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.