Abstract
Perovskite solar cells (PSCs) are deemed to be the upcoming photovoltaic technology with a promise to surpass the silicon solar cell in near future. Herein, we propose a bandgap grading (of 1–3 eV under the effect of stoichiometry variation) profile to maximize the spectrum absorption for the perovskite absorber material, leading to efficiency reaching the Shockley-Queisser (SQ) limit. A comparative study of linear bandgap grading for the different absorber conduction band slope profiles has been analytically performed and analyzed. The bandgaps grading profiles were optimized for device performance, defect tolerances, and optical absorption (quantum efficiency). Accordingly, it has been observed that for optimal efficiency, a high range of bandgap grading is not essential, but rather a well-optimized small range of bandgap grading of 1.4–1.2 eV at the two ends of the absorber layer results in 31% power conversion efficiency.