Long-lived and Well-resolved Mn2+ Ion Emissions in CuInS-ZnS Quantum Dots

CuInS2 (CIS) quantum dots (QDs) have tunable photoluminescence (PL) behaviors in the visible and near infrared spectral range with markedly lower toxicity than the cadmium-based counterparts, making them very promising applications in light emitting and solar harvesting. However, there still remain material- and fabrication- related obstacles in realizing the high-performance CIS-based QDs with well-resolved Mn(2+) d-d emission, long emission lifetimes as well as high efficiencies. Here, we demonstrate the growth of high-quality Mn(2+)-doped CuInS-ZnS (CIS-ZnS) QDs based on a multi-step hot-injection strategy. The resultant QDs exhibit a well-resolved Mn(2+) d-d emission with a high PL quantum yield (QY) up to 66% and an extremely long excited state lifetime up to ~3.78 ms, which is nearly two times longer than the longest one of "green" QDs ever reported. It is promising that the synthesized Mn(2+)-doped CIS-ZnS QDs might open new doors for their practical applications in bioimaging and opto/electronic devices.