Exciton Recycling in Triplet Energy Transfer from a Defect-Rich Quantum Dot to an Organic Molecule

Abstract

Surface defects are pervasive in quantum dots (QDs) and are detrimental to their applications. The recycling of trapped excitons is key for the efficient utilization of QDs, while the strategy for this is limited. Here, we discovered a unique recycling process for deep trapped excitons in molecule-coordinated defect-rich QD systems. Triplet–triplet energy transfer (TTET) from defect-rich QDs to surface-attached perylene-3-carboxylic acid (Pe) was investigated at a low temperature (77 K), and the contribution of defect state was suggested the Auger-assisted recycling process of the defect-trapped carriers, having insufficient energy for TTET. The discovery of TTET via exciton recycling from defects provides a new way to reuse untapped excitons in QDs and QD devices.