Solution processable low bandgap diketopyrrolopyrrole (DPP) based derivatives: novel acceptors for organic solar cells
作者:Prashant Sonar、Ging-Meng Ng、Ting Ting Lin、Ananth Dodabalapur、Zhi-Kuan Chen
DOI:10.1039/b924404b
日期:——
Novel low bandgap solution processable diketopyrrolopyrrole (DPP) based derivatives functionalized with electron withdrawing end capping groups (trifluoromethylphenyl and trifluorophenyl) were synthesized, and their photophysical, electrochemical and photovoltaic properties were investigated. These compounds showed optical bandgaps ranging from 1.81 to 1.94 eV and intense absorption bands that cover a wide range from 300 to 700 nm, attributed to charge transfer transition between electron rich phenylene-thienylene moieties and the electron withdrawing diketopyrrolopyrrole core. All of the compounds were found to be fluorescent in solution with an emission wavelength ranging from 600 to 800 nm. Cyclic voltammetry indicated reversible oxidation and reduction processes with tuning of HOMO–LUMO energy levels. Bulk heterojunction (BHJ) solar cells using poly(3-hexylthiophene) (P3HT) as the electron donor with these new acceptors were used for fabrication. The best power conversion efficiencies (PCE) using 1 : 2 donor–acceptor by weight mixture were 1% under simulated AM 1.5 solar irradiation of 100 mW cm−2. These findings suggested that a DPP core functionalized with electron accepting end-capping groups were a promising new class of solution processable low bandgap n-type organic semiconductors for organic solar cell applications.
合成了新型低带隙可溶液加工二酮吡咯(DPP)基衍生物,并研究了它们的光物理、电化学和光伏特性。这些化合物显示出 1.81 至 1.94 eV 的光带隙和覆盖 300 至 700 nm 宽波长范围的强吸收带,这归因于富电子的苯基噻吩基团和抽电子的二酮吡咯核心之间的电荷转移转变。所有化合物在溶液中都具有荧光,发射波长为 600 至 800 纳米。循环伏安法表明,随着 HOMO-LUMO 能级的调整,氧化和还原过程是可逆的。利用聚(3-己基噻吩)(P3HT)作为电子给体,并使用这些新的受体制造了体异质结(BHJ)太阳能电池。在 100 mW cm-2 的模拟 AM 1.5 太阳辐照下,使用 1 : 2 供体-受体重量比混合物的最佳功率转换效率(PCE)为 1%。这些研究结果表明,与电子接受端封端基团功能化的 DPP 内核是一类很有前途的新型可溶液加工低带隙 n 型有机半导体,可应用于有机太阳能电池。