Physics-Informed Surrogate Modeling and Sensitivity Analysis of h-BN Interfacial Enhancement in Thin-Film Photovoltaics

The manuscript investigates whether a two-dimensional hexagonal boron nitride (h-BN) interfacial layer can enhance the performance of five thin-film photovoltaic absorbers—CdTe, GaAs, GaSb, InSb, and InGaN—and, more importantly, how reliable the model used to predict that enhancement actually is. The physical premise is straightforward. Thin-film solar cells such as CdTe and CIGS suffer from an open-circuit voltage deficit caused by interfacial recombination at the back contact. h-BN, with its wide bandgap (6.0 eV), chemical stability, and van der Waals nature, has been proposed as an electron reflector that blocks minority electrons from reaching the back contact while still permitting hole extraction. Mumtaz et al. (2026) demonstrated a 68% relative efficiency enhancement for CdTe–h-BN devices. The natural next question is which other semiconductor–h-BN pairings might benefit similarly. Answering that question requires a model, and the model requires a parameter—the interface quality factor fmatfmat—that has been measured only for CdTe