MXene-integrated Cs2AgBiBr6 perovskite solar absorber for ultrabroadband energy harvesting: Finite element modelling and machine learning optimization

Despite being eco-friendly alternatives to traditional lead-containing solar cells, the adoption of lead-free perovskite solar cells has been limited due to inadequate broadband light absorption, interfacial carrier recombination, and a dearth of systematic studies on the impact of interfacial materials and carrier transport on cell performance. To address the above problems, the current study recommends a design integrating the Cs 2 AgBiBr 6 perovskite solar absorber with MXene, using the optimal configuration FTO/Cd 0.5 Zn 0.5 S/MXene/Cs 2 AgBiBr 6 /NiO/Ag to enhance carrier transport and optical confinement. The solar absorber design offers an average absorption of more than 80% in the 0.3-3.3 μm wavelength band, and a maximum absorption of close to 99% due to the combined effects of local surface plasmon resonance, Fabry-Pérot cavity resonance, and impedance matching.The proposed solar cell design offers a short circuit current density of 26.96 mA cm −2 , and a power conversion efficiency of 22.84%. Moreover, a detailed comparative study reveals that Cd 0.5 Zn 0.5 S and NiO offer the optimal electron and hole transport balance among several ETL and HTL materials, whereas the proposed combination of Cs 2 AgBiBr 6 /MXene yields the best overall photovoltaic performance compared to other examined perovskites, despite each material exhibiting better values in specific photovoltaic properties. In addition, by comparing MXene and graphene, one can conclude that MXene is capable of improving broadband absorption, short-circuit current density, and power conversion efficiency and thus serves as a superior interfacial layer for the proposed configuration. Moreover, by using machine learning algorithms, namely, k-nearest neighbours, Random Forest, and Gradient Boosting, one can predict the optical behaviour of the proposed design, with the Random Forest algorithm demonstrating the best prediction accuracy and excellent conformity with finite element simulations. Overall, the proposed perovskite-based solar cell assisted by MXene shows high effectiveness in terms of solar energy harvesting.