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Dindault C, Jun H, Tondelier D, Geffroy B, Bourée JE, Bonnassieux Y, Schulz P, Swaraj S. Metal halide perovskite layers studied by scanning transmission X-ray microscopy. RSC Adv 2022; 12:25570-25577. [PMID: 36199324 PMCID: PMC9453187 DOI: 10.1039/d2ra04438b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/08/2022] [Indexed: 11/21/2022] Open
Abstract
We introduced the utility of high resolution soft X-ray STXM (scanning transmission X-ray microscopy) to study biased and unbiased wet processed metal halide perovskite layers of CH3NH3PbI3 (MAPbI3).
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Affiliation(s)
- Chloé Dindault
- Institut Photovoltaique d’Ile de France (SAS), 91120 Palaiseau, France
- LPICM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Palaiseau, France
| | - Haeyeon Jun
- LPICM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Palaiseau, France
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
| | - Denis Tondelier
- LPICM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Palaiseau, France
| | - Bernard Geffroy
- LPICM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Palaiseau, France
- CEA, CNRS, NIMBE, LICSEN, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Jean-Eric Bourée
- LPICM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Palaiseau, France
| | - Yvan Bonnassieux
- LPICM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Palaiseau, France
| | - Philip Schulz
- CNRS, Institut Photovoltaïque d’Ile de France (IPVF), UMR 9006, 18, Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - Sufal Swaraj
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
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Thickness Optimization and Photovoltaic Properties of Bulk Heterojunction Solar Cells Based on PFB–PCBM Layer. ENERGIES 2020. [DOI: 10.3390/en13225915] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We report on the fabrication and study of bulk heterojunction (BHJ) solar cells based on a novel combination of a donor–acceptor poly(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N0-diphenyl)-N,N′di(p-butyl-oxy-pheyl)-1,4-diamino-benzene) (PFB) and [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM) blend composed of 1:1 by volume. indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate (PEDOT:PSS)/PFB–PCBM/Ag BHJ solar cells are fabricated by a facile cost-effective spin-coating technique. The thickness of the active film (PFB–PCBM) plays an important role in the efficiency of light absorption, exciton creation, and dissociation into free charges that results in higher power conversion efficiency (PCE). In order to optimize the PCE as a function of active layer thickness, a number of solar cells are fabricated with different thicknesses of PFB–PCBM films at 120, 140, 160, 180, and 200 nm, and their photovoltaic characteristics are investigated. It is observed that the device with a 180 nm thick film demonstrates a maximum PCE of 2.9% with a fill factor (FF) of 53% under standard testing conditions (STC) (25 °C, 1.5 AM global, and 100 mW/cm2). The current–voltage (I-V) properties of the ITO/PEDOT:PSS/PFB–PCBM/Ag BHJ devices are also measured in dark conditions to measure and understand different parameters of the heterojunction. Atomic force microscopy (AFM) and ultraviolet-visible (UV-vis) absorption spectroscopy for the PFB–PCBM film of optimal thickness (180 nm) are carried out to understand the effect of surface morphology on the PCE and bandgap of the blend, respectively. The AFM micrographs show a slightly non-uniform and rough surface with an average surface roughness (Ra) of 29.2 nm. The UV-vis measurements of the PFB–PCBM blend exhibit a reduced optical bandgap of ≈2.34 eV as compared to that of pristine PFB (2.88 eV), which results in an improved absorption of light and excitons generation. The obtained results for the ITO/PEDOT:PSS/PFB–PCBM (180 nm)/Ag BHJ device are compared with the ones previously reported for the P3HT–PCBM blend with the same film thickness. It is observed that the PFB–PCBM-based BHJ device has shown two times higher open circuit voltage (Voc) and, hence, enhanced the efficiency.
