先进有机功能材料研究组知识库

Two new acceptor-donor-acceptor (A-D-A) type small molecules DCAO3TIDT and DCNR3TIDT, with 4,4,9,9-tetrakis(4-(dodecyloxy) phenyl)-4,9-dihydro-s-indaceno-[1,2-b:5,6-b']dithiophene (IDT) as the core group and 2-ethylhexyl cyanoacetate (CAO) and 2-(1,1-dicyanomethylene)-3-octyl rhodanine (CNR) as different end-capped blocks, have been designed and synthesized. Both of them have been employed as donor for solution-processed bulk hetero-junction (BHJ) organic solar cells (OSCs). The two compounds showed deep highest occupied molecular orbital (HOMO) energy levels (similar to-5.30 eV) and strong absorption. The DCAO3TIDT and DCNR3TIDT with PC71BM as acceptor based BHJ solar cell devices showed short circuit current density (J(sc)) of 6.93 mA/cm(2) and 8.59 mA/cm2, power conversion efficiency (PCE) of 3.34% and 4.27%, respectively, and with almost same open-circuit voltage (similar to 0.93 V), under the illumination of AM 1.5 G, 100 mW/cm(2). The high Jsc for DCNR3TIDT could result from its wider and red-shifted absorption than that of DCAO3TIDT, which was probably induced by the end-capped block rhodanine derivative. The results demonstrate that the end group would be taken into full account when designing new solution-processed small molecules, which is an important factor to determine their photovoltaic properties. (C) 2015 Elsevier B.V. All rights reserved.