Understanding the role of the density of traps in quantum dots integrated into light-emitting devices

Abstract

Quantum-dot (QD) based light-emitting devices under the presence of electronic trap states present at the surface states of QDs have been studied. The efficiency of optoelectronic devices is curtailed due to non-radiative recombination arising due to trap-states which opens a pathway for trapping of charge carriers and presence of free charge carriers which leads to Auger recombination. Theoretical analysis of the effect of the electronic trap states has been done where QDs without any trap state and QDs with few active trap states have been considered. The effect of no. of traps states active on the switching rates and photoluminescence (PL) intensity has also been studied. The results obtained show strong dependence of switching rates on the configuration of trap states and enhanced trapping rate when higher number of trap states are active. The PL intensity also reduces for higher number of active trap states as compared to QD with no trap state.