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Fabrication and Microelectronic Properties of Hybrid Organic–Inorganic (poly(9,9, dioctylfluorene)/p-Si) Heterojunction for Electronic Applications. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10227974] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We report on the microelectronic characteristics of a novel hybrid heterojunction device based on a solution processable semiconducting polymer poly(9,9-dioctylfluorenyl-2,7-diyl)- co-(N,N0-diphenyl)-N,N′di(p-butyl-oxy-pheyl)-1,4-diamino-benzene) (PFB) and p-type silicon (p-Si). The PFB/p-Si heterojunction is prepared by spin coating 20 mg/mL solution of PFB in chloroform on the precleaned polished surface of p-Si substrate. Thermal evaporation of silver (Ag) electrode on top of PFB completes the fabrication of the Ag (90 nm)/PFB (180 nm)/p-Si heterojunction device. Morphology of PFB thin film is studied by using an atomic force microscope (AFM) and scanning electron microscope (SEM), which reveals grains are randomly distributed with slightly different grain sizes and shapes. It leads the film to form nonuniformity and some roughness in its topography that results in limiting the current (I) flow across the film/interface with p-Si. Ultraviolet (UV–vis) absorption and X-ray diffraction (XRD) spectra are measured for optical bandgap and crystal structure analysis of PFB. The key microelectronic parameters—rectification ratio (RR), ideality factor (n), barrier height (Φb), series resistance (Rs) and reverse saturation current (I0)—of the Ag/PFB/p-Si heterojunction are found from current–voltage (I–V) characteristics at room temperature (300 K) in dark conditions (≈0 lux). The Ag/PFB/p-Si heterojunction device exhibits improved microelectronic parameters when compared to those of earlier reported devices that were prepared in the same configuration. This improvement in the device parameters reveals enhancement in the microelectronic properties across the interface/depletion region of the Ag/PFB/p-Si device, which can be attributed to the remarkable electronic properties of PFB such as its relatively high hole mobility and better charge carriers’ conduction. The charge transport mechanisms through the device is also studied. Having the smaller values of I0 ≈ 7 × 10−10 A and n ≈ 3.23, as well as higher shunt resistance (Rsh) of 32 GΩ for the Ag/PFB/p-Si device suggest its potential for many electronic and optoelectronic applications.
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Li D, Titov E, Roedel M, Kolb V, Goetz S, Mitric R, Pflaum J, Brixner T. Correlating Nanoscale Optical Coherence Length and Microscale Topography in Organic Materials by Coherent Two-Dimensional Microspectroscopy. NANO LETTERS 2020; 20:6452-6458. [PMID: 32786935 DOI: 10.1021/acs.nanolett.0c02146] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Many nanotechnology materials rely on a hierarchical structure ranging from the nanometer scale to the micrometer scale. Their interplay determines the nanoscale optical coherence length, which plays a key role in energy transport and radiative decay and, thus, the optoelectronic applications. However, it is challenging to detect optical coherence length in multiscale structures with existing methods. Techniques such as atomic force microscopy and transmission electron microscopy are not sensitive to optical coherence length. Linear absorption and fluorescence spectroscopy methods, on the other hand, were generally limited by inhomogeneous broadening, which often obstructs the determination of nanoscale coherence length. Here, we carry out coherent two-dimensional microspectroscopy to obtain a map of the local optical coherence length within a hierarchically structured molecular film. Interestingly, the nanoscale coherence length is found to correlate with microscale topography, suggesting a perspective for controlling structural coherence on molecular length scales by appropriate microscopic growth conditions.
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Affiliation(s)
- Donghai Li
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Evgenii Titov
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Maximilian Roedel
- Lehrstuhl für Experimentelle Physik VI, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Verena Kolb
- Lehrstuhl für Experimentelle Physik VI, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Sebastian Goetz
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Roland Mitric
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Jens Pflaum
- Lehrstuhl für Experimentelle Physik VI, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Bavarian Center for Applied Energy Research e.V. (ZAE Bayern), Magdalene-Schoch-Str. 3, 97074 Würzburg, Germany
| | - Tobias Brixner
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074 Würzburg, Germany
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Ostrowski DP, Vanden Bout DA. Correlation of morphology with photocurrent generation in a polymer blend photovoltaic device. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:1821-1829. [PMID: 24482361 DOI: 10.1002/smll.201303262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 11/15/2013] [Indexed: 06/03/2023]
Abstract
Morphological effects on photovoltaic (PV) properties are studied through scanning photocurrent (PC) and photoluminescence (PL) microscopy of a solution processed, polymer blend PV device composed of PFB [poly(9,9'-dioctylfluorene-co-bis-N,N-(4-butylphenyl)-bis-N,N-phenyl-1,4-phenylenediamine] and F8BT [poly(9,9'-dioctylfluorene-co-benzothiadiazole]. As PFB and F8BT have unique absorbance bands, it is possible to selectively excite only F8BT (488 nm) or both PFB and F8BT (408 nm). Local voltage-dependent photocurrent (LVPC) measurements from particular regions of interest in the PV show that the diode characteristics between different morphologies are essentially the same, except in regard to the magnitude of PC generated. A local PL spectrum is measured simultaneously with PC generation at each pixel in the image maps. Through integration of the local PL spectrum over particular wavelength ranges, PL image maps are created of PFB-PL (435 to 475 nm), F8BT-PL (530 to 570 nm), exciplex-PL (620 to 685 nm) and total-PL (entire spectrum). These data allow direct correlation of PC generation with local chemical composition variations within the PV device. PL image maps show morphological variations on the order of 0.5 to 1 µm of alternating PFB-rich and F8BT-rich phases. While illuminating only F8BT (488 nm light), the PFB-rich phases produce the most PC, however, while illuminating both polymers but mostly PFB (408 nm light), the F8BT-rich phases produce the most PC. These results show that in the morphology where the light absorbing material is less concentrated, the PC generation is increased. Additionally, the exciplex-PL is found to not be a significant radiative loss mechanism of charge carriers for PC generation.
