Thienothiophene and dithienothiophene derivative P-type organic semiconductors for perovskite solar cells

Abstract

Organic compounds have gained significant attention due to their tunable physical and chemical properties, making them highly suitable for electrical and optoelectronic applications. Among these, thiophene-based derivatives, such as thienothiophenes (TT) and dithienothiophenes (DTT), exhibit excellent conjugation, stability, and conductivity, making them ideal candidates for organic material research. Organic semiconductors, characterized by their excitonic charge transport, offer advantages over traditional inorganic materials, including flexibility, lightweight properties, and cost efficiency. This study focuses on the synthesis of thienothiophene-based materials for application in perovskite solar cells. The synthesized molecules employ a donor-π-donor (D-π-D) framework, incorporating TT and DTT as π-bridges and electron-rich donor groups such as EDOT, thiophene, and methoxy-substituted triphenylamine (TPA(OMe)₂). Five distinct molecules—TT-Ph(EDOT-TPA(OMe)₂)₃, DTT-Ph(Th-TPA(OMe)₂)₄, DTT-Ph-(EDOT-TPA(OMe)₂)₄, TT-PhOMe-(EDOT-TPA(OMe)₂)₂, and DTT-PhOMe-(EDOT-TPA(OMe)₂)₂—were synthesized via lithiation, bromination, and cross-coupling reactions (Suzuki and Stille couplings). Their structures were confirmed using 1H-NMR spectroscopy. The optoelectronic properties of these materials were analyzed through fluorescence, UV-Vis spectroscopy, and cyclic voltammetry, with the goal of optimizing their performance in perovskite solar cells. The findings of this research contribute to the development of high-performance organic semiconductors for next-generation photovoltaic applications.