Advancing perovskite solar cell performance: Enhanced efficiency and stability through superimposed PbS QDs

Abstract

This study investigates enhancing efficiency in thin-film photovoltaic devices by incorporating varying-sized superimposed PbS colloidal quantum dots (CQDs). These CQDs offer tunable near-infrared absorption, multiple exciton generation effects, and solution processability, rendering them promising for improved performance. Superimposing QDs of different sizes extends the device's absorption spectrum beyond conventional limits, utilizing tailored absorption coefficients for broader sunlight wavelength utilization and increased solar energy conversion efficiency. Each QD group exhibits a unique absorption coefficient, with a peak at its central wavelength from the Schrödinger equation solution. Spectral analysis reveals strategic enhancement in light absorption across visible and near-infrared regions, broadening the perovskite absorption range beyond 800 nm. These QDs enhance both infrared and visible spectra, improving light harvesting. Summing the absorption of single QD groups creates a continuous spectrum, enhancing perovskite film stability and morphology. Rigorous optical analysis and comprehensive electrical modeling investigate charge carrier interactions within the photovoltaic framework. The study verifies around 24 % efficacy enhancement compared to QD-absent configurations, surpassing uniformly dispersed QDs by 11 %. Optical and electrical analyses yield a short-circuit current of 26.7 mA/cm2, open-circuit voltage of 1.13 V, fill factor of 0.88, and overall efficiency of 25.12 % in superimposed configurations. Results underscore the significance of varied QD dimensions and layered structures for enhanced absorption, offering a promising route for advancing thin-film solar technology. The study showcases the potential of PbS CQDs with varying radii in photovoltaics, contributing to improved efficiency and stability, with implications for the future of solar energy technology.