Pushing the Efficiency Envelope for Semiconductor Nanocrystal-Based Electroluminescence Devices Using Anisotropic Nanocrystals

Colloidal semiconductor nanocrystals hold great promise in display technologies, as the tunable energy levels and narrow emission bandwidth allow for wide gamut in color space. Impetus for energy-efficient, high-color-quality display has driven the surge of interest in electrically driven quantum dot-based light-emitting diodes (QD-LEDs). While extensive efforts have led to synthesis of QDs with near-unity photoluminescence quantum yield and fabrication of QD-LEDs with external quantum efficiency reaching to the theoretical limit (∼20%), low out-coupling factor poses a challenge in the way of improving the device performance when spherical QDs are used. Geometrically anisotropic nanocrystals (NCs) such as nanorods or nanoplatelets represent a unique possible solution to enhancing light extraction efficiency. In this Perspective, we highlight important design principles of individual anisotropic NCs and their assembly in the context of LED applications.