Somayyeh Alidoust | Searcharxiv

arXiv2026

Composition and Surface Termination Control Band Alignments in P3HT/Perovskite Heterostructures

Hybrid organic-inorganic perovskite heterostructures are emerging platforms for energy conversion and optoelectronic devices, yet the effects of composition and surface terminations on band alignment remain poorly understood. Here, using high-throughput first-principles calculations, we systematically reveal the effect of composition and surface termination on the band alignment of 820 heterostructures formed between poly(3-hexylthiophene) (P3HT) variants and conventional and mixed-cation metal halide perovskites. Band edge analysis predicts concentration dependent band alignments, with most Pb and Sn based perovskites exhibiting Type II and III behavior while mixed-cation CsMASnBr3 uniquely forms Type-I junctions with all P3HT variants. Explicit interface calculations reveal that surface termination can reverse the predicted alignment in conventional tin perovskites, while the mixed cation perovskite preserves Type-I alignment with P3HT regardless of termination. Despite negligible charge transfer, termination dependent band offsets produce markedly different carrier confinement, establishing design principles for engineering P3HT/perovskite interfaces.

cond-mat.mtrl-sci↗

arXiv2025

Interface Modeling of Perovskite Polymer Heterostructures for Enhanced Charge Transfer Efficiency in Hybrid Photovoltaic Materials

Perovskite solar cells (PSCs) based on methylammonium lead iodide (MAPbI3) exhibit remarkable photovoltaic performance, where interface engineering with hole transport layers (HTLs) is crucial for optimizing charge transfer and device efficiency. In this work, we present a density functional theory (DFT) study of the MAPbI3/poly(3-hexylthiophene) (P3HT) hybrid interface, focusing on the role of perovskite surface termination in determining interfacial stability and electronic structure. We model MAI- and PbI-terminated MAPbI3 surfaces interfaced with P3HT and compare their interfacial electronic properties. Electronic structure calculations reveal distinct differences in orbital hybridization and band alignment: the MAI/m-P3HT interface exhibits weak coupling, whereas the PbI/m-P3HT interface shows stronger hybridization and enhanced charge transfer. Band alignment confirms type-II, hole-selective character in both cases, with more pronounced valence band maximum adjustment for PbI. Charge difference maps, Bader analysis, and local density of states consistently indicate higher charge transfer and stronger electronic coupling for PbI termination. Electrostatic potential offsets and transport parameters further highlight termination-dependent differences, with lighter effective masses at PbI/m-P3HT and higher hole velocity at MAI/m-P3HT. These findings provide theoretical insight into interfacial charge transport mechanisms and offer guidelines for optimizing perovskite-organic hybrid solar cells.

cond-mat.mtrl-sci↗