Release Time:2019-03-13  Hits:

Indexed by: Journal Article

Date of Publication: 2016-10-01

Journal: SYNTHETIC METALS

Included Journals: Scopus、EI、SCIE

Volume: 220

Page Number: 448-454

ISSN: 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.