Critical Role of Molecular Electrostatic Potential on Charge Generation in Organic Solar Cells

Yao, Huifeng; Qian, Deping; Zhang, Hao; Qin, Yunpeng; Xu, Bowei; Cui, Yong; Yu, Runnan; Gao, Feng; Hou, Jianhui

doi:10.1002/cjoc.201800015

Cited by 180 publications

(154 citation statements)

References 24 publications

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“…In this study, two materials with similar chemical structures, SA‐4 (2‐(thiophen‐2‐ylmethylene)‐1 H ‐indene‐1,3(2 H )‐dione) and SA‐7 (( Z )‐2‐(3‐oxo‐2‐(thiophen‐2‐ylmethylene)‐2,3‐dihydro‐1 H ‐inden‐1‐ylidene)malononitrile ( Figure a), and different volatilities were synthesized and applied as solid additives in NF‐PSCs based on a chlorinated polymeric donor (PBDB‐TCl) and a fluorinated NF acceptor (IT‐4F) . Instead of pursuing higher PCE values, we aimed to investigate the working mechanisms of solid additives with different volatilities and their effects on the photovoltaic performances of PSCs.…”

Section: Photovoltaic Parameters For Pbdb‐tcl:it‐4f Based Devices Promentioning

confidence: 99%

Enhanced π–π Interactions of Nonfullerene Acceptors by Volatilizable Solid Additives in Efficient Polymer Solar Cells

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Fine‐tuning of the nanoscale morphologies of the active layers in polymer solar cells (PSCs) through various techniques plays a vital role in improving the photovoltaic performance. However, for emerging nonfullerene (NF) PSCs, the morphology optimization of the active‐layer films empirically follows the methods originally developed in fullerene‐based blends and lacks systematic studies. In this work, two solid additives with different volatilities, SA‐4 and SA‐7, are applied to investigate their influence on the morphologies and photovoltaic performances of NF‐PSCs. Although both solid additives effectively promote the molecular packing of the NF acceptors, due to the higher volatility of SA‐4, the devices processed with SA‐4 exhibit a power conversion efficiency of 13.5%, higher than that of the control devices, and the devices processed with SA‐7 exhibit poor performances. Through a series of detailed morphological analyses, it is found that the volatilization of SA‐4 after thermal annealing is beneficial for the self‐assembly packing of acceptors, while the residuals due to the incomplete volatilization of SA‐7 have a negative effect on the film morphology. The results delineate the feasibility of applying volatilizable solid additives and provide deeper insights into the working mechanism, establishing guidelines for further material design of solid additives.

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Section: Photovoltaic Parameters For Pbdb‐tcl:it‐4f Based Devices Promentioning

confidence: 99%

Enhanced π–π Interactions of Nonfullerene Acceptors by Volatilizable Solid Additives in Efficient Polymer Solar Cells

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“…To tackle this issue, non‐fullerene acceptors (NFAs) with tunable energy and various structure have emerged and achieved rapid progress . Figure summarized the obtained PCE under varied V OC values (Figure a) and the relationship between V OC and E loss (Figure b), where over fifty reported OSCs are involved, related references have been listed in Supporting Information.…”

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confidence: 99%

Efficient Organic Solar Cells with a High Open‐Circuit Voltage of 1.34 V

et al. 2019

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Summary of main observation and conclusion One of the most important challenges that hinders the power conversion efficiencies (PCEs) of organic solar cells (OSCs) is the modest open‐circuit voltages (VOC) due to large energy losses. The large driving force during for charge generation and the non‐radiative recombination are the main causes of energy losses. To maximize the VOC of OSCs, herein, we modulate the end‐groups and design a non‐fullerene acceptor ITCCM‐O, which shows a bandgap of 2.0 eV. By blending a polymer donor named J52, the device demonstrates a PCE of 5.5% with an outstanding VOC of 1.34 V, which is the highest value for single‐junction OSCs over 5% PCEs. The high VOC is benefited from 1) the negligible driving force for charge transfer, and 2) the suppressed non‐radiative recombination loss, as low as 0.22 V.

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“…[4][5][6] Benefiting from the great efforts devoted to the design of new materials, [7][8][9][10][11][12][13] optimization of the blend morphology, [14][15][16][17][18] understanding the charge generation mechanism, [19][20][21][22][23][24][25][26] significant progress has been achieved in the last few years. [4][5][6] Benefiting from the great efforts devoted to the design of new materials, [7][8][9][10][11][12][13] optimization of the blend morphology, [14][15][16][17][18] understanding the charge generation mechanism, [19][20][21][22][23][24][25][26] significant progress has been achieved in the last few years.…”

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Eco‐Compatible Solvent‐Processed Organic Photovoltaic Cells with Over 16% Efficiency

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inorganic photovoltaic cells based on crystal-silicon, the solution processability of OPV cells makes it suitable for the largescale solution production at room temperature via the roll-to-roll method, which promises low-cost and large area device fabrication onto flexible substrates. [4][5][6] Benefiting from the great efforts devoted to the design of new materials, [7][8][9][10][11][12][13] optimization of the blend morphology, [14][15][16][17][18] understanding the charge generation mechanism, [19][20][21][22][23][24][25][26] significant progress has been achieved in the last few years. Recently, the power conversion efficiencies (PCEs) of OPV cells have surpassed ≈15%. [27][28][29] However, the devices with cutting-edge performance are fabricated using highly toxic solvents like chlorinated and/or aromatic solvents, which is not adaptable for large-scale production and becoming a severe problem that hinders the mass production of the OPV cells. Therefore, the material design of OPV materials should take both the efficiency and processability into consideration.At present, the commonly used processing solvents for high-performance OPV materials are chlorobenzene (CB) and chloroform (CF), as they possess excellent dissolving capability of the highly conjugated structures. [30][31][32] Over the last few years, the design and application of nonfullerene acceptors (NFAs) have achieved 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 cm 2 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. Organic PhotovoltaicsOrganic photovoltaic (OPV) cells consisting of organic layers as photoactive materials are one of the most promising next-generation photovoltaic technologies to harvest clean and renewable solar energy. [1][2][3] When compared with the conventional

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Critical Role of Molecular Electrostatic Potential on Charge Generation in Organic Solar Cells

Cited by 180 publications

References 24 publications

Enhanced π–π Interactions of Nonfullerene Acceptors by Volatilizable Solid Additives in Efficient Polymer Solar Cells

Enhanced π–π Interactions of Nonfullerene Acceptors by Volatilizable Solid Additives in Efficient Polymer Solar Cells

Efficient Organic Solar Cells with a High Open‐Circuit Voltage of 1.34 V

Eco‐Compatible Solvent‐Processed Organic Photovoltaic Cells with Over 16% Efficiency

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