Rational design of cost-effective dyes for high performance dye-sensitized cells in indoor light environments

One of the important features of dye-sensitized solar cells (DSCs) is that their performance is relatively unaffected by lighting conditions, e.g., lighting angles and lighting intensity, which makes them ideal for application in indoor light environments. While most of past research on DSCs has focused on their performance under one-sun conditions, the effect of the structure of the dye on device performance under indoor lights has not been studied before. For this study, we designed a series of organic dyes with donor-π-bridge-acceptor (D-π-A) structure that can be synthesized in three reaction steps from inexpensive raw materials. The photophysical and electrochemical properties of the dyes and the device characteristics of the DSCs employing these dyes under indoor light (LED and T5 lamp, 600 lux) were investigated. In our research, the best PCE value of DSCs under LED lamps was 12.21% when TKU-6 was used as the sensitizer (70.8% of N719). Under T5 lamps, it was 13.43% when TKU-4 was used as the sensitizer (68.5% of N719). Moreover, we proposed the structural design strategies for dyes for high performance DSCs under indoor lights based on the type of π-bridge, the number of alkyl chains and the absorption spectrum of the dye.