQS4 without CDCA, where the dye was sensitized in acetonitrile (bad) and chloroform (good) sensitizing solvents, respectively.
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Affiliation(s)
- Ambarish Kumar Singh
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory and CSIR-Network of Institutes for Solar Energy, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Munavvar Fairoos Mele Kavungathodi
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Attila J Mozer
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Kothandam Krishnamoorthy
- Polymer Science and Engineering Division, CSIR-National Chemical Laboratory and CSIR-Network of Institutes for Solar Energy, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Jayaraj Nithyanandhan
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory and CSIR-Network of Institutes for Solar Energy, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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Clementi C, Romani A, Elisei F, De Angelis F, Daus F, Nunzi F. The dependence of the spectroscopic properties of orcein dyes on solvent proticity: insights from theory and experiments. Phys Chem Chem Phys 2021; 23:15329-15337. [PMID: 34254084 DOI: 10.1039/d1cp01535d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic spectral properties of α-hydroxy-orcein (α-HO), one of the main components of the orcein dye, have been extensively investigated in solvents of different proticity through UV-Vis spectrophotometry combined with DFT and TDDFT calculations. The results highlight the occurrence of an acid-base equilibrium between the neutral (absorption maximum at 475 nm) and the monoanionic (absorption maximum at 578 nm) forms of the molecule. The position of this equilibrium was found to be sensitively dependent on solvent proticity, solution concentration and pH. Quantum mechanical calculations support the rationalization of the experimental data, confirming the key role of the protic solvent in shifting the acid-base equilibrium, through the establishment of hydrogen bond interactions on specific functional groups of the dye. Both deprotonation and dye coordination with protic solvent molecules determine the reduction of the HOMO-LUMO energy gap (0.71 eV), that can be related with the bathochromic effect envisaged both experimentally (0.59 eV) and theoretically (0.50 eV).
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Affiliation(s)
- Catia Clementi
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy.
| | - Aldo Romani
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy. and Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta" (CNR-SCITEC), via Elce di Sotto, I-06123 Perugia, Italy.
| | - Fausto Elisei
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy.
| | - Filippo De Angelis
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy. and Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta" (CNR-SCITEC), via Elce di Sotto, I-06123 Perugia, Italy.
| | - Federica Daus
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy.
| | - Francesca Nunzi
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy. and Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta" (CNR-SCITEC), via Elce di Sotto, I-06123 Perugia, Italy.
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Xu F, Testoff TT, Wang L, Zhou X. Cause, Regulation and Utilization of Dye Aggregation in Dye-Sensitized Solar Cells. Molecules 2020; 25:E4478. [PMID: 33003462 PMCID: PMC7582523 DOI: 10.3390/molecules25194478] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/23/2020] [Accepted: 09/25/2020] [Indexed: 11/16/2022] Open
Abstract
As an important member of third generation solar cell, dye-sensitized solar cells (DSSCs) have the advantages of being low cost, having an easy fabrication process, utilizing rich raw materials and a high-power conversion efficiency (PCE), prompting nearly three decades as a research hotspot. Recently, increasing the photoelectric conversion efficiency of DSSCs has proven troublesome. Sensitizers, as the most important part, are no longer limited to molecular engineering, and the regulation of dye aggregation has become a widely held concern, especially in liquid DSSCs. This review first presents the operational mechanism of liquid and solid-state dye-sensitized solar cells, including the influencing factors of various parameters on device efficiency. Secondly, the mechanism of dye aggregation was explained by molecular exciton theory, and the influence of various factors on dye aggregation was summarized. We focused on a review of several methods for regulating dye aggregation in liquid and solid-state dye-sensitized solar cells, and the advantages and disadvantages of these methods were analyzed. In addition, the important application of quantum computational chemistry in the study of dye aggregation was introduced. Finally, an outlook was proposed that utilizing the advantages of dye aggregation by combining molecular engineering with dye aggregation regulation is a research direction to improve the performance of liquid DSSCs in the future. For solid-state dye-sensitized solar cells (ssDSSCs), the effects of solid electrolytes also need to be taken into account.
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Affiliation(s)
- Fang Xu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300345, China; (F.X.); (L.W.)
| | - Thomas T. Testoff
- Department of Chemistry and Biochemistry and the Materials Technology Center, Southern Illinois University, Carbondale, IL 62901, USA;
| | - Lichang Wang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300345, China; (F.X.); (L.W.)
- Department of Chemistry and Biochemistry and the Materials Technology Center, Southern Illinois University, Carbondale, IL 62901, USA;
| | - Xueqin Zhou
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300345, China; (F.X.); (L.W.)
