Charge Injection, Charge Trapping and Charge Transfer in Quantum-Dot Solids

This study reports on fundamental processes in Quantum-Dot Solids, after light absorption. Transient Absorption and Time-resolved Photoluminescence spectrocopy reveal the dynamics of charge transfer and charge trapping processes. Typically, both occur on a picosecond time scale and compete with each other. We find that the efficiency of these processes depends on the Fermi level in the Quantum-Dot Solid. The latter can be controlled electrochemically, via charge injection into the Quantum-Dot Solid, using a potentiostat. The presented findings aid the rational design of opto-electronic devices based on Quantum Dots, such as solar cells or LEDs.