Boosting spectral response of multi-crystalline Si solar cells with Mn2+ doped CsPbCl3 quantum dots downconverter

Abstract

Conventional multi-crystalline Si solar cells present limited spectral response in the near ultraviolet region due to the parasitic absorption caused by passivation layer and heavily doped emitter layer. Converting ultraviolet light into visible light is a promising way to improve the performance of the devices. Herein, CsPbCl3: Mn2+ quantum dots are applied onto the front of the multi-crystalline Si solar cells as the luminescent downconverter to improve light harvesting in the short wavelength region. CsPbCl3: Mn2+ quantum dots with large Stokes shift (>1000 meV) and high quantum yield (62%) effectively convert the normally low responding spectral in the ultraviolet region into usable visible light at ∼600 nm for improving photoelectric conversion efficiency of the devices. Combining with the unique light-trapping architecture of multi-crystalline Si solar cells, external quantum efficiency in the ultraviolet region is evidently improved, leading to an increased conversion efficiency of 6.2%. Meanwhile, solar cells coated with CsPbCl3: Mn2+ quantum dots luminescent downconverter layer also exhibit favorable photostability under AM 1.5G illumination and reproducibility. Based on these characteristics, we deem this light-management strategy could be applied on mass product multi-crystalline Si solar cells, and easily extended to enhance the performance of other solar cells.