Cs-Symmetric Triphenylamine-LinkedBisthiazole-Based Metal-Free Donor–Acceptor Organic Dye for Efficient ZnO Nanoparticles-BasedDye-Sensitized Solar Cells: Synthesis Theoretical Studies and PhotovoltaicProperties

摘要

Herein, we have designed a metal-free donor–acceptor dye by incorporating an electron deficient bisthiazole moiety as a linker in between the electron donor triphenylamine and cyanoacetic acid acceptor. The bisthiazole-based organic dye >D1 was synthesized using the Pd-catalyzed Suzuki cross-coupling and Knoevenagel condensation reactions. On the basis of the optical, electrochemical, and computational studies, dye >D1 showed a better electronic interaction between the donor and acceptor moieties. As-synthesized C2 symmetric triphenylamine-linked bisthiazole-based organic dye >D1 has four anchoring groups, which play a significant role for better adsorption on the ZnO surface along with the enhanced kinetics of photoexcited electron injection. Consequently, photovoltaic properties of the organic dye >D1 has been carried out by fabricating the ZnO nanoparticles (ZnO NPs)-based solar device. We obtained the maximum incident photon-to-current conversion efficiency of about 56.20%, with a short-circuit photocurrent density (Jsc) of 13.60 mA cm^–2, which results in a power conversion efficiency (PCE) of 4.94% under AM 1.5irradiation (100 mW cm^–2). The high PCE value isthe result of proficient electron injection from ELUMO of dye >D1 to the conduction band ofZnO NPs, as suggested by the computational calculations. Electrochemicalimpedance spectroscopy measurement is carried out to calculate theelectron lifetime and also reveals the insight to the reduced chargerecombinations at the various active interfaces of the photovoltaicdevice.