In-situ neodymium ion doping into perovskite nanocrystals over ex-situ and its importance in triclosan sensing

Abstract

All inorganic cesium lead halide (CsPbX3, X = Cl, Br or I) perovskite nanocrystals (NCs) exhibit wide absorption range and narrow bandwidth emission. However, the presence of defects leads to lack of long term stability and reduced photoluminescence quantum yield (PLQY). Herein, we have studied the effect of in-situ and ex-situ doping of Nd3+ into CsPbBr3 matrix to understand the importance of technique of doping and its influence on perovskite properties. It was found that optimum concentration (6%) of in-situ doping of Nd3+ into CsPbBr3 enhances PLQY by 20% and lifetime by 23 ns, whereas ex-situ Nd3+ doping shows quenching of PL. Dopant precursor was carefully chosen to avoid any anion exchange/addition unlike in previously reported studies. The exceptional quantum yields of in-situ doped Nd-CsPbBr3 NCs with narrow full width half maximum allows intense fluorescence emission and the enhanced PL helped us to utilize this as highly sensitive probe for rapid detection of a model pollutant triclosan. The enhancement in PL through in-situ doping enhances the detection levels by one order of magnitude to achieve up to nM concentration. The triclosan sensing mechanism is proved to be dynamic quenching substantiated by temperature dependent PL and lifetime decay study. This work provides insights into use of appropriate doping techniques to attain enhanced and controlled properties, through which we could reach higher detection limits in such perovskite sensing systems.