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Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends

Journal Article · · Energy & Environmental Science
DOI:https://doi.org/10.1039/d2ee03883h· OSTI ID:2419588
 [1];  [2];  [3];  [2];  [2];  [3];  [3];  [3];  [2];  [3];  [2];  [2];  [2];  [2];  [3];  [2];  [2];  [4];  [2]
  1. Northwestern Univ., Evanston, IL (United States); Tianjin Univ. (China); OSTI
  2. Northwestern Univ., Evanston, IL (United States)
  3. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  4. Northwestern Univ., Evanston, IL (United States); Flexterra Corporation, Skokie, IL (United States)
Addressing pertinent and perplexing questions regarding why nonfullerene acceptors (NFAs) promote higher power conversion efficiencies (PCEs) than traditional fullerenes and how photoactive bulk heterojunction (BHJ) film morphology, charge photogeneration, and recombination dynamics dictate solar cell performance have stimulated many studies of polymer solar cells (PSCs), yet quantitative relationships remain limited. Better understanding in these areas offers the potential to advance materials design and device engineering, afford higher PCEs, and ultimate commercialization. Here we probe quantitative relationships between BHJ film morphology, charge carrier dynamics, and photovoltaic performance in model binary and ternary blend systems having a wide bandgap donor polymer, a fullerene, and a promising NFA. We show that optimal PC71BM incorporation in a PBDB-TF:ITIC-Th binary system matrix retains the original π-face-on orientation, ITIC-Th crystallinity and BHJ film crystallite dimensions, and reduces film upper surface ITIC-Th segregation. Such morphology changes together simultaneously increase hole (μh) and electron (μe) mobilities, facilitate light-activated ITIC-Th to PC71BM domain electron delocalization, reduce free charge carrier (FC) bimolecular recombination (BR) within PBDB-TF:ITIC-Th mixed regions, and increase FC extraction pathways viaPBDB-TF:PC71BM pairs. The interplay of these effects yields significantly enhanced inverted cell short-circuit current density (JSC), fill factor (FF), and PCE. Unexpectedly, we also find that excessive PC71BM in the PBDB-TF:ITIC-Th binary system alters the PBDB-TF orientation to π-edge-on, increases large scale PC71BM-rich aggregations and BHJ upper surface PC71BM composition. Further, these morphology changes increase parasitic decay processes such as intersystem crossing from photoexcited PC71BM, compromising the JSC, FF, and PCE metrics. ITIC-Th X-ray diffraction reveals a unique sidechain-dominated molecular network with previously unknown sidechain-end group stacking, rationalizing the STEM and GIWAXS results, photophysics, and the high μe. DFT computation reveals charge transfer networks within ITIC-Th crystallites, supporting excited-state electron delocalization from ITIC-Th to PC71BM. This structure–property understanding leads to a newly reported NFA blend with PCE near 17%.
Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Brookhaven National Laboratory (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II); Energy Frontier Research Centers (EFRC) (United States). Center for Light Energy Activated Redox Processes (LEAP); Northwestern Univ., Evanston, IL (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); Stanford Univ., CA (United States); Univ. of California, Oakland, CA (United States)
Sponsoring Organization:
Qatar National Research Foundation; US Department of the Navy, Office of Naval Research (ONR); USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC02-05CH11231; AC02-76SF00515; SC0001059; SC0012704
OSTI ID:
2419588
Alternate ID(s):
OSTI ID: 1957848
Journal Information:
Energy & Environmental Science, Journal Name: Energy & Environmental Science Journal Issue: 3 Vol. 16; ISSN 1754-5692
Publisher:
Royal Society of ChemistryCopyright Statement
Country of Publication:
United States
Language:
English

References (72)

Electron Transport in a Methanofullerene journal January 2003
Rylene and Related Diimides for Organic Electronics journal December 2010
An Electron Acceptor Challenging Fullerenes for Efficient Polymer Solar Cells journal January 2015
A Large-Bandgap Conjugated Polymer for Versatile Photovoltaic Applications with High Performance journal July 2015
Achieving High-Performance Ternary Organic Solar Cells through Tuning Acceptor Alloy journal December 2016
Progress in Understanding Degradation Mechanisms and Improving Stability in Organic Photovoltaics journal December 2016
Ternary Polymer Solar Cells based on Two Acceptors and One Donor for Achieving 12.2% Efficiency journal November 2016
Achieving Highly Efficient Nonfullerene Organic Solar Cells with Improved Intermolecular Interaction and Open-Circuit Voltage journal March 2017
Two Well-Miscible Acceptors Work as One for Efficient Fullerene-Free Organic Solar Cells journal May 2017
Design of a New Small‐Molecule Electron Acceptor Enables Efficient Polymer Solar Cells with High Fill Factor journal October 2017
Single‐Junction Organic Photovoltaic Cell with 19% Efficiency journal August 2021
Achieving 19% Power Conversion Efficiency in Planar‐Mixed Heterojunction Organic Solar Cells Using a Pseudosymmetric Electron Acceptor journal July 2022
Binary Organic Solar Cells Breaking 19% via Manipulating the Vertical Component Distribution journal July 2022
Fluorinating π‐Extended Molecular Acceptors Yields Highly Connected Crystal Structures and Low Reorganization Energies for Efficient Solar Cells journal May 2020
17.1 %‐Efficient Eco‐Compatible Organic Solar Cells from a Dissymmetric 3D Network Acceptor journal December 2020
Building Blocks for High‐Efficiency Organic Photovoltaics: Interplay of Molecular, Crystal, and Electronic Properties in Post‐Fullerene ITIC Ensembles journal September 2019
Chemically tailored molecular surface modifiers for efficient and stable perovskite photovoltaics journal March 2021
A new hybrid exchange–correlation functional using the Coulomb-attenuating method (CAM-B3LYP) journal July 2004
Hole (donor) and electron (acceptor) transporting organic semiconductors for bulk-heterojunction solar cells journal September 2020
Single-Junction Organic Solar Cell with over 15% Efficiency Using Fused-Ring Acceptor with Electron-Deficient Core journal April 2019
Ternary organic solar cells based on non-fullerene acceptors: A review journal March 2021
Molecular Insight into Efficient Charge Generation in Low-Driving-Force Nonfullerene Organic Solar Cells journal March 2022
Microcrystal Electron Diffraction for Molecular Design of Functional Non-Fullerene Acceptor Structures journal January 2021
Small Molecule Acceptor and Polymer Donor Crystallinity and Aggregation Effects on Microstructure Templating: Understanding Photovoltaic Response in Fullerene-Free Solar Cells journal May 2017
Enhancing Indacenodithiophene Acceptor Crystallinity via Substituent Manipulation Increases Organic Solar Cell Efficiency journal November 2017
Stable Postfullerene Solar Cells via Direct C–H Arylation Polymerization. Morphology–Performance Relationships journal May 2019
Recent Advances in Bulk Heterojunction Polymer Solar Cells journal August 2015
Organic and Polymeric Semiconductors Enhanced by Noncovalent Conformational Locks journal July 2017
Bulk Heterojunction Solar Cells: Morphology and Performance Relationships journal May 2014
Combining Electron-Neutral Building Blocks with Intramolecular “Conformational Locks” Affords Stable, High-Mobility P- and N-Channel Polymer Semiconductors journal June 2012
Crystallography, Morphology, Electronic Structure, and Transport in Non-Fullerene/Non-Indacenodithienothiophene Polymer:Y6 Solar Cells journal July 2020
