Synthesis of dual-emission Ag- and Mn-codoped Zn-In-S nanocrystals and their optical radiometric temperature sensors

In this work, a facile approach to synthesize the Ag- and Mn-codoped Zn-In-S nanocrystals (NCs) with dual emissions as ratiometric temperature sensors is reported. The as-synthesized codoped Zn-In-S NCs have a uniform size distribution and exhibit a zinc blende ZnS phase structure. Moreover, the as-produced codoped NCs show dual emission peaks which center at green and orange-red regions and have a photoluminescence quantum yield (PL QY) up to 45%. The time-resolved PL spectroscopy and X-ray photoelectron spectroscopy characterizations reveal that the dual emissions of these NCs are derived from the intrinsic emission of Ag + and Mn 2+ , respectively. Moreover, the relative intensity ratio of dual emissions can be tailored by adjusting the Ag and Mn doping concentrations. The as-built ratiometric temperature sensors based on the codoped NCs exhibit a thermometric sensitivity of ~ 0.17% K -1 over a broad window of 80–200 K, suggesting that these codoped Zn-In-S NCs are promisingly used for bio-optical ratiometric temperature sensing.