DFT and TD-DFT study of substituent effects on structure, spectroscopic and photoelectric characteristics of D-A dyes for solar cells

Abstract

To study the structure, photophysical and photoelectric properties of chlorophyll derivatives, the chlorophyll derivative dyes (CHL-1 and CHL-6) were investigated to exploit their utility in solar cells. The two experimental dye systems were simulated using DFT and TD-DFT, and optimization of the structure, absorption spectroscopy, chemical parameters, electron transfer, and dye regeneration processes were studied to analyze their different performance. Furthermore, a functional group substitution strategy was adopted to improve PCE, and the electron-withdrawing groups were introduced into the acceptor group of CHL-6 to design new chlorophyll derivative molecules, in which the high efficiency for designed molecule CN-1 is 1.19 times that of the experimental molecule CHL-6. This study provides insights into the optoelectronic properties of chlorophyll derivatives, and introducing specific electron-withdrawing groups in the acceptor fraction helps to improve photoelectric efficiency.