Temperature-Dependent and Aggregation-Breaking Strategy for Benzodifuran-Constructed Organic Solar Cells
Temperature-Dependent and Aggregation-Breaking Strategy for Benzodifuran-Constructed Organic Solar Cells
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苯并二呋喃构建的有机太阳能电池的温度依赖性和聚集破坏策略
DOI：
10.1002/solr.201900159
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发表时间：
2019
期刊：
影响因子：
7.9
通讯作者：
Yang Renqiang
中科院分区：
文献类型：
--
作者：
Qiao Shanlin;Li Xiaoming;Wang Huan;Zhang Boying;Li Zheng;Zhao Jia;Chen Weichao;Yang Renqiang
基于苯并[1,2‐b:4,5‐b ']二噻吩（BDT）单元的半导体聚合物的研究已经取得了很大的进展，而类似核心苯并[1,2‐b:4,5‐b ']二呋喃（BDF）具有类似的扩展平面结构，其电子结构在光伏系统中的发展较少。本文合成了一种新型的BDF核基共聚物PBDFTz - SBP，该共聚物具有两个2D延伸的联苯侧链，与BDT基聚合物相比，聚合物段畸变较小，分子间π - π相互作用强。利用该聚合物，提出了一种抑制聚合物段自聚集趋势的聚破策略，获得了适当的相分离，形成了有利于电荷传输的双连续互穿网络。结果表明，当自旋涂层溶液温度为120°C时，PBDTTz - SBP:ITIC器件在开路电压（VOC）为0.89 V、短路电流密度（JSC）为18.56 mA cm−2、填充系数（FF）为75.19%的情况下，功率转换效率（PCE）为12.42%，即使在优化条件下也高于PBDTTz - SBP:ITIC器件。该策略可能是BDF单元构建供体(D) -受体(a)型聚合物的一个很好的选择，并超越相应的BDT基光伏材料，获得最先进的pce。
Great efforts have been devoted to semiconductive polymers based on the benzo[1,2‐b:4,5‐b’]dithiophene (BDT) unit, and great progress has been achieved in organic solar cells, whereas the analogue core benzo[1,2‐b:4,5‐b’]difuran (BDF) has the similar extended planar structure, and the electronic structure gets less development in the photovoltaic system. Herein, a novel BDF core‐based copolymer PBDFTz‐SBP is synthesized, which decorates with two 2D extended biphenyl side chains and shows a relatively small polymer segments distortion and strong intermolecularπ–πinteraction in relation to the BDT‐based polymer. Using this polymer, an aggregation‐breaking strategy to suppress the trend of self‐aggregation of polymers’ segment is proposed, which obtains an appropriate phase separation and forms favorable bicontinuous interpenetrating networks for charge transport. It is found that PBDFTz‐SBP:ITIC achieves an excellent power‐conversion efficiency (PCE) of 12.42% with an open‐circuit voltage (VOC) of 0.89 V, a short‐circuit current density (JSC) of 18.56 mA cm−2, and a high fill factor (FF) of 75.19% when the spin‐coating solution is 120 °C, which is higher than that of PBDTTz‐SBP:ITIC‐based devices even under optimized conditions. This proposed strategy may be a good choice for the BDF unit to construct the donor (D)–acceptor (A) type polymers and surpass the counterpart BDT‐based photovoltaic materials and obtain a state‐of‐the‐art PCEs.