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Indexed by:期刊论文

Date of Publication:2016-10-01

Journal:SYNTHETIC METALS

Included Journals:SCIE、EI、Scopus

Volume:220

Page Number:448-454

ISSN No.:0379-6779

Key Words:Isoindigo; Small molecules solar cells; Narrow band gap; Bulk heterojunction; Solution-processed

Abstract:Isoindigo, one of the latest reported amide-based electron-accepting units, was introduced into two new D-pi-A-pi-D typed organic small molecules with triphenylamine as electron-donating unit for organic solar cells. Both (TPAEB)(2)iI and (TPACB)(2)iI possess narrow band gaps of 1.57 and 1.71 eV, respectively. Notably, (TPACB)(2)iI with 2-phenylacrylonitrile as pi-bridge exhibited a high open-circuit voltage of 1.06 V and an improved power conversion efficiency of 3.57%, which is the best performance for isoindigo-triphenylandne based solution-processed organic photovoltaic devices so far. The high open-circuit voltage is primarily attributed to its higher electrochemical oxidation potential by molecular design. The relatively higher photovoltaic performance of (TPACB)(2)iI-based device relative to (TPAEB)(2)iI is shown to originate from the reasonably higher hole-transporting capacity, more optimized active layer morphology and higher degree of crystallinity. These results indicate that isoindigo-based small molecules are a kirid of promising photovoltaic materials. (C) 2016 Elsevier B.V. All rights reserved.