Photo- and Electroluminescence from Zn-Doped InN Semiconductor Nanocrystals

There is a critical research need for efficient luminescent colloidal nanocrystals, free from cadmium and lead whose toxicity subjects them to usage restrictions, with applications from display devices to biology. Approaches to directly replace cadmium-based materials have mainly focused on indium phosphide-based nanocrystals, however these too are subject to concerns over toxicity. Few other alternatives have been found that can compete with the emission range and efficiency of Cd- and Pb-based nanocrystals. Group III-nitride nanocrystals, and their alloys, offer the exciting potential to tune bandgap energies from the ultraviolet to the near infrared yet a robust route toward efficient luminescent nitride nanocrystals is lacking. Here, the synthesis of photoluminescent indium zinc nitride quantum dots exhibiting tunable emission through the visible to near infrared spectra region, with quantum yields of up to 30% is reported. Capping the nanocrystals with both a GaN and ZnS shell significantly increases air stability and emission quantum yields. A proof-of-principle indium zinc nitride nanocrystal light emitting diode is also demonstrated. This work overcomes the significant challenges that have prevented the full exploration of nitride-based semiconductor nanocrystal development, providing a new system for further exploration as a heavy-metal free alternative to current state-of-the-art materials.