Experimental findings and SCAPS-1D simulations for high-efficiency MAPbI₃ perovskite solar cells beyond 31%

The sequence and texture of methylammonium lead triiodide (MAPbI₃) films, spin-coated by a one-step process, are analyzed using X-ray diffraction, atomic force microscopy, profilometry, and ultraviolet-visible spectroscopy to understand the film’s fundamental properties. The structural and optical results demonstrate the formation of the MAPbI₃ crystalline phase with a tetragonal crystal structure and a direct band gap of 1.53 eV, indicating its potential as an effective absorber of visible light. An n-i-p planar structure (ITO/SnO₂/MAPbI₃/Spiro-OMeTAD/Au) is then adopted for drift-diffusion SCAPS-1D simulations, considering realistic conditions such as resistance paths, reflection at the front contact (ITO), and various recombination mechanisms, including Shockley-Read-Hall (SRH), radiative, and Auger recombination. Based on optimal parameters and the investigation of novel alternative HTLs, back and front contacts, it is proposed that D-PBTTT-14, reduced graphene oxide (RGO), and Al-doped zinc oxide (AZO) could effectively replace traditional HTLs and electrodes such as Spiro-OMeTAD, Au, and ITO, respectively, thereby enhancing solar cell performance. The proposed solar cell structure (AZO/SnO₂/MAPbI₃/D-PBTTT-14/RGO) demonstrates an impressive efficiency of 28.39%.