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Prampolini G, Ingrosso F, Segalina A, Caramori S, Foggi P, Pastore M. Dynamical and Environmental Effects on the Optical Properties of an Heteroleptic Ru(II)–Polypyridine Complex: A Multilevel Approach Combining Accurate Ground and Excited State QM-Derived Force Fields, MD and TD-DFT. J Chem Theory Comput 2018; 15:529-545. [DOI: 10.1021/acs.jctc.8b01031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Giacomo Prampolini
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Francesca Ingrosso
- Université de Lorraine, CNRS, Laboratoire de Physique et Chimie Théoriques, F-54000 Nancy, France
| | - Alekos Segalina
- Université de Lorraine, CNRS, Laboratoire de Physique et Chimie Théoriques, F-54000 Nancy, France
| | - Stefano Caramori
- Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Ferrara, Via Luigi Borsari 46, I-44100, Ferrara, Italy
| | - Paolo Foggi
- European Laboratory for Non Linear Spectroscopy (LENS), Università di Firenze, Via Nello Carrara 1, I-50019 Sesto Fiorentino Florence, Italy
- INO−CNR, Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo Fermi 6, I-50125 Florence, Italy
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Mariachiara Pastore
- Université de Lorraine, CNRS, Laboratoire de Physique et Chimie Théoriques, F-54000 Nancy, France
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Ghafoor S, Hussain SZ, Waseem S, Arshad SN. Photo-reduction of heavy metal ions and photo-disinfection of pathogenic bacteria under simulated solar light using photosensitized TiO 2 nanofibers. RSC Adv 2018; 8:20354-20362. [PMID: 35541678 PMCID: PMC9080839 DOI: 10.1039/c8ra01237g] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/29/2018] [Indexed: 11/21/2022] Open
Abstract
We report the photosensitization of electrospun titania nanofibers, with a mean diameter of 195 nm, by low bandgap silver sulfide nanoparticles of 11-23 nm mean size with the aim of treating heavy metal ions and pathogenic bacteria simultaneously under simulated solar light irradiation. The 17 nm Ag2S/TiO2 nanofibers showed 90% photocatalytic reduction of Cr(vi) at pH of 3 with a pseudo-first order rate constant of 0.016 min-1 which is significantly better than the previously reported for Ag-Ag2S/TiO2 composite particles. The antibacterial capability of the Ag2S/TiO2 nanofibers was evaluated via photo-disinfection of the Gram-positive and Gram-negative bacterial strains. The smallest sized 11 nm Ag2S/TiO2 nanofiber showed the best bactericidal efficiency of 100% and 90.6% against Gram-negative E. coli and Gram-positive S. aureus after 1 h of irradiation, respectively, whereas, only 50% E. coli and 41% S. aureus were found to be inactivated in dark. Furthermore, a UV-O3 treatment of the 11 nm Ag2S/TiO2 nanofibers remarkably enhanced the antibacterial activity where 89% E. coli and 81% S. aureus were inactivated in just 10 min of the irradiation. Enhanced photocatalytic activity is attributed to the efficient charge separation and transfer and reduced electron-hole recombination induced by the effective heterojunction formation between TiO2 and the optimally sized Ag2S nanoparticles. The disinfection nature of the Ag2S nanoparticles, role of the generated hydroxyl species under irradiation, and the cell wall damage mechanism is also discussed. This study demonstrates the potential use of these multifunctional composite TiO2 nanofibers for water remediation.
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Affiliation(s)
- Samina Ghafoor
- Department of Chemistry and Chemical Engineering, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences Lahore 54792 Pakistan
- Institute of Chemistry, University of the Punjab P. O. Box 54590 Lahore Pakistan
| | - Syed Zajif Hussain
- Department of Chemistry and Chemical Engineering, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences Lahore 54792 Pakistan
| | - Sadia Waseem
- Institute of Chemistry, University of the Punjab P. O. Box 54590 Lahore Pakistan
| | - Salman Noshear Arshad
- Department of Chemistry and Chemical Engineering, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences Lahore 54792 Pakistan
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Castellucci E, Monini M, Bessi M, Iagatti A, Bussotti L, Sinicropi A, Calamante M, Zani L, Basosi R, Reginato G, Mordini A, Foggi P, Di Donato M. Photoinduced excitation and charge transfer processes of organic dyes with siloxane anchoring groups: a combined spectroscopic and computational study. Phys Chem Chem Phys 2018; 19:15310-15323. [PMID: 28569917 DOI: 10.1039/c7cp01956d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dye-sensitized solar cells (DSSCs) have attracted significant interest in the last few years as effective low-cost devices for solar energy conversion. We have analyzed the excited state dynamics of several organic dyes bearing both cyanoacrylic acid and siloxane anchoring groups. The spectroscopic properties of the dyes have been studied both in solution and when adsorbed on a TiO2 film using stationary and time-resolved techniques, probing the sub-picosecond to nanosecond time interval. The comparison between the spectra registered in solution and on the solid substrate evidences different pathways for energy and electron relaxation. The transient spectra of the TiO2-adsorbed dyes show the appearance of a long wavelength excited state absorption band, attributed to the cationic dye species, which is absent in the spectra measured in solution. Furthermore, the kinetic traces of the samples adsorbed on the TiO2 film show a long decay component not present in solution which constitutes indirect evidence of electron transfer between the dye and the semiconductor. The interpretation of the experimental results has been supported by theoretical DFT calculations of the excited state energies and by the analysis of molecular orbitals of the analyzed dye molecules.
