Inorganic halide perovskite thin-film X-ray detectors have attracted great research interest in recent years due to their high sensitivity, low detection limit, and facile fabrication process. The poor crystal quality of the thin film with uncontrollable thickness and low background voltage during detection limits its practical application. Here, a high-quality CsPbBr3–xIx (x = 0, 1) columnar crystal film is prepared by an improved melt-confined method with a porous anodic aluminum oxide (AAO) template, which stabilizes the disorder perovskite systems of CsPbBr2I by stress. The AAO-CsPbBr3–xIx (x = 0) detectors exhibit high detection accuracy and photoelectric conversion capability with an ultrahigh sensitivity of 32,399.5 μC·Gyair–1·cm–2 at 2142.9 V mm–1 under 20 kVp X-rays and 19,217.4 μC·Gyair–1·cm–2 with a higher background electric field of 6666.7 V mm–1 for AAO-CsPbBr3–xIx (x = 1). Moreover, the AAO-CsPbBr3–xIx (x = 1) film detector acquires a lower detection limit of 7.65 nGy·s–1 and a higher X-ray imaging spatial resolution of 1.6 LP/mm and 8.6 nGy·s–1 and 1.4 LP/mm for AAO-CsPbBr3–xIx (x = 0). The facile, high-quality columnar crystal film devices display great potential for low-energy and low-dose X-ray imaging in flat panel detection applications.
A simple and efficient light-assisted method is employed to prepare powder samples of all-inorganic mixed-perovskite CsPbBr 3-x I x from CsPbBr 3 by ion exchange in aqueous HBr/KI solution such that the concentration of I in a sample particle decreases on going from the surface to the interior. CsPbBr 3-x I x /Pt, namely, CsPbBr 3-x I x samples loaded with Pt nanoparticles, shows a high performance for the hydrogen evolution under visible-light irradiation in aqueous HBr solution saturated with CsPbBr 3 . The H 2 evolution rate of the CsPbBr 3-x I x /Pt powders (200 mg) is determined to be 224 μmol h −1 , under 120 mW cm -2 visible-light (λ ≥ 420 nm) illumination. The CsPbBr 3-x I x samples have a high stability, with no apparent decrease in the catalytic activity after 50 h of repeated H 2 evolution experiments. The apparent quantum efficiency of CsPbBr 3-x I x /Pt is determined to be 2.15% under the irradiation of 450 nm light.
Although lead halide perovskite (LHP) nanocrystals (NCs) are considered propitious materials due to their extraordinary optoelectronic properties, the scalability of synthesis and poor ambient stability hinder their commercial applications. Herein, we develop a facile and universal room-temperature (RT) protocol for the synthesis of red-emitting all-inorganic CsPbBr3−xIx perovskite NCs by the mediation of capping ligands. The emission wavelength can be tuned in the range of 598–651 nm by tailoring the PbBr2 : PbI2 precursor ratios and the amounts of ligands. Interestingly, the introduction of ligands such as 3-mercaptopropionic acid (MPA) and thioglycolic acid (TGA) heavily improves the stability of the as-synthesized NCs against water, heat stress and UV irradiation, which is due to surface passivation. This work offers a reliable and scalable reference for tuning red-emissive perovskite NCs with improved environmental stability, which will accelerate their commercial application process in optoelectronic fields.
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