Electrical Doping of Colloidal Semiconductor Nanocrystals—Electron-Only-Device & Hole-Only-Device

Auger recombination, whereby exciton recombination energy is transferred to a third carrier instead converted to a photon, in colloidal semiconductor quantum dots (QDs) have complicated to accomplish high-performance optoelectrical applications. For analyzing dynamics of QDs inside applications, previous studies have primarily focused on bi-exciton states and negatively charged exciton states, whereas positively charged exciton states are hardly investigated due to difficulties in adding and stabilizing extra holes in QDs.<br/>Herein, we demonstrate electronic systems, electron-only-device (EOD) and hole-only-device (HOD), injecting extra carriers to QDs and analyze auger lifetime spectroscopy in chorus with electrical characteristics. This method adds extra carriers to CdSe/CdS heterostructured QDs whose multi-carrier states are well studied for long time, so exhibits the key spectroscopic signatures including development of fast decay, 1S bleach, auger quenching of photoluminescence (PL), and PL spectra shift. We assign dynamics to three distinct states of different lifetimes attributed to single exciton, energy transfer to metal, and charged exciton respectively, and the expected PL intensities from the lifetime accord precisely with measured PL intensities. Additionally, these spectroscopic and electronic changes are recovered totally, just discharged without any bias. Out method offers a universal tool of creating multicarrier states of QDs in a non-destructive manner and opens a new prospect in analyzing positively charged trion in veil before.