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

Abstract

Inorganic CsPbX (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 CsPbX 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 CsPbX 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 @200 nm (or 32 mA W @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.

Exploring a Polar Two‐dimensional Multi‐layered Hybrid Perovskite of (C5H11NH3)2(CH3NH3)Pb2I7 for Ultrafast‐Responding Photodetection

“…Accordingly, ultrafast responding rise time ( τ r ) and fall time ( τ f ) were achieved to be ≈1.52 and 1.67 μs, respectively. Compared with the reported values in the literatures, the responding speed of our device is faster by 2–4 orders than other 2D layered OIHPs photodetector, and even quicker than the top‐ranking inorganic perovskite competitors, including 2D CsPbBr 3 nanosheets ( τ = 19/25 μs), CsPbX 3 quantum dots ( τ = 0.48/1.03 ms) and PbS nanoplates‐graphene ( τ = 24/59 ms) . This highly‐fast responding feature indicates the great potentials of EMA for high‐speed photodetection.…”

Low‐dimensional nanomaterial/Si heterostructure‐based photodetectors

“…Recently, Xu et al designed a hybrid device that combined inorganic perovskite QDs with Si nanowire radial junctions and demonstrated a photodetector sensitive toward solar-blind UV detection. 38 The inorganic perovskite QDs were conformally decorated on the sidewalls of the nanowire junctions, thereby enabling powerful lightfield excitation and absorption. Such a design can effectively trap the downconverted photon signals, and the surrounding Si nanowire junctions detected the signal at zero bias, with a responsivity of 54 mA W −1 at 200 nm and rise/decay times of only 0.48/1.03 ms. Another example comes from Mihalache, 39 who coupled a Si nanowire array with newly designed graphene quantum dots (GQDs).…”

Recent Progress of All‐Bromide Inorganic Perovskite Solar Cells

“…Currently, the unprecedented development of organic–inorganic hybrid perovskite solar cells (OIH‐PSCs) has drawn much attention because of high efficiency, low‐cost processing techniques, and abundant availability of raw materials . The power conversion efficiency (PCE) of OIH‐PSCs, in the past decade, increased rapidly from 3.8% as reported in 2009 to a certified record of 25.2% in 2019 .…”