To nano or not to nano for bright halide perovskite emitters

The halide perovskite family has, arguably, become today’s most promising emerging materials sets for optoelectronic applications. Here, we discuss the underperformance to date of the colloidal nanocrystal forms of these materials when employed in electroluminescent lighting devices relative to their counterparts, in which the emitter layer is in the form of polycrystalline films. However, we highlight the bright future of halide perovskite colloidal nanocrystals in light-emission technologies such as LCD displays, quantum light sources and even alternative LED configurations, as well as key guidelines for their further development to get there.