18 December 2013 Novel Doping Scheme for Colloidal Quantum Dots

Schematic of normal and inverted PbS Quantum dot homojunction solar cell structures

Researchers at ICFO develop colloidal quantum dot homojunctions via cation substitutional doping. Researchers in the group led by Prof. Gerasimos Konstantatos report in a recent article in Nature Communication a novel doping scheme for colloidal quantum dots that enables the development of colloidal quantum dot homojunction solar cells. Doping in colloidal quantum dots has remained a grand challenge for many years. Recent efforts have demonstrated the effect of doping in the optical properties of quantum dots, however robust electronic-active doping has remained elusive.

In this work, the authors demonstrated that the doping character of colloidal quantum dots can be controlled by introducing heterovalent dopant cation atoms to transform a p-type semiconductor into an n-type semiconductor. The researchers have then showed that this can be utilized in robust solar cell structures operating under ambient conditions with respectable efficiencies.