Novel benzo[1,2-b:4,5-b']difuran-based copolymer enables efficient polymer solar cells with small energy loss and high VOC

Gao, Yueyue; Shen, Zhitao; Tan, Furui; Yue, Gentian; Liu, Rong; Wang, Zhijie; Qu, Shengchun; Wang, Zhanguo; Zhang, Weifeng

doi:10.1016/j.nanoen.2020.104964

Cited by 56 publications

(34 citation statements)

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“…To approach the highest theoretical PCE, some difficulties should be overcome during the device preparation process. The open‐circuit voltage ( V OC ) of a solar cell depends on the difference between the donor's highest occupied molecular orbital (HOMO) and the acceptor's lowest unoccupied molecular orbital level (LUMO) and could be modified by organic molecular design 15–17 . However, it is difficult to achieve a synergistic optimization between the V OC and charge transport.…”

Section: Introductionmentioning

confidence: 99%

“…The open-circuit voltage (V OC ) of a solar cell depends on the difference between the donor's highest occupied molecular orbital (HOMO) and the acceptor's lowest unoccupied molecular orbital level (LUMO) and could be modified by organic molecular design. [15][16][17] However, it is difficult to achieve a synergistic optimization between the V OC and charge transport. Fill factor (FF) could be improved through device engineering.…”

Section: Introductionmentioning

confidence: 99%

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Optical management in organic photovoltaic devices

et al. 2021

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Due to their potentials in light-weight, flexible, and semitransparent devices, organic photovoltaics are of great significance in the field of renewable energy. However, the narrow intrinsic absorption spectrum of organic materials hinders the full utilization of solar energy. To fabricate a highly efficient opaque solar cell, it is greatly necessary to modify the optical properties of the device to improve light absorption. In addition, the growing interest in building-integrated photovoltaics drives the development of semitransparent devices. The preparation of semitransparent solar cells with excellent performance imposes high requirements on the high efficiency and appropriate visible light transmittance of effective optical management. In this review, the recent research progress of optical management in organic photovoltaics is reviewed, including the design of light-absorbing materials, the modification of different layers, adding a lighttrapping structure, and changing the light absorption capabilities of specific materials, so as to provide strategies of how to improve the performance of organic photovoltaic devices and present the prospect of the area.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optical management in organic photovoltaic devices

et al. 2021

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“…As the PC 71 BM content is further increased to 0.2 (T 0.2 ) and 0.3 wt% (T 0.3 ), however, the devices become slightly and even worse, in the latter of which V OC , J SC , and FF coincidently drop to 0.80 V, 21.9 mA cm −2 , and 57%, giving rise to an inferior efficiency of ≈10%. Clearly, these results suggest that a slight incorporation of PC 71 BM offers additional electron‐transporting paths to facilitate charge transport and collection, thus increasing both J SC and FF, accompanied by little energy loss (i.e., nearly unchanged V OC ); [ 50,51 ] yet an excessive addition can cause an increasingly rougher blend film, i.e., severe phase separation, as shown in Figure 2, which is unfavorable for exciton dissociation and charge transport. As a result, 0.1 wt% PC 71 BM addition (i.e., T 0.1 blend) yields an optimal film morphology, which is the most beneficial for device enhancement.…”

Section: Resultsmentioning

confidence: 97%

“…As shown in Table S4, Supporting Information, μ h / μ e of optimal T 0.1 attains a most balanced transport value of 0.46, which is responsible for superior FF. [ 51 ]…”

Section: Resultsmentioning

confidence: 99%

Developing Halogen‐Free Polymer Donors for Efficient Nonfullerene Organic Solar Cells by Addition of Highly Electron‐Deficient Diketopyrrolopyrrole Unit

