Flexible thin film solar cells on cellulose substrates with improved light management

Cellulose substrates for PV applications present a fibrous surface texture that is not suitable for the uniform deposition of thin-film solar cells causing poor device performance. However, uniform thin-film deposition and efficient light management for solar cells can be achieved on cellulose substrates by transferring well-known surface textures that provide an adequate surface for thin film solar cell deposition and also, provide light scattering properties into the cellulose surface. In this work, we study the properties of crater-like textures transferred onto cellulose substrates by nanoimprint lithography and the corresponding effect on the J-V and EQE characteristics of amorphous silicon thin-film solar cells. The prototype solar cells are deposited on cellulose substrates and the results are compared with the results of such solar cells deposited on flat glass substrates. The results show that the J-V characteristics of solar cells deposited on planar as well as textured glass substrates are well reproduced. Due to the process routine, the solar cells on the cellulose substrate with nanoimprinted textures show an increase in the short circuit current density and power conversion efficiency over previous results in our laboratory.