Impact of π‐Bridged Thiophene‐Based Materials on Hole Transport in Perovskite Solar Cells and Donor Functionality in Organic Solar Cells: A Computational Study

The design of hole‐transporting materials (HTMs) for solar cells via molecular engineering is presented in this work. The HTMs (Z26‐1 to Z26‐4) are designed around a thiophene core with electron‐withdrawing groups, triphenylamine side arms, and bridge groups, following the D–π–A–π–D configuration, in place of the reference Z26‐R, which contains a variety of thiophene derivatives at the core as acceptors. Quantum computations are used to investigate correlations between structure and properties of the designed HTMs, taking into account solubility‐related descriptors, optoelectronic, and electrochemical properties. Favorable band alignment with perovskite layers and promising predicted photophysical properties, such as favorable hole‐transport‐related parameters and effective charge transfer, are displayed by the proposed HTMs. Z26‐1 to Z26‐4 exhibit deeper HOMO energy levels (ranging from −4.61 to −4.86 eV), smaller bandgaps (2.54–2.65 eV), optical transparency (539–563 nm), and decreased RE (0.178–0.258 eV), suggesting a potentially favorable hole‐transporting character, which may be associated with enhanced hole delocalization facilitated by the thiophene core. The results elucidate the structure−property relationships governing charge transport in thiophene‐based HTMs, demonstrate their ability to function as active layers in organic solar cells, and highlight the role of molecular engineering in optimizing their optoelectronic properties for photovoltaic applications.