The synthesis and photovoltaic properties of A–D–A-type small molecules containing diketopyrrolopyrrole terminal units
作者:Ling Zhang、Shaohang Zeng、Lunxiang Yin、Changyan Ji、Kechang Li、Yanqin Li、Yue Wang
DOI:10.1039/c2nj40963a
日期:——
A series of novel AâDâA structured small molecule photovoltaic (PV) materials [CZ(TDPP)2, DPA(TDPP)2, PTZ(TDPP)2 and FL(TDPP)2] with diketopyrrolopyrrole (DPP) as an electron-withdrawing group were synthesized and characterized. These small molecular donors exhibit excellent solubility in common organic solvents. The density functional theory (DFT) calculations demonstrated the intramolecular charge transfer (ICT) behavior of the synthesized PV materials and an efficient charge separation was observed by a fluorescence quenching experiment. In addition, their photophysical and electrochemical properties show that they harvest sunlight over the entire visible spectrum range and keep appropriate energy levels to satisfy the requirement of solution-processable OSCs. Therefore, we explored the PV properties of the synthesized donors by fabricating BHJ solar cells with a typical structure of ITO/PEDOT:PSS/Donors:PC61BM/LiF/Al. Among them, CZ(TDPP)2 revealed a promising performance in PV devices with a power conversion efficiency (PCE) of 1.50%, along with an open-circuit voltage (VOC) of 0.66 V, a short-circuit current density (JSC) of 4.12 mA cmâ2, and a fill factor (FF) of 0.44, under an illumination of AM 1.5G (80 mW cmâ2).
合成并表征了一系列新型A–D–A结构的小分子光伏材料[CZ(TDPP)2、DPA(TDPP)2、PTZ(TDPP)2和FL(TDPP)2],其中二氟吡咯吡咯(DPP)作为电子吸收基团。这些小分子供体在常见有机溶剂中表现出优异的溶解性。密度泛函理论(DFT)计算展示了合成的光伏材料的分子内电荷转移(ICT)行为,通过荧光猝灭实验观察到了高效的电荷分离。此外,它们的光物理和电化学特性表明,这些材料能够在整个可见光谱范围内利用阳光,并保持合适的能级,以满足可溶液加工有机太阳能电池(OSCs)的要求。因此,我们通过构建具有典型结构的BHJ太阳能电池(ITO/PEDOT:PSS/供体:PC61BM/LiF/Al)来探讨合成的供体的光伏性质。其中,CZ(TDPP)2在光伏器件中表现出良好的性能,功率转换效率(PCE)为1.50%,开路电压(VOC)为0.66 V,短路电流密度(JSC)为4.12 mA cm⁻²,填充因子(FF)为0.44,在AM 1.5G(80 mW cm⁻²)照射下测得。