Spectral -Transient Electrothermal Modeling of Bifacial Perovskite Photovoltaic Modules

Bifacial perovskite photovoltaic modules are gaining traction in emerging applications such as BIPV, agrivoltaics, and lightweight portable systems, owing to their high efficiency, spectral tunability and low light performance. However, thermal instability under real-world conditions remains a barrier to long-term reliability. This work presents a spectral–transient electrothermal model that couples wavelength-resolved irradiance with dynamic heat generation and multilayer thermal conduction across seven functional layers: front glass, FTO, TiO₂, perovskite, Spiro-OMeTAD, EVA, and rear glass. The model incorporates nonlinear radiative losses and convective cooling, with transient temperature profiles solved using stiff ODE solvers. Under nominal operating conditions, the perovskite layer reaches 64.5 °C, with TiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">₂</inf> and Spiro at 63.7 °C and 63.5 °C, and outer layers cooling to 51.2 °C (EVA) and 49.8 °C (rear glass). At albedo = 0.3 and bifaciality = 0.8, bifacial modules dissipate ~29% more heat than monofacial ones (837 W/m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> vs. 648.8 W/m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>), despite higher power output. The thermal time constant is shorter for bifacial modules (~300 s) compared to monofacial (~360 s), indicating faster heating and lower thermal inertia. Heatmaps over the bifaciality– albedo space (0–1.0) identify thermal crossover regimes. This model supports predictive thermal analysis and design optimization of perovskite PV systems.