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Affiliation(s)
- David P Ostrowski
- Department of Chemistry and Biochemistry and the Center for Nano and Molecular Science, at The University of Texas at Austin, Welch Hall 2.204, 105 E. 24th Street, A5300, Austin, TX, 78712-1224, USA
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Yan C, Cadby AJ, Parnell AJ, Tang W, Skoda MWA, Mohamad D, King SP, Reynolds LX, Haque SA, Wang T, Parnell SR, Holmes AB, Jones RAL, Jones DJ. Photophysics and morphology of a polyfluorene donor-acceptor triblock copolymer for solar cells. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/polb.23386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Chao Yan
- School of Chemistry; Bio21 Institute; Building 102; 30 Flemington Road; The University of Melbourne; Parkville Victoria 3010 Australia
| | - Ashley J. Cadby
- Department of Physics and Astronomy; The University of Sheffield; Hicks Building, Hounsfield Road Sheffield S3 7RH United Kingdom
| | - Andrew J. Parnell
- Department of Physics and Astronomy; The University of Sheffield; Hicks Building, Hounsfield Road Sheffield S3 7RH United Kingdom
| | - Weihua Tang
- School of Chemistry; Bio21 Institute; Building 102; 30 Flemington Road; The University of Melbourne; Parkville Victoria 3010 Australia
| | - Maximilian W. A. Skoda
- ISIS Pulsed Neutron and Muon Source; Science and Technology Facilities Council; Rutherford Appleton Laboratory; Harwell Science and Innovation Campus; Didcot OX11 0QX United Kingdom
| | - David Mohamad
- Department of Physics and Astronomy; The University of Sheffield; Hicks Building, Hounsfield Road Sheffield S3 7RH United Kingdom
| | - Simon P. King
- Imperial College London; Department of Chemistry; South Kensington Campus; London SW7 2AZ United Kingdom
| | - Luke X. Reynolds
- Imperial College London; Department of Chemistry; South Kensington Campus; London SW7 2AZ United Kingdom
| | - Saif A. Haque
- Imperial College London; Department of Chemistry; South Kensington Campus; London SW7 2AZ United Kingdom
| | - Tao Wang
- Department of Physics and Astronomy; The University of Sheffield; Hicks Building, Hounsfield Road Sheffield S3 7RH United Kingdom
| | - Steven R. Parnell
- Low Energy Neutron Source (LENS) Indiana University; Bloomington Indiana Indiana 47408
| | - Andrew B. Holmes
- School of Chemistry; Bio21 Institute; Building 102; 30 Flemington Road; The University of Melbourne; Parkville Victoria 3010 Australia
| | - Richard A. L. Jones
- Department of Physics and Astronomy; The University of Sheffield; Hicks Building, Hounsfield Road Sheffield S3 7RH United Kingdom
| | - David J. Jones
- School of Chemistry; Bio21 Institute; Building 102; 30 Flemington Road; The University of Melbourne; Parkville Victoria 3010 Australia
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7
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Ruderer MA, Wang C, Schaible E, Hexemer A, Xu T, Müller-Buschbaum P. Morphology and Optical Properties of P3HT:MEH-CN-PPV Blend Films. Macromolecules 2013. [DOI: 10.1021/ma4006999] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Matthias A. Ruderer
- Lehrstuhl für Funktionelle
Materialien, Physik-Department, Technische Universität München, James-Franck-Strasse 1, 85748 Garching,
Germany
| | - Cheng Wang
- Advanced Light
Source, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Eric Schaible
- Advanced Light
Source, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Alexander Hexemer
- Advanced Light
Source, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Ting Xu
- Department of Materials Science
and Engineering and Department of Chemistry, University of California Berkeley, Berkeley, California 94720,
United States
| | - Peter Müller-Buschbaum
- Lehrstuhl für Funktionelle
Materialien, Physik-Department, Technische Universität München, James-Franck-Strasse 1, 85748 Garching,
Germany
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9
