Carriers multiplication in neighboring surfactant-free silicon nanocrystals produced by 3D-surface engineering in liquid medium.

Abstract

Carriers multiplication in silicon nanocrystals (Si-ncs) in a one promising eefect to considerably enhance conversion efficiency of solar cells that can overcome theoretical limits. A close proximity of Si-ncs is an essential factor for carrier multiplication due to the separated quantum cutting effect. In this study we present results on investigation of 3-dimensional (3D) surface engineering of Si-ncs directly in water. Thus at the same time allow close proximity Si-ncs without of using any surfactant. The approach is based on ns laser treatment of Si-ncs dispersed in liquid solution. We explore the excitation wavelength dependence of photoluminescence quantum yield (ratio of the number of emitted and absorbed photons) for Si-ncs as prepared and surface engineered by ns laser processing. Our results suggest that close proximity of Si-ncs in spherical particles induced by laser processing might enhance also carriers multiplication.