Systematic Merging of Nonfullerene Acceptor π-Extension and Tetrafluorination Strategies Affords Polymer Solar Cells with >16% Efficiency journal April 2021
High-Performance Electron Acceptor with Thienyl Side Chains for Organic Photovoltaics journal March 2016
Molecular Optimization Enables over 13% Efficiency in Organic Solar Cells journal May 2017
Fluorination Effects on Indacenodithienothiophene Acceptor Packing and Electronic Structure, End-Group Redistribution, and Solar Cell Photovoltaic Response journal January 2019
Photovoltaic Blend Microstructure for High Efficiency Post-Fullerene Solar Cells. To Tilt or Not To Tilt? journal August 2019
Theoretical Characterization of the PC 60 BM:PDDTT Model for an Organic Solar Cell journal October 2011
Ultrafast Conformational Dynamics of Electron Transfer in ExBox 4+ ⊂Perylene journal November 2013
Transient Absorption Imaging of P3HT:PCBM Photovoltaic Blend: Evidence For Interfacial Charge Transfer State journal April 2011
Intensity Dependence of Current–Voltage Characteristics and Recombination in High-Efficiency Solution-Processed Small-Molecule Solar Cells journal April 2013
A high-mobility electron-transporting polymer for printed transistors journal January 2009
The role of spin in the kinetic control of recombination in organic photovoltaics journal August 2013
Silicon heterojunction solar cell with interdigitated back contacts for a photoconversion efficiency over 26% journal March 2017
Crystalline silicon solar cells: Better than ever journal May 2017
A general relationship between disorder, aggregation and charge transport in conjugated polymers journal August 2013
Polymer solar cells with enhanced fill factors journal August 2013
Delocalization of exciton and electron wavefunction in non-fullerene acceptor molecules enables efficient organic solar cells journal August 2020
Non-fullerene acceptors with branched side chains and improved molecular packing to exceed 18% efficiency in organic solar cells journal May 2021
Quantitative relations between interaction parameter, miscibility and function in organic solar cells journal February 2018
Single-junction organic solar cells with over 19% efficiency enabled by a refined double-fibril network morphology journal May 2022
The role of charge recombination to triplet excitons in organic solar cells journal September 2021
Fullerene derivative acceptors for high performance polymer solar cells journal January 2011
Electronic couplings and rates of excited state charge transfer processes at poly(thiophene- co -quinoxaline)–PC 71 BM interfaces: two- versus multi-state treatments journal January 2019
Effect of the chlorine substitution position of the end-group on intermolecular interactions and photovoltaic performance of small molecule acceptors journal January 2020
Fine-tuning of side-chain orientations on nonfullerene acceptors enables organic solar cells with 17.7% efficiency journal January 2021
Progress and prospects of the morphology of non-fullerene acceptor based high-efficiency organic solar cells journal January 2021
Non-fullerene acceptors with direct and indirect hexa-fluorination afford >17% efficiency in polymer solar cells journal January 2022
Balanced basis sets of split valence, triple zeta valence and quadruple zeta valence quality for H to Rn: Design and assessment of accuracy journal January 2005
Soft x-ray scattering facility at the Advanced Light Source with real-time data processing and analysis journal April 2012
Density‐functional thermochemistry. III. The role of exact exchange journal April 1993
Closely packed, low reorganization energy π-extended postfullerene acceptors for efficient polymer solar cells journal August 2018
Advances in molecular quantum chemistry contained in the Q-Chem 4 program package journal September 2014
Theory of space-charge-limited current enhanced by Frenkel effect journal February 1970
Electron-Hole Recombination in Germanium journal July 1952
Statistics of the Recombinations of Holes and Electrons journal September 1952
Electrical characteristics and efficiency of single-layer organic light-emitting diodes journal November 1998
Recombination in polymer-fullerene bulk heterojunction solar cells journal December 2010
Nika : software for two-dimensional data reduction journal March 2012
Quick AS NEXAFS Tool ( QANT ): a program for NEXAFS loading and analysis developed at the Australian Synchrotron journal January 2016
Ultrafast Long-Range Charge Separation in Organic Semiconductor Photovoltaic Diodes journal December 2013
Bimolecular Recombination in Organic Photovoltaics journal April 2014
Near-transform-limited visible and near-IR femtosecond pulses from optical parametric amplification using Type II β-barium borate journal January 1995


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