Synthesis and applications of novel low bandgap star-burst molecules containing a triphenylamine core and dialkylated diketopyrrolopyrrole arms for organic photovoltaics
作者:Duryodhan Sahu、Chia-Hua Tsai、Hung-Yu Wei、Kuo-Chuan Ho、Feng-Chih Chang、Chih-Wei Chu
DOI:10.1039/c2jm16760c
日期:——
In this study, we used facile synthetic routes to construct two well-defined starburst donor/acceptor conjugated small molecules with broad absorption features; in TPAKP-2 and TPAKP-3, triphenylamine (TPA) moieties served as electron donor core units and dialkylated diketopyrrolopyrrole (DKP) moieties with symmetrical thiophene units served as electron acceptors, in 1 : 2 and 1 : 3 ratios, respectively. Our investigation of the photophysical properties indicated that the absorption bands of TPAKP-2, and TPAKP-3 extended up to 793 nm, with low optical band gaps of 1.56 and 1.65 eV respectively. Under illumination with AM 1.5 white light (100 mW cm−2), we investigated the performance of bulk heterojunction (BHJ) photovoltaic devices incorporating an active layer of an electron-donor small molecule (TPAKP-2 or TPAKP-3) blended with an electron acceptor: [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) or [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) at various weight ratios. The photovoltaic device containing the donor TPAKP-3 and the acceptor PC71BM at a 1 : 3 weight ratio exhibited the best power conversion efficiency (1.81%), with an open circuit voltage of 0.66 V, a short circuit current density of 7.93 mA cm−2, and a fill factor of 34.7%.
在这项研究中,我们使用简便的合成路线构建了两种具有广泛吸收特征的明确的星爆供体/受体共轭小分子;在TPAKP-2和TPAKP-3中,三苯胺(TPA)部分作为电子供体核心单元,具有对称噻吩单元的二烷基化二酮吡咯并吡咯(DKP)部分作为电子受体,比例分别为1 : 2和1 : 3。我们对光物理性质的研究表明,TPAKP-2和TPAKP-3的吸收带延伸至793 nm,光学带隙分别为1.56和1.65 eV。在 AM 1.5 白光 (100 mW cm−2) 照明下,我们研究了体异质结 (BHJ) 光伏器件的性能,该器件结合了电子给体小分子(TPAKP-2 或 TPAKP-3)的活性层,并与电子受体:各种重量比的[6,6]-苯基-C61-丁酸甲酯(PC61BM)或[6,6]-苯基-C71-丁酸甲酯(PC71BM)。以1 : 3的重量比包含供体TPAKP-3和受体PC71BM的光伏器件表现出最佳的功率转换效率(1.81%),开路电压为0.66 V,短路电流密度为7.93 mA cm− 2、填充因子为34.7%。