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Rivnay J, Mannsfeld SCB, Miller CE, Salleo A, Toney MF. Quantitative Determination of Organic Semiconductor Microstructure from the Molecular to Device Scale. Chem Rev 2012; 112:5488-519. [DOI: 10.1021/cr3001109] [Citation(s) in RCA: 939] [Impact Index Per Article: 78.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Jonathan Rivnay
- Department of Materials Science
and Engineering, Stanford University, Stanford, California 94305,
United States
| | - Stefan C. B. Mannsfeld
- Stanford
Synchrotron Radiation
Lightsource (SSRL), SLAC National Accelerator Laboratory, Menlo Park,
California 94025, United States
| | - Chad E. Miller
- Stanford
Synchrotron Radiation
Lightsource (SSRL), SLAC National Accelerator Laboratory, Menlo Park,
California 94025, United States
| | - Alberto Salleo
- Department of Materials Science
and Engineering, Stanford University, Stanford, California 94305,
United States
| | - Michael F. Toney
- Stanford
Synchrotron Radiation
Lightsource (SSRL), SLAC National Accelerator Laboratory, Menlo Park,
California 94025, United States
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Yan H, Collins BA, Gann E, Wang C, Ade H, McNeill CR. Correlating the efficiency and nanomorphology of polymer blend solar cells utilizing resonant soft X-ray scattering. ACS NANO 2012; 6:677-688. [PMID: 22168639 DOI: 10.1021/nn204150f] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Enhanced scattering contrast afforded by resonant soft X-ray scattering (R-SoXS) is used to probe the nanomorphology of all-polymer solar cells based on blends of the donor polymer poly(3-hexylthiophene) (P3HT) with either the acceptor polymer poly((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole]-2',2"-diyl) (F8TBT) or poly([N,N'-bis(2-octyldodecyl)-11-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-12-bithiophene)) (P(NDI2OD-T2)). Both P3HT:F8TBT and P3HT:P(NDI2OD-T2) blends processed from chloroform with subsequent annealing exhibit complicated morphologies with a hierarchy of phase separation. A bimodal distribution of domain sizes is observed for P3HT:P(NDI2OD-T2) blends with small domains of size ~5-10 nm that evolve with annealing and larger domains of size ~100 nm that are insensitive to annealing. P3HT:F8TBT blends in contrast show a broader distribution of domain size but with the majority of this blend structured on the 10 nm length scale. For both P3HT:P(NDI2OD-T2) and P3HT:F8TBT blends, an evolution in device performance is observed that is correlated with a coarsening and purification of domains on the 5-10 nm length scale. Grazing-incidence wide-angle X-ray scattering (GI-WAXS) is also employed to probe material crystallinity, revealing P(NDI2OD-T2) crystallites 25-40 nm in thickness that are embedded in the larger domains observed by R-SoXS. A higher degree of P3HT crystallinity is also observed in blends with P(NDI2OD-T2) compared to F8TBT with the propensity of the polymers to crystallize in P3HT:P(NDI2OD-T2) blends hindering the structuring of morphology on the sub-10 nm length scale. This work also underscores the complementarity of R-SoXS and GI-WAXS, with R-SoXS measuring the size of compositionally distinguishable domains and GI-WAXS providing information regarding crystallinity and crystallite thickness.
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Affiliation(s)
- Hongping Yan
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202, USA
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Kozub DR, Vakhshouri K, Kesava SV, Wang C, Hexemer A, Gomez ED. Direct measurements of exciton diffusion length limitations on organic solar cell performance. Chem Commun (Camb) 2012; 48:5859-61. [DOI: 10.1039/c2cc31925j] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Frisch J, Schubert M, Preis E, Rabe JP, Neher D, Scherf U, Koch N. Full electronic structure across a polymer heterojunction solar cell. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c1jm14968g] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Burke KB, Stapleton AJ, Vaughan B, Zhou X, Kilcoyne ALD, Belcher WJ, Dastoor PC. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales. NANOTECHNOLOGY 2011; 22:265710. [PMID: 21586810 DOI: 10.1088/0957-4484/22/26/265710] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.
