Abstract
We designed a series of organic dyes based on two triphenylamine units (electron donors), pyrrole/thiophene (pi-bridge) and N-substituted alkyl thiobarbituric acid (electron acceptors) to construct the D-pi-A-D photosensitizer systems. The electronic structures and photophysical properties of the sensitizers were investigated by density functional theory (DFT) and time-dependent DFT (TD-DFT). The potential use of the dyes as photosensitizers in DSSCs was explored by calculating the light harvesting efficiency (LHE), electrons driving force injection (Delta G(inject)), the open-circuit photovoltage (V-OC), and surface interaction with semiconductor (TiO2). From alkyl-substituted sensitizers, N-ethyl derivatives TPAA3 and TPAB3 performance for Delta G(inject) (-1.69 and -1.65 eV) and V-OC (1.43, and 1.11 eV) was superior to the other dyes. In addition, the anchoring ability of the N-substituted alkyl derivatives was higher than the cyanoacrylic dyes.