Organic dyes containing fused acenes as building blocks: Optical, electrochemical and photovoltaic properties

Two D-pi-A dyes based on fused acenes (carbazole, cyclopenta[2,1-b:3,4-b']dithiophene (CPDT) and dithieno[3,2-b:2',3'-d]pyrrole (DTP)) were synthesized, characterized using UV-vis absorption spectroscopy and electrochemistry, density function theory (DFT') calculations, and used as sensitizers in dye sensitized solar cells (DSSCs). The two sensitizers were compared thoroughly over physicochemical properties and DSSC performance. Although the DTP dye has slightly blue-shifted and weaker incident photon-to-collected electron (IPCE) conversion efficiency responses, the much increased open-circuit photovoltage values and improved charge-transfer kinetics relative to the CPDT systems result in superior power conversion efficiencies. This work reveals the potential of DTP as a bridge in the design of sensitizers. (C) 2017 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.