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β ‐Functionalized Imidazole‐Fused Porphyrin‐Donor‐Based Dyes: Effect of π‐Linker and Acceptor on Optoelectronic and Photovoltaic Properties
Author(s) -
Bodedla Govardhana Babu,
Wang Hongda,
Chang Shuai,
Chen Song,
Chen Tao,
Zhao Jianzhang,
Wong WaiKwok,
Zhu Xunjin
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201702652
Subject(s) - photochemistry , acceptor , linker , dye sensitized solar cell , porphyrin , phenylene , imidazole , thiophene , chemistry , cyclic voltammetry , materials science , electrochemistry , electrolyte , organic chemistry , electrode , physics , polymer , computer science , condensed matter physics , operating system
We have designed and synthesized three new donor (D)‐linker (π)‐acceptor (A) type β ‐functionalized imidazole‐fused porphyrins, 4 a ‐ 4 c by grafting the acceptor such as cyanoacrylic acid/carboxylic acid at 2 nd position of imidazole fused to the β,β ′ edge of porphyrin donor via π‐linker such as thiophene/phenylene and examined them as sensitizers for dye‐sensitized solar cells (DSSCs). The structure‐activity relationships of the dyes are systematically investigated by using absorption spectroscopy, cyclic voltammetry, and density functional theory calculations. Dyes, 4 a and 4 b possessing cyanoacrylic acid acceptor exhibited broadened Soret bands compared with that of dye 4 c containing carboxylic acid acceptor, which led to good light‐harvesting properties and thereby broader IPCE curves. The DSSCs of the dye, 4 a possessing thiophene linker and cyanoacrylic acid acceptor exhibit higher power conversion efficiency than the analogous dyes, 4 b and 4 c with phenylene π‐linker and cyanoacrylic acid or carboxylic acid acceptor. The hike in the efficiency comes from the increased short‐circuit current and open‐circuit voltage due to reduced dye aggregation. Electrochemical impedance spectroscopy studies reveal that the life‐time of the injected electrons in the conduction band of TiO 2 and charge recombination rate at the TiO 2 /dye/electrolyte interface mainly dependent on nature of π‐linker and acceptor of the dyes.