UC Berkeley

Advances in colloidal nanocrystal chemistries have enabled more complex fabrication of nanostructured materials. Colloidal nanocrystals can be easily deposited from solution and used in a variety of optoelectronic applications such as photodetectors and photovoltaics. Colloidal nanocrystals deposited as films act as the light absorbing layer. These films can be used as-is or be sintered into polycrystalline films. Introducing dopant species as a surface species on semiconducting nanocrystals allows controlled doping profiles in sintered films where the dopant preferentially segregates at the grain boundaries. Chloride in CdTe films is one well-known example of this phenomena. The focus of this work is designing chloride-capped CdTe nanocrystal building blocks and sintering these into polycrystalline films with controlled grain structure and therefore doping profiles. Applications investigated for these films are solar cells and photodetectors.