CsCu2I3 Nanocrystals: Growth and Structural Evolution for Tunable Light Emission

CsCu 2 I 3 mixed with Cs 3 Cu 2 I 5 has shown potential applications as white-light-emitting materials, while their growth, structural evolution behaviors, and their impact on photoluminescence of CsCu 2 I 3 nanocrystals (NCs) are still not known. In this work, we investigated the growth and structural evolution of CsCu 2 I 3 nanocrystals with increasing reaction temperature. At low temperature and in the presence of a high dosage of oleic acid and oleylamine, Cs 3 Cu 2 I 5 nanoparticles, rather than CsCu 2 I 3 NCs, preferred to form in the hot-injection reaction system. Increasing the reaction temperature promoted the formation of CsCu 2 I 3 nanorods. Phase-pure CsCu 2 I 3 nanorods were steadily obtained at 180 °C. Structural evolution from less copper-containing NCs to copper-rich ones in the low-temperature reaction condition is highly related to the coordination of copper ions with OAm. More importantly, accompanying the growth of nanorods and structural evolution from Cu 3 Cs 2 I 5 to CsCu 2 I 3 , the color of photoluminescence emission of NCs changed from blue to nearly white and to yellow, but their photoluminescence quantum yield decreased from 36.00 to 9.86%. The finding in this work would give a view to the structural evolution of copper-containing perovskite-like halides, being helpful for adjusting their photoluminescence in white LEDs.