Numerical simulation of thickness-dependent carrier collection efficiency in SnSe absorber layers

SnSe-based photovoltaic absorbers offer a standard for attaining exceptionally high-performance and comparatively cost-effective solar energy conversion across a wide thickness range. This work investigates a comprehensive numerical assessment of thickness dynamics affecting energy acquisition, carrier acquisition, and recombination mechanisms within SnSe photovoltaic absorbers. The model integrates spatial photogeneration, drift–diffusion transport, and trap-assisted recombination to quantify the interaction between absorption enhancement and carrier-extraction efficiency across the absorber layer. The analysis combines detailed recombination kinetics and foundational diode characteristics to substantial changes in [Formula: see text], [Formula: see text], and fill factor for diverse different film thicknesses. A thorough evaluation of inherent collection probability, fractional recombination fractions, and measured lifetime degradation allows the precise identification of an optimal absorber thickness range that ultimately maximizes conversion efficiency. These observations confirm that increased thickness significantly improves optical absorption but always introduces significant electrical penalties, invariably dictating the maximum achievable power conversion efficiency. Bandgap verification using crucial absorption-edge data verifies the essential direct-gap of the material and the complete thickness of independence of the main optical transition. Parametric extraction across specific thickness points consistently highlights noticeable nonlinear trends in [Formula: see text], [Formula: see text], FF, and ultimate efficiency, closely following complex transport and internal recombination mechanisms. The outcomes demonstrate that appropriate absorber thickness certainly plays a critical role in balancing crucial optical and essential electrical processes within robust SnSe photovoltaic structures. The comprehensive modeling framework provides valuable quantitative insight into perfectly optimizing SnSe absorber layers for premier high-performance thin-film solar-cell applications.