Exploring the Effect of Introducing a pi-Bridge on The Efficiency of a Perylene-Brazilein Based D-D-pi-A System: A Theoretical Perspective

摘要

We report theoretical studies on some perylene based dyes for their electron transfer properties in solar cell applications. The study involves modeling of Donor-pi-Donor-pi-Acceptor (D--D--A) systems with perylene and brazilein as the two donors, cyanoacrylic acid group as acceptor, thiophene as the pi-bridge between the brazilein and acceptor and a varying -Bridge between the two donors . The effect of introducing a pi-bridge as well as varying the pi-bridges on the efficiency of a perylene-brazilein based D-D-pi-A framework was evaluated in terms of various opto-electronic and photovoltaic parameters affecting cell efficiency. All quantum computations were carried out using Density functional theory (DFT) using 6-311G(d, p) / LanL2DZ (for I and Ti atoms) as the basis sets and B3LYP as the functional, both in the gas phase as well as solvent phase, with Gaussian 03 set of codes. We found that the sensitizers show good optical as well as photovoltaic response. The dye molecules with benzene (PB2), pyrimidine (PB7), pyrazine (PB8) and aniline (PB9) as pi-bridges exhibit better electron injection efficiencies and are hence, expected to be better sensitizers. The overall opto-electronic and transport parameters of the TiO2 - dye adsorbed systems after anchoring the dyes on the model TiO2 cluster was also studied which revealed that the dye molecules are expected to be good sensitizers.