Application of a Silicon Nanocrystal Down-shifter to a c-Si Solar Cell

Abstract

Silicon nanocrystals (Si NCs) in a matrix of SiO2 were applied to the front of a p-type c-Si solar cell as down-shifter. The down-shifting action of the Si NCs was confirmed from the analysis of spectral response measurements with the help of ray tracing simulations. Ray tracing simulations were performed to simulate the application of a Si NC layer with varying emission quantum efficiencies to the glass coversheet in a solar module with EVA as encapsulant. It is found that gain in Jsc is only achieved for a Si NC layer with high emission quantum efficiencies, which requires efficient quantum cutting. The most important loss factors identified are the low Si NC emission coupling efficiency in combination with parasitic absorption in the spectral range of high solar cell internal quantum efficiency.