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Affiliation(s)
- Kerry B Burke
- Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308, Australia
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Watts B, Swaraj S, Nordlund D, Lüning J, Ade H. Calibrated NEXAFS spectra of common conjugated polymers. J Chem Phys 2011; 134:024702. [PMID: 21241141 DOI: 10.1063/1.3506636] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Near edge x-ray absorption fine structure (NEXAFS) spectroscopy has evolved into a powerful characterization tool for polymeric materials and is increasingly being used to elucidate composition and orientation in thin films of relevance to organic electronic devices. For accurate quantitative compositional analysis, insight into the electronic structure and the ability to assess molecular orientation, reliable reference spectra with known energy resolution and calibrated energy scale are required. We report a set of such NEXAFS spectra from 23 semiconducting polymers and some related materials that are frequently used in organic device research.
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Affiliation(s)
- B Watts
- North Carolina State University, Raleigh, North Carolina 27695, USA.
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15
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Salim T, Wong LH, Bräuer B, Kukreja R, Foo YL, Bao Z, Lam YM. Solvent additives and their effects on blend morphologies of bulk heterojunctions. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm01976c] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Swaraj S, Wang C, Yan H, Watts B, Lüning J, McNeill CR, Ade H. Nanomorphology of bulk heterojunction photovoltaic thin films probed with resonant soft X-ray scattering. NANO LETTERS 2010; 10:2863-2869. [PMID: 20590125 DOI: 10.1021/nl1009266] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The bulk nanomorphology of organic bulk heterojunction devices, particularly of all-polymer devices, is difficult to characterize due to limited electron density contrast between constituent materials. Resonant soft X-ray scattering can overcome this problem and is used to show that the morphologies in chloroform cast and subsequently annealed polyfluorene copolymer poly(9,9'-dioctylfluorene-co-bis(N,N'-(4,butylphenyl))bis(N,N'-phenyl-1,4-phenylene)diamine) (PFB) and poly(9,9'-dioctylfluorene-co-benzothiadiazole) (F8BT) blends exhibit a hierarchy of length scales with impure domains in as-cast films. With annealing, these domains first become purer at the smallest length scale and only then evolve in size with annealing. Even optimized cells using present fabrication methods are found to have a dominant domain size much larger than the exciton diffusion length. The observed morphology is far from ideal for efficient solar cell operation and very different from those achieved in high-efficiency fullerene-based devices. This strongly implies that lack of morphological control contributes to the relatively poor performance of the all-polymer PFB/F8BT devices and may be problematic for all-polymer devices in general. Novel processing strategies will have to be employed to harness the full potential these high open circuit voltage devices offer.
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Affiliation(s)
- Sufal Swaraj
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
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Zhao K, Zhou G, Wang Q, Han Y, Wang L, Ma D. Phase Separation in Poly(9,9-dioctylfluorene)/Poly(methyl methacrylate) Blends. MACROMOL CHEM PHYS 2009. [DOI: 10.1002/macp.200900412] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ade H, Stoll H. Near-edge X-ray absorption fine-structure microscopy of organic and magnetic materials. NATURE MATERIALS 2009; 8:281-90. [PMID: 19308087 DOI: 10.1038/nmat2399] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Many high-performance materials and novel devices consist of multiple components and are naturally or intentionally nano-structured for optimal properties and performance. To understand their structure-property relationships fully, quantitative compositional analysis at length scales below 100 nm is required, a need that is often uniquely addressed using soft X-ray microscopy. Similarly, the interaction of X-rays with magnetic materials provides unique element-specific contrast that allows the determination of magnetic properties in multi-element antiferromagnetic and ferromagnetic materials. Pump-probe-type experiments can even investigate magnetic domain dynamics. Here we review and exemplify the ability of soft X-ray microscopy to provide information that is otherwise inaccessible, and discuss a perspective on future developments.
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Affiliation(s)
- Harald Ade
- Department of Physics, NCSU, Raleigh, North Carolina 27695, USA.
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