Xie

Tang

et al. 2021

Solar RRL

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High‐performance polymer donors when paired with nonfullerene acceptors are mainly limited to flanking halogenated benzodithiophene (BDT)‐based π‐conjugated copolymers, which however involve complex synthetic procedures. Herein, a series of halogen‐free polymer donors that link BDT moiety with two highly electron‐deficient benzodithiophene‐dione (BDD) and diketopyrrolopyrrole (DPP) units with various molar ratios is developed. Compared with the benchmark PBDB‐T donor containing BDD unit, additional incorporation of a stronger electron‐negative DPP unit markedly lowers frontier molecular orbital levels and extends optical absorption, potentially leading to simultaneously enhanced VOC and JSC in organic solar cells. A remarkable power conversion efficiency (PCE) of 10.28% is thus obtained in the optimal P75 (BDD : DPP = 3:1 mol%) and Y6 blend cells in comparison with the reference PBDB‐T:Y6 (9.20%). A slight addition of PC71BM into the blend is found to further generate finer phase‐separated domains and thus increase the best efficiency up to 12.20%. The subtly critical roles of PC71BM are determined by transient absorption measurements on both thin‐film and in situ devices to be the prolonged free charge carrier lifetime and the shallow charge transfer states, which enhance JSC and fill factor in the device, respectively.

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“…材料中, 噻吩共轭链上全氯(即四氯)取代的 PBT4Cl-Bz 表现出最低的 E HOMO , 基于 PBT4Cl-Bz/IT-4F(w/w, 1∶1, 100 nm)器件的 V oc 为 0.96 V, J sc 为 16.4 mA/cm 2 , FF 为 58.7%, PCE 为 9.25%, E loss 仅为 0.54 eV. 2020 年, 王智杰、谭付瑞等 [80] [17] [84] . 基于 PffT2-FTAZ-2DT/IEIC(w/w, 1∶ 1.5, 80 nm)器件的 V oc 明显提升至 1.00 V, 但器件性能有…”

Section: 有机太阳能工作机理unclassified

Research Advances on Benzotriazole-based Organic Photovoltaic Materials

Bai¹,

Xue²,

Wang³

et al. 2021

Acta Chimica Sinica

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Over the past two decades, organic solar cells (OSCs) have been developed rapidly with the power conversion efficiency rapidly rising from less than 5% to over 18%, which is mainly promoted by the development of various new donor and acceptor materials. As a typical electron-deficient penta-heterocycle, benzotriazoles (BTAs) derivates a variety of high-performance photovoltaic materials, including polymer donor, small-molecule donor materials, as well as non-fullerenes acceptor and polymer acceptor. Among them, the J series of polymer donors and Y series of non-fullerenes acceptors are typical examples, and thus are specially highlighted in this review. Meanwhile, molecular design strategies of those BTA-based photovoltaic materials have also been discussed. It shows that donor-acceptor (D-A) conjugated strategy is still the most efficient thus far, where A units is the BTA unit or its derivatives, and D units commonly used in BTA-based photovoltaic materials are benzodithiophene, benzodifuran, dithienosilole, indacenodithiophene, thiophene, etc. The D-A strategy is both applied for donor molecules (with the molecular structure of D-A, D-π-A-π, D-A-D-A-D, etc.), and for acceptor molecules (with the molecular structure of A-D-A, A-π-D-π-A, A-DAD-A, etc.). By adjusting their molecular structures and/or pairing of differential D and A units, various properties such as absorption band and energy levels of molecules, as well as the morphology and charge carrier mobilities in OSCs can be well controlled. Furthermore, through side-chain engineering, such as flexible side-chains (alkyl, alkoxy, alkylthiol, alkylsilyl, etc.), conjugated side-chains (substituted-thiophene or benzene, etc.), electron-withdrawing groups (F atoms, Cl atoms, dicyanomethylene, etc.), their photovoltaic properties can be further regulated. Here, this review focuses on the research progress on BTA-based photovoltaic materials and related molecular design strategies developed in recent years, and also presents perspective on its future development.

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Novel benzo[1,2-b:4,5-b']difuran-based copolymer enables efficient polymer solar cells with small energy loss and high VOC

Cited by 56 publications

References 50 publications

Optical management in organic photovoltaic devices

Optical management in organic photovoltaic devices

Developing Halogen‐Free Polymer Donors for Efficient Nonfullerene Organic Solar Cells by Addition of Highly Electron‐Deficient Diketopyrrolopyrrole Unit

Research Advances on Benzotriazole-based Organic Photovoltaic Materials

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