Formamidinium Lead Halide Perovskite Nanocomposite Scintillators

Abstract

While there is great demand for effective, affordable radiation detectors in various applications, many commonly used scintillators have major drawbacks. Conventional inorganic scintillators have a fixed emission wavelength and require expensive, high-temperature synthesis; plastic scintillators, while fast, inexpensive, and robust, have low atomic numbers, limiting their X-ray stopping power. Formamidinium lead halide perovskite nanocrystals show promise as scintillators due to their high X-ray attenuation coefficient and bright luminescence. Here, we used a room-temperature, solution-growth method to produce mixed-halide FAPbX3 (X = Cl, Br) nanocrystals with emission wavelengths that can be varied between 403 and 531 nm via adjustments to the halide ratio. The substitution of bromine for increasing amounts of chlorine resulted in violet emission with faster lifetimes, while larger proportions of bromine resulted in green emission with increased luminescence intensity. By loading FAPbBr3 nanocrystals into a PVT-based plastic scintillator matrix, we produced 1 mm-thick nanocomposite scintillators, which have brighter luminescence than the PVT-based plastic scintillator alone. While nanocomposites such as these are often opaque due to optical scattering from aggregates of the nanoparticles, we used a surface modification technique to improve transmission through the composites. A composite of FAPbBr3 nanocrystals encapsulated in inert PMMA produced even stronger luminescence, with intensity 3.8× greater than a comparative FAPbBr3/plastic scintillator composite. However, the luminescence decay time of the FAPbBr3/PMMA composite was more than 3× slower than that of the FAPbBr3/plastic scintillator composite. We also demonstrate the potential of these lead halide perovskite nanocomposite scintillators for low-cost X-ray imaging applications.

Development and characterisation of caesium lead halide perovskite nanocomposite scintillators for X-ray detection

“…In our samples the peak intensities of the dispersions increased with the amount of Br present. Taking the CsPbCl 1.5 Br 1.5 peak intensity as 100%, the CsPbClBr 2 had an intensity of 175% and the CsPbBr 3 200% as shown in Supplementary Figure S1A The decreased light yield for lead halide perovskites with chlorine present has also been seen in studies of organic FA lead halide nanoparticles [4].…”

“…CsPbX 3 nanoparticles have been recently shown to act as a scintillator, with a light yield reported to be 17,000 photons per MeV [19]. Composite perovskite scintillators are an active area of research, with recent work on FAPbX 3 -PMMA composite scintillators reported as a viable direct X-ray imaging device [4]. In this work we report the production and analysis of 1 mm thick nanocomposite materials loaded with commercially available CsPbX 3 nanoparticles, with a high X-ray stopping power and transmission.…”

A Review on Lead‐Free Perovskites for X‐Ray Detection and Imaging

“…By adjusting the proportion of halogen atoms in lead halide perovskite, this work not only ingeniously solves the shortcoming of single wavelength of traditional inorganic scintillator, but also effectively improves the problem of low cut‐off efficiency of plastic scintillator. [ 23 ]…”

“…atoms in lead halide perovskite, this work not only ingeniously solves the shortcoming of single wavelength of traditional inorganic scintillator, but also effectively improves the problem of low cut-off efficiency of plastic scintillator. [23] The other method is based on direct X-ray detection of semiconductor microcrystals, as shown in the Figure 1b, which can directly convert radiation into current. [24][25][26] The simple conversion mode widen the linear response range of the direct X-ray detector, accelerate the response, and the spatial resolution and energy resolution has improved greatly, which can work with the indirect X-ray detector to obtain higher efficiency.…”

Flexible perovskite scintillators and detectors for X-ray detection

“… 10 , 11 , 12 Meanwhile, they have a relatively high atomic number, moderate density and tunable bandgaps with some of the properties even superior to conventional materials, making them great candidates as active materials in X-ray detectors. 13 Their relatively low deposition temperature also makes the realization of flexible X-ray detectors possible. Actually, MHPs have already been regarded as an alternative material in X-ray detectors with some magnificent work being already published.…”