Optimization Schemes for Efficient Multiple Exciton Generation and   Extraction in Colloidal Quantum Dots
  Multiple exciton generation is a process in which more than one electron hole pair is generated per absorbed photon. It allows us to increase the efficiency of solar energy harvesting. Experimental studies have shown the multiple exciton generation yield of 1.2 in isolated colloidal quantum dots. However real photoelectric devices require the extraction of electron hole pairs to electric contacts. We provide a systematic study of the corresponding quantum coherent processes including extraction and injection and show that a proper design of extraction and injection rates enhances the yield significantly up to values around 1.6. 
Fikeraddis A. Damtie, Khadga J. Karki, T\~onu Pullerits, and Andreas   Wacker
cond-mat.mes-hall