A sustainable future for photonic colloidal nanocrystals

Abstract

Colloidal nanocrystals – produced in a growing variety of shapes, sizes and compositions – are rapidly developing into a new generation of photonic materials, spanning light emitting as well as energy harvesting applications. Precise tailoring of their optoelectronic properties enables them to satisfy disparate application specific requirements. However, the presence of toxic heavy metals such as cadmium and lead in some of the most mature nanocrystals is a serious drawback which may ultimately preclude their use in consumer applications. Although the pursuit of non-toxic alternatives has occurred in parallel to the well-developed Cd- and Pb-based nanocrystals, synthetic challenges have, until recently, curbed progress. In this review, we highlight recent advances in the development of heavy-metal-free nanocrystals within the context of specific photonic applications. We also describe strategies to transfer some of the advantageous nanocrystal features such as shape control to non-toxic materials. Finally, we present recent developments that have the potential to make substantial impacts on the quest to attain a balance between performance and sustainability in photonics.