Colloidal Quantum Shells: An Emerging 2D Semiconductor for Energy Applications

Low-dimensional semiconductors hold strong promise for future energy applications. These nanomaterials are inexpensive to process and offer a broad spectrum of attractive quantum-mechanical properties. The notorious problem of low-dimensional nanostructures, however, lies in their limited performance under high energetic loads when more than one exciton per particle is created. Multiple excitons undergo fast annihilation, causing efficient roll-off in energy-intensive applications, including high-brightness light-emitting diodes, X-ray scintillators, and solar cells. In this Focus Review, we highlight an emerging type of low-dimensional semiconductors that make it possible to avoid such multiexciton (MX) energy losses. Recently demonstrated colloidal quantum shells benefit from the spatial separation of multiple excitons, which leads to extraordinary improvements to MX lifetimes and MX quantum yield. This makes the quantum shell morphology attractive for solution-processed optical and electrical devices. Here, we compare the optoelectronic properties of quantum shells against other low-dimensional semiconductors and discuss their emerging opportunities in solid-state lighting and energy-harvesting applications.