Solar Cells with Inorganic Absorber Layers Made of Nanocrystals

Abstract

Colloidal semiconductor nanocrystals are not only interesting as materials for bulk heterojunction hybrid solar cells, where the inorganic nanocrystals are blended with conductive polymer to form the photoactive layer of the devices. Closer to established inorganic thin film solar cells, it is also possible to construct photovoltaic devices where the absorber layer consists of colloidally prepared nanoparticles only, i.e., without the additional presence of a conductive polymer. Thereby, the approach conserves the advantage that the photoactive layer can be produced from liquid media, so that potentially, cost-efficient technologies like printing can be applied also in this case. Mainly two types of solar cells with solution-producible absorber layers of colloidal nanocrystals have been developed, namely so-called Schottky solar cells and depleted heterojunction solar cells. This research field is still young, but has made rapid and impressive progress in just a few years. At present, the performance of corresponding solar cells even exceeds that of polymer/nanoparticle bulk heterojunction cells. The present chapter gives an introduction to the device concepts and reviews the current developments in the field.