Enhanced structural and optoelectronics performance of perovskite solar cells via MnSe2 incorporation in a MAPbI3 absorber layer

Abstract

This study presents a novel approach for enhancing the efficiency of perovskite solar cells (PSCs) by incorporating MnSe₂ into a MAPbI₃ absorber layer. UV-visible (UV-vis) spectroscopy revealed a redshift in the absorption edge, reducing the bandgap from 1.71 eV to 1.62 eV, indicating improved light absorption. The refractive index increased from 2.84 to 2.89, while the extinction coefficient increased from 2.215 to 2.222, ensuring minimal non-radiative losses. Photoluminescence (PL) spectroscopy exhibited an enhanced emission peak, suggesting reduced non-radiative recombination. X-ray diffraction (XRD) analysis showed an increased crystallite size from 25.4 nm to 34.1 nm, with a decrease in dislocation line density (DLD) from 1.55 × 10¹⁵ to 0.86 × 10¹⁵, indicating improved crystallinity. Electrochemical impedance spectroscopy (EIS) revealed an increase in recombination resistance (R_rec) from 4835 Ω to 5941 Ω, confirming reduced charge recombination. Current density–voltage (J–V) measurements demonstrated an increase in power conversion efficiency (PCE) from 18.09% (MAPbI₃) to 21.95% (MnSe₂–MAPbI₃), attributed to enhanced charge transport and energy band modification. External quantum efficiency (EQE) measurements further validated the improved light-harvesting capability of MnSe₂–MAPbI₃. These findings highlight MnSe₂ as a promising additive for high-performance PSCs, offering improved optical, structural, and photovoltaic properties. Future research can explore stability enhancement for long-term device performance.