Theoretical study on organic dyes with tunable pi-spacers for dye-sensitized solar cells: Inspired by the organic polymer photovoltaics

Abstract

We present the theoretical investigation on tuning pi-spacers in D-pi-A organic dyes for dye-sensitized solar cells (DSSCs). The validity of three series of conjugate units (12 types) conventionally used in polymer photovoltaics are utilized as the pi-spacers of organic dyes. Our results indicate that the extension of pi conjugation can efficiently improve the absorption intensity. The absorption spectra red-shifts is because the increased pi-spacers significantly destabilize the highest occupied molecular orbital level, whereas the lowest unoccupied molecular orbital level has negligible changed. Our simulation is expected to assist the design high performance dyes for dye-sensitized solar cells applications.