Carrier selection in downshifting perovskite quantum dot films for crystalline silicon solar cells

Crystal silicon solar cells have long dominated the photovoltaic market, but their photoelectric conversion efficiencies are difficult to further improve. Although some studies have proposed to coat perovskite quantum dot downshifting film on surface of the device, there remains a lack of systematic research on the interaction between the quantum dots and their carriers. We selected three typical polymers in optical film, ethylene-vinyl acetate copolymer (EVA), polymethyl methacrylate copolymer (PMMA) and ethylene-methyl methacrylate copolymer (EMMA), and mixed them with perovskite quantum dots solutions to prepare composite films. Through component analysis, optical characterization, and theoretical calculations, we systematically explored the interaction between different polymers and perovskite quantum dots. Under protection of three composite downshifting films based on EVA, PMMA, and EMMA, the efficiencies of crystal silicon cells were increased by 0.49 %, 0.21 % and 0.81 %, respectively. As demonstrated by density functional theory calculations, it is the strong interaction between polymer chains and perovskite quantum dots make EMMA become the champion carrier for perovskite quantum dot. This study presents a promising perovskite quantum dot/polymer composite film characterized by low production costs and stable performance, demonstrating significant potential in the field of photovoltaics.