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Affiliation(s)
- Elena Castellucci
- LENS (European Laboratory for Non-Linear Spectroscopy), Via N. Carrara 1, 50019 Sesto Fiorentino, Italy
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7
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Zhang L, Liu X, Rao W, Li J. Multilayer Dye Aggregation at Dye/TiO 2 Interface via π…π Stacking and Hydrogen Bond and Its Impact on Solar Cell Performance: A DFT Analysis. Sci Rep 2016; 6:35893. [PMID: 27767196 PMCID: PMC5073288 DOI: 10.1038/srep35893] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/06/2016] [Indexed: 01/03/2023] Open
Abstract
Multilayer dye aggregation at the dye/TiO2 interface of dye-sensitized solar cells is probed via first principles calculations, using p-methyl red azo dye as an example. Our calculations suggest that the multilayer dye aggregates at the TiO2 surface can be stabilized by π…π stacking and hydrogen bond interactions. Compared with previous two-dimensional monolayer dye/TiO2 model, the multilayer dye aggregation model proposed in this study constructs a three-dimensional multilayer dye/TiO2 interfacial structure, and provides a better agreement between experimental and computational results in dye coverage and dye adsorption energy. In particular, a dimer forms by π…π stacking interactions between two neighboring azo molecules, while one of them chemisorbs on the TiO2 surface; a trimer may form by introducing one additional azo molecule on the dimer through a hydrogen bond between two carboxylic acid groups. Different forms of multilayer dye aggregates, either stabilized by π…π stacking or hydrogen bond, exhibit varied optical absorption spectra and electronic properties. Such variations could have a critical impact on the performance of dye sensitized solar cells.
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Affiliation(s)
- Lei Zhang
- Department of Applied Physics, School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, No. 219 Ning Liu Road, Nanjing 210044, China
| | - Xiaogang Liu
- Singapore-MIT Alliance for Research and Technology (SMART) Centre, 1 Create Way, 138602, Singapore
| | - Weifeng Rao
- Department of Materials Physics, School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Jingfa Li
- Department of Applied Physics, School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, No. 219 Ning Liu Road, Nanjing 210044, China
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Feng S, Li QS, Sun PP, Niehaus TA, Li ZS. Dynamic Characteristics of Aggregation Effects of Organic Dyes in Dye-Sensitized Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2015; 7:22504-22514. [PMID: 26391331 DOI: 10.1021/acsami.5b06743] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Two organic dyes (LS-1 and IQ4) containing identical electron donor and acceptor units but distinct π units result in significantly different power conversion efficiency of the corresponding dye-sensitized solar cells (DSSCs): LS-1, 4.4%, and IQ4, 9.2%. Herein, we combine first-principle calculations and molecular dynamics to explore the aggregation effects of LS-1 and IQ4 by comparing their optical properties and intermolecular electronic couplings. The calculated absorption spectra are in good agreement with the experimental observations and reveal them to be evidently affected by the dimerization. Furthermore, molecular dynamics simulations show that steric hindrance induced by the diphenylquinoxaline unit in IQ4 can elongate the distances between intermolecular π units or electron donors, which are responsible for the fact that the intermolecular electronic coupling of LS-1 is about 10 times larger than that of IQ4. More importantly, the aggregated IQ4 remains almost perpendicular to the TiO2 surface, whereas LS-1 gradually tilts during the dynamic simulation, impacting electron injection and recombination in several ways, which clarifies why IQ4 leads to larger photocurrent and higher conversion efficiency. The deep understanding of the dye aggregation effects sheds new light on the complex factors determining DSSC function and paves the way for rational design of high-efficiency self-anti-aggregation sensitizers.
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Affiliation(s)
- Shuai Feng
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry, Beijing Institute of Technology , Beijing 100081, China
- College of Chemistry and Chemical Engineering, Taishan University , Taian 271021, China
| | - Quan-Song Li
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry, Beijing Institute of Technology , Beijing 100081, China
| | - Ping-Ping Sun
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry, Beijing Institute of Technology , Beijing 100081, China
| | - Thomas A Niehaus
- Department of Theoretical Physics, University of Regensburg , 93040 Regensburg, Germany
| | - Ze-Sheng Li
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry, Beijing Institute of Technology , Beijing 100081, China
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Dryza V, Bieske EJ. Does the triphenylamine-based D35 dye sensitizer form aggregates on metal-oxide surfaces? J Photochem Photobiol A Chem 2015. [DOI: 10.1016/j.jphotochem.2015.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Abate A, Pérez-Tejada R, Wojciechowski K, Foster JM, Sadhanala A, Steiner U, Snaith HJ, Franco S, Orduna J. Phosphonic anchoring groups in organic dyes for solid-state solar cells. Phys Chem Chem Phys 2015; 17:18780-9. [DOI: 10.1039/c5cp02671g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Performance of new metal-free organic dyes for solid-state dye-sensitized solar cells with carboxylic and phosphonic acids as TiO2 anchoring groups.
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Affiliation(s)
- Antonio Abate
- Department of Physics
- University of Oxford
- Oxford
- UK
- Cavendish Laboratory
| | - Raquel Pérez-Tejada
- Instituto de Ciencia Materiales de Aragón
- Departamento de Química Orgánica
- Universidad de Zaragoza-CSIC
- Spain
| | | | - Jamie M. Foster
- Department of Mathematics & Statistics
- McMaster University
- Hamilton
- Canada
| | - Aditya Sadhanala
- Cavendish Laboratory
- Department of Physics
- University of Cambridge
- Cambridge
- UK
| | - Ullrich Steiner
- Cavendish Laboratory
- Department of Physics
- University of Cambridge
- Cambridge
- UK
| | | | - Santiago Franco
- Instituto de Ciencia Materiales de Aragón
- Departamento de Química Orgánica
- Universidad de Zaragoza-CSIC
- Spain
| | - Jesús Orduna
- Instituto de Ciencia Materiales de Aragón
- Departamento de Química Orgánica
- Universidad de Zaragoza-CSIC
- Spain
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Zhang F, Ma W, Jiao Y, Wang J, Shan X, Li H, Lu X, Meng S. Precise identification and manipulation of adsorption geometry of donor-π-acceptor dye on nanocrystalline TiO₂ films for improved photovoltaics. ACS APPLIED MATERIALS & INTERFACES 2014; 6:22359-69. [PMID: 25418522 DOI: 10.1021/am506365a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Adsorption geometry of dye molecules on nanocrystalline TiO2 plays a central role in dye-sensitized solar cells, enabling effective sunlight absorption, fast electron injection, optimized interface band offsets, and stable photovoltaic performance. However, precise determination of dye binding geometry and proportion has been challenging due to complexity and sensitivity at interfaces. Here employing combined vibrational spectrometry and density functional calculations, we identify typical adsorption configurations of widely adopted cyanoacrylic donor-π bridge-acceptor dyes on nanocrystalline TiO2. Binding mode switching from bidentate bridging to hydrogen-bonded monodentate configuration with Ti-N bonding has been observed when dye-sensitizing solution becomes more basic. Raman and infrared spectroscopy measurements confirm this configuration switch and determine quantitatively the proportion of competing binding geometries, with vibration peaks assigned using density functional theory calculations. We further found that the proportion of dye-binding configurations can be manipulated by adjusting pH value of dye-sensitizing solutions. Controlling molecular adsorption density and configurations led to enhanced energy conversion efficiency from 2.4% to 6.1% for the fabricated dye-sensitized solar cells, providing a simple method to improve photovoltaic performance by suppressing unfavorable binding configurations in solar cell applications.
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Affiliation(s)
- Fan Zhang
- Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences , Beijing, 100190, P. R. China
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Zhang J, Zhang JZ, Li HB, Wu Y, Geng Y, Su ZM. Rational modifications on champion porphyrin dye SM315 using different electron-withdrawing moieties toward high performance dye-sensitized solar cells. Phys Chem Chem Phys 2014; 16:24994-5003. [DOI: 10.1039/c4cp03355h] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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A comparison of carboxypyridine isomers as sensitizers for dye-sensitized solar cells: assessment of device efficiency and stability. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.05.076] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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