Cesium Lead Halide Perovskite Quantum Dots as a Photoluminescence Probe for Metal Ions.

Perovskite structured CsPbX3 (X = Cl, Br or I) quantum dots (QDs) have attracted great attention in the past few years for appealing application potentials in photovoltaic and optoelectronic devices. In this report, the CsPbX3 QDs are shown to perform as a new probe for metal ions with high sensitivity, high selectivity and instant response by the quenching or enhancing of the photoluminescence (PL). Through experimental and calculation efforts, the probing mechanisms are investigated. A wide probing window for Cu2+ and Yb3+ ions ranging from 2 × 10-9 to 2 × 10-6 m is exhibited for CsPbBr3 QDs. In practice, the CsPbBr3 QDs are successfully applied for fast probing Cu2+ ions in edible oils and vehicle lubricating oils with the precision consistent to the values measured by inductively coupled plasma (ICP). Thus, it provides a promising powerful tool in detecting certain metal ions in biological and industrial organic solution systems.

Ultrafast Solar-Blind Ultraviolet Detection by Inorganic Perovskite CsPbX3 Quantum Dots Radial Junction Architecture.

Inorganic CsPbX3 (X = Cl, Br, I, or hybrid among them) perovskite quantum dots (IPQDs) are promising building blocks for exploring high performance optoelectronic applications. In this work, the authors report a new hybrid structure that marries CsPbX3 IPQDs to silicon nanowires (SiNWs) radial junction structures to achieve ultrafast and highly sensitive ultraviolet (UV) detection in solar-blind spectrum. A compact and uniform deployment of CsPbX3 IPQDs upon the sidewall of low-reflective 3D radial junctions enables a strong light field excitation and efficient down-conversion of the ultraviolet incidences, which are directly tailored into emission bands optimized for a rapid photodetection in surrounding ultrathin radial p-i-n junctions. A fast solar-blind UV detection has been demonstrated in this hybrid IPQD-NW detectors, with rise/fall response time scales of 0.48/1.03 ms and a high responsivity of 54 mA W-1 @200 nm (or 32 mA W-1 @270 nm), without the need of any external power supply. These results pave the way toward large area manufacturing of high performance Si-based perovskite UV detectors in a scalable and low-cost procedure.