Zinc sulfide quantum dots coated with PVP: applications on commercial solar cells

摘要

In this study, we report the synthesis and characterization of zinc sulfide quantum dots (ZnS QDs) coated with different concentrations of polyvinylpyrrolidone (PVP), as well as their deployment as luminescent films on the window side of previously characterized commercial silicon solar cells to quantify their influence on the power conversion efficiency (PCE). The synthesis of the semiconductor nanoparticles was carried out by the reaction of zinc nitrate with sodium sulfide in an aqueous solution at room temperature. XRD measurements indicated a cubic sphalerite phase of the QDs crystal structure, which was not modified by the addition of PVP in the synthesis process. However, the PVP concentration was a key parameter to modulate the size distribution and the luminescent intensity of the QDs, suggesting that an increase in the PVP concentration produced a slight decrease in the QDs size and improved their luminescent properties desired for the photovoltaic applications. The obtained nanoparticles presented great absorption of photons with energies above 3.72 eV and a broad intense blue photoluminescent emission centered at around 450 nm, under excitation of ultraviolet light of 325 nm. The implementation of the synthesized ZnS QDs as spectral response enhancer produced improvements on the performance of solar cells, leading to increases of 0.7%, 1.9%, and 6.1% on the efficiencies of commercial polycrystalline solar cells after the deposition of ZnS QDs synthesized without PVP, with 0.05 mM PVP and with 0.10 mM PVP, respectively.