Terahertz Field-Induced Reemergence of Quenched Photoluminescence in Quantum Dots

TL;DR

This paper demonstrates that high-field terahertz pulses can rebrighten quenched quantum dots by removing excess charges, significantly improving photoluminescence and offering new control methods for luminescent devices.

Contribution

It introduces a novel use of terahertz pulses to recover photoluminescence in quantum dots by charge removal, a method not previously explored.

Findings

Terahertz pulses can brighten quenched quantum dots on metallic surfaces.

The effect persists for minutes after THz irradiation.

THz fields reduce non-radiative recombination by removing excess charges.

Abstract

Continuous and concerted development of colloidal quantum-dot light-emitting diodes over the past two decades has established them as a bedrock technology for the next generation of displays. However, a fundamental issue that limits the performance of these devices is the quenching of photoluminescence due to excess charges from conductive charge transport layers. Although device designs have leveraged various workarounds, doing so often comes at the cost of limiting efficient charge injection. Here we demonstrate that high-field terahertz (THz) pulses can dramatically brighten quenched QDs on metallic surfaces, an effect which persists for minutes after THz irradiation. This phenomenon is attributed to the ability of the THz field to remove excess charges, thereby reducing trion and non-radiative Auger recombination. Our findings show that THz technologies can be used to suppress and control such undesired non-radiative decay, potentially in a variety of luminescent materials for future device applications.