Advances in Metal Halide Perovskite Scintillators for X-Ray Detection

Abstract

The relentless pursuit of advanced X-ray detection technologies has been significantly bolstered by the emergence of metal halides perovskites (MHPs) and their derivatives, which possess remarkable light yield and X-ray sensitivity. This comprehensive review delves into cutting-edge approaches for optimizing MHP scintillators performances by enhancing intrinsic physical properties and employing engineering radioluminescent (RL) light strategies, underscoring their potential for developing materials with superior high-resolution X-ray detection and imaging capabilities. We initially explore into recent research focused on strategies to effectively engineer the intrinsic physical properties of MHP scintillators, including light yield and response times. Additionally, we explore innovative engineering strategies involving stacked structures, waveguide effects, chiral circularly polarized luminescence, increased transparency, and the fabrication of flexile MHP scintillators, all of which effectively manage the RL light to achieve high-resolution and high-contrast X-ray imaging. Finally, we provide a roadmap for advancing next-generation MHP scintillators, highlighting their transformative potential in high-performance X-ray detection systems.

Keywords: Engineering strategies; Metal halide perovskites; Radioluminescence properties; Scintillators; X-ray detection.

Fig. 1

Mechanism of MHP Scintillators for X-ray Detection. a Three-stage scintillation processes: conversion of X-rays to UV/visible photons, transport of charge carriers, and luminescence via radiative recombination. b Exciton recombination mechanism: Excitons formed by electron–hole pairs migrate and emit photons upon recombination. c STE emission: Electrons and holes localize in a distorted lattice, forming a low-energy bound state that leads to longer lifetimes and broader emission. d TADF emission: Triplet excitons convert to singlet states via RISC, resulting in delayed radiative emission. e LPRL emission: Excitons are captured by trap states and released over time through thermal activation, leading to persistent radiative emission

Fig. 2

Scintillator performances of MHP NCs. a Structural schematic and corresponding TEM image of synthesized CsPbBr₃ QDs. b Tunable X-ray-induced luminescence spectra of CsPbX₃ QDs. c RL intensity versus X-ray dose rate for CsPbBr₃ QDs. d RL decay kinetics of CsPbBr₃ QDs under ¹³⁷Cs irradiation. e Multicolor X-ray scintillation from CsPbX₃ QDs: orange (CsPbBr₂I), green (CsPbBr₃), blue (CsPbClBr₂) [58]. f TEM image of assembled CsPbBr₃ nanoplatelets. g Pulse height spectra comparing CsPbBr₃ nanoplatelets with LuAG:Ce scintillator [59]. h Photographs of CsPbBr₃ CG. i