Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2017-05-01

Journal: DYES AND PIGMENTS

Included Journals: EI、SCIE

Volume: 140

Page Number: 203-211

ISSN: 0143-7208

Key Words: Benzothiadiazole; Ethynyl; Carbazole; Triphenylamine; Photovoltaic performance; Bulk heterojunction

Abstract: Two novel D-pi-A-pi-D-typed dioctyloxy-benzothiadiazole (DOBT)-based small molecules (SMs), TPAEDOBT and CZEDOBT, were designed and synthesized, consisting of ethynyl as pi-linkage, besides, incorporating triphenylamine (TPA) and alkylated-carbazole (Cz) as terminal electron-donating units respectively. Single-bond compounds, TPADOBT and CZDOBT, were designed as references to fully investigate their photovoltaic (PV) performance of solution-processed devices. As expected, the PV properties were finely tuned via molecular design with ethynyl-linker and terminal electron-donating units. Among them, the best power conversion efficiency (PCE) of 3.21% was obtained for TPAEDOBT-based device due to triple-bond effect and high hole-mobility. Most importantly, a remarkably increased open-circuit voltage (Voc) of 1.06 V was achieved for CZEDOBT-based device due to synergistic effect of ethynyl-linker with electron-withdrawing character and Cz unit with the relatively weakened electron donating ability, which is among the earliest report for DOBT-Cz based SMs with high Voc so far. These results provide an important guide for rational design of novel SMs PV materials. (C) 2017 Elsevier Ltd. All rights reserved.