Intrinsic characteristics of Si solar cells coated with thick luminescence down-shifting sol–gel glass films

Abstract

AbstractWe investigate the effects of several-hundred-micron thick luminescence down-shifting (LDS) films composed of sol–gel glass with Zn-based nanoparticles (NPs) dispersed on the characteristics of Si solar cells. Their internal quantum efficiencies (IQEs) are successfully measured by separating the contributions of downshifted photons in measuring reflectance for 300–400 nm, wavelengths of incident photons absorbed by the NPs. We find that IQEs for this wavelength range are more enhanced by employing thicker LDS films, i.e. LDS films with higher optical densities. We also discuss the relationship between the number density of NPs in LDS films, their optical properties, and the IQEs of cells. We observe a discrepancy between the measured and calculated IQEs and note that this is the result of downshifted photons escaping across the sides of the LDS films.