Near-Unity Photoluminescence Quantum Yield and Highly Suppressed Blinking in a Toxic-Metal-Free Quantum Dot

• DOI: 10.1021/acs.jpclett.0c03519
• Publication Date: 2021-02-02T08:52:29Z
• Authors: Swarnali Ghosh; Saptarshi Mandal; Soumen Mukherjee; Chayan K. De; Tridib Samanta; Mrinal Mandal; Debjit Roy; Prasun K. Mandal
• Keywords: Pharmacology; ultrasensitive single-particle spec.; Biophysics; SPS; near-unity; 01 natural sciences; Mathematical Sciences not elsewhere classified; 0104 chemical sciences; ultrabright CAS QD; Astronomical and Space Sciences not elsewhere classified; Near-Unity Photoluminescence Quantu.; QD-LED; ensemble level; Core; PLQY; toxic-metal-free; Toxic-Metal-Free Quantum Dot; Neuroscience; Cancer; Biological Sciences not elsewhere classified

There is no literature report of simultaneously achieving near-unity PLQY (ensemble level) and highly suppressed blinking (ultrasensitive single-particle spectroscopy (SPS) level) in a toxic-metal-free QD. In this Letter we report accomplishing near-unity PLQY (96%) and highly suppressed blinking (>80% ON fraction) in a toxic-metal-free CuInS2/ZnSeS Core/Alloy-Shell (CAS) QD. In addition, (i) gigantic enhancement of PLQY (from 15% (Core) to 96% (CAS QD)), (ii) ultrahigh stability over 1 year without significant reduction of PLQY at the ensemble level, (iii) high magnitude (nearly 3 times) of electron detrapping/trapping rate, and (iv) very long ON duration (∼2 min) without blinking at the SPS level enable this ultrasmall (∼3.3 nm) CAS QD to be quite suitable for single-particle tracking/bioimaging. A model explaining all these excellent optical properties has been provided. This ultrabright CAS QD has been successfully utilized toward fabrication of low-cost microcontroller-based stable and bright yellow and white QD-LEDs.