Single-Crystalline Perovskite Nanowire Arrays for Stable X-ray Scintillators with Micrometer Spatial Resolution

Abstract

X-ray scintillation detectors based on metal halide perovskites have shown excellent light yield, but they mostly target applications with spatial resolution at the tens of micrometers level. Here, we use a one-step solution method to grow arrays of 15-μm-long single-crystalline CsPbBr 3 nanowires (NWs) in an AAO (anodized aluminum oxide) membrane template, with nanowire diameters ranging from 30 to 360 nm. The CsPbBr 3 nanowires in AAO (CsPbBr 3 NW/AAO) show increasing X-ray scintillation efficiency with decreasing nanowire diameter, with a maximum photon yield of ∼5 300 ph/MeV at 30 nm diameter. The CsPbBr 3 NW/AAO composites also display high radiation resistance, with a scintillation-intensity decrease of only ∼20–30% after 24 h of X-ray exposure (integrated dose 162 Gy air ) and almost no change after ambient storage for 2 months. X-ray images can distinguish line pairs with a spacing of 2 μm for all nanowire diameters, while slanted edge measurements show a spatial resolution of ∼160 lp/mm at modulation transfer function (MTF) = 0.1. The combination of high spatial resolution, radiation stability, and easy fabrication makes these CsPbBr 3 NW/AAO scintillators a promising candidate for high-resolution X-ray imaging applications.

Free-Standing Metal Halide Perovskite Nanowire Arrays with Blue-Green Heterostructures

“…We tried different AAO pore diameters in a range from 10 to 350 nm but only obtained free-standing nanowires in the range from 200 to 350 nm. However, we did manage to grow nanowires inside the pores for all diameters, , and it is quite possible that thinner free-standing nanowires could be obtained using optimized growth conditions.…”

“…For example, free-standing vertically aligned nanowires of Si, ZnO, GaAs, and InP have achieved excellent performance in various optoelectronic fields. − However, the growth of free-standing vertically aligned MHP nanowire arrays is difficult. Compared with the numerous studies on growth of horizontal MHP nanowire arrays, ,− there are only a few reports of vertically aligned nanowire arrays, and those mostly concern nanowires physically confined inside various templates such as anodized aluminum oxide (AAO). − A few studies have reported free-standing MHP nanowires by solution extrusion and vapor–liquid–solid methods, but the alignment of the obtained NWs was not satisfactory. The solution extrusion method works only when the precursor can form an intermediate phase, while the vapor–liquid–solid growth needs the assistance of a metal catalyst and high temperature .…”

Improved extraction efficiency of CsPbBr3 perovskite light-emitting diodes due to anodic aluminum oxide nanopore structure

“…Therefore, the Stoke shift of 8 nm is caused by the thermal energy form the excitation laser. The blue-shift of approximately 4 nm for the CsPbBr 3 perovskite film with and without AAO films may be caused by the pore size effect caused by the bandgap modulation 23 – 25 .

Figure 4 ( a ) Absorbance and ( b ) photoluminescence (PL) spectra of CsPbBr 3 perovskite film on and in AAO films.

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Ultrathin, Transparent, and High Density Perovskite Scintillator Film for High Resolution X‐Ray Microscopic Imaging

“…For example, many perovskite NCs‐based scintillators screen have been developed and show the potential for X‐ray imaging with the advantage of low‐cost, easy for preparation, and high detection sensitivity. [ 12 , 19 , 22 , 24 , 30 , 44 ] However, many scintillator films preparation methods [ 23 , 31 , 45 , 46 , 47 , 48 ] require the addition of auxiliary film‐forming geopolymers, which causes the low equivalent density of scintillator material in the film and thus results in the low RL intensity. To ensure the enough light output, the thick film is required but is usually opaque, which greatly increase the light scattering and seriously reduce the imaging resolution.…”