Optimization of ZnO down-shifting photoluminescent quantum dots thin film layers and their influence on single-crystal silicon solar cells

In the present work, the synthesis and characterization of photoluminescent ZnO quantum dots (QDs) and their effect in the performance of in-house-fabricated single crystal silicon solar cells is detailed. The down-shifting effects of the colloidal quantum dots were characterized by collecting and analyzing their absorption and photoluminescence spectra. Additionally, the crystallographic analysis was performed employing X-ray diffraction (XRD). Results from previous reports employing pH 10 and pH 12 values during synthesis indicate average power conversion efficiency (PCE) improvements as high as 14.14 % when utilizing pH 12 ZnO + PMMA films [1]. Given the promising improvements achieved with pH 12 ZnO QDs, optimization of the ZnO/PMMA layers was performed. The performance parameters of the fabricated solar cells before and after the application of the ZnO QDs layers was evaluated by current density-voltage (J-V) curves and external quantum efficiency (EQE) characterization, resulting on average PCE improvements up to 19.22%.