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Molecular Engineering of Boryl Oxasmaragdyrins through Peripheral Modification: Structure–Efficiency Relationship
Author(s) -
Mane Sandeep B.,
Hung ChenHsiung
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201405856
Subject(s) - photovoltaic system , dye sensitized solar cell , molecular engineering , porphyrin , absorption (acoustics) , acceptor , photochemistry , materials science , energy conversion efficiency , chemistry , optoelectronics , nanotechnology , electrical engineering , physics , electrode , composite material , condensed matter physics , electrolyte , engineering
Expanded porphyrins with the absorption profile down to the infrared region through increased π‐conjugation are suitable candidates for a low energy sensitizer. Oxasmaragdyrin boron complexes, a class of aromatic‐core‐modified expanded porphyrin with 22 π‐electrons, have been recently utilized as an efficient low energy sensitizer in dye‐sensitized solar cells. In this paper, we have prepared a series of eight novel boryl oxasmaragdyrins through molecular engineering on the periphery and their overall photovoltaic performances in dye‐sensitized solar cells are evaluated. With the help of photophysical, electrochemical, and photovoltaic studies, it is revealed that molecular structure, especially the number and position of the donor–acceptor groups play a pivotal role in their photovoltaic performance. Presence of the two well‐separated split Soret bands in the 400–500 nm region of UV/Vis spectrum ensures broader coverage of absorption wavelengths. Even though the two‐anchoring‐group dyes ( SM5 – SM8 ) bind strongly to TiO 2 compared to one‐anchoring‐group dyes ( SM1 – SM4 ), the latter have superior photovoltaic performance than the former. Dye SM1 , with two hexyloxyphenyl donors and one carboxylic acid anchor showed the best overall conversion efficiency of 4.36 % ( J SC =10.91 mA cm −2 ; V OC =0.59 V; FF =0.68). This effective modulation of photovoltaic performance through structural engineering of the dyes will serve as a guideline for the future design of efficient low energy light‐harvesting sensitizers.