First-Principles Investigation of Perovskite Solar Cell Efficiency Limits and Stability Under Nigerian Tropical Irradiance and Humidity Conditions

This research conducts a first-principles investigation of the power conversion efficiency limits and operational stability of perovskite solar cells under the specific high-irradiance, high-humidity, and high-temperature conditions characterising Nigerian tropical deployment environments, providing original theoretical and experimental contributions to the photovoltaics science required to enable perovskite technology adoption in Nigerian and sub-Saharan African solar programmes. Perovskite solar cells have achieved laboratory efficiencies exceeding 26 percent but face significant stability challenges under moisture, heat, and high UV flux that are particularly acute in Nigeria's tropical climate and currently prevent their commercial deployment in Nigerian solar installations. The theoretical contribution originates from density functional theory calculations of perovskite crystal structure stability under the combined thermal and humidity stress conditions typical of Lagos and Kano climates, revealing the atomistic degradation pathways that initiate halide segregation and phase decomposition under tropical conditions and identifying the interfacial passivation chemistry modifications that can interrupt these pathways. The experimental programme fabricates a series of perovskite cell architectures with systematic variations in passivation layer composition and encapsulation design, subjecting them to accelerated tropical ageing protocols developed from measured Nigerian environmental data. Original efficiency limit analysis using detailed balance calculations incorporating the measured Nigerian solar spectrum and realistic operating temperatures quantifies the theoretically achievable efficiency advantage of perovskite over silicon in Nigerian conditions. The research identifies two perovskite compositions and one encapsulation architecture as viable for Nigerian deployment based on demonstrated stability performance. Keywords: perovskite solar cell, efficiency limits, tropical stability, Nigeria, first-principles.