Understanding and Overcoming Limitations in Perovskite Quantum Dots for High-Performance Light-Emitting Devices

Light-Emitting Diodes (LEDs) are semiconductor materials that emit light when current passes through them. The discovery of LEDs in 1962 has revolutionized modern optoelectronics. These LEDs have evolved from the early GaAsP-based red emitters to more efficient GaN-based devices, and the latest development is LEDs incorporating perovskite quantum dots.

Perovskite quantum dots show high PLQY, narrow emission linewidth, fast radiative recombination, and color tunability due to the quantum confinement effect. Even with all these properties, these materials show several limitations, like Auger recombination, Ostwald ripening, surface trap formation, and the instability of the devices under high voltage, heat, and moisture.

This seminar focuses on the recent developments to improve the performance and stability of perovskite quantum dot-based devices. A quantum dot in matrix method demonstrates defect suppression and charge balance, achieving luminance value exceeding 4700cd/m² with an operational half-life of 2100hrs. Surface passivation using guanidinium iodide has extended the exciton lifetime, and the external quantum efficiency (EQE) increased 2-fold. Furthermore, molecular ripening control with pyridinyl-containing ligand PZPY limits Ostwald ripening and reinforces Pb-N coordination at the surface, leading to enhanced spectral stability and high EQE value. All these recent advancements in structural stabilization have improved their efficiency and operational stability.