Plasmon-enhanced colloidal silver telluride quantum dots for boosted near-infrared photodetection performance

Abstract

In the realm of imaging and optoelectronic devices, near-infrared (NIR) light has garnered significant attention due to its unique properties of deep tissue penetration and anti-interference capability. Among various NIR materials, silver telluride (Ag2Te) colloidal quantum dots (QDs) have emerged as promising candidates for their low toxicity and broad absorption/emission range. However, the photoluminescence quantum yield (PL QY) and photostability of Ag2Te QDs is relatively low, which poses a considerable challenge to their practical application. We herein report a novel strategy to enhance their optical properties by leveraging the localized surface plasmon resonance (LSPR) effect of non-noble metallic Cu2-xS1-ySey nanoparticles (NPs). Experimental results demonstrate that the core@shell@shell Cu2-xE@SiO2@Ag2Te (E=Se, S) nanostructures (NSs) exhibit a remarkable fluorescence enhancement factor of up to 2.72, with the PL QY increasing from 9.52% to 14.46% and the fluorescence lifetime being significantly prolonged with respect to those of bare Ag2Te QDs. Furthermore, the optimized NSs-based photodetectors show a 4.18-fold enhancement in responsivity compared to bare QD-based devices, highlighting the effectiveness of LSPR in optimizing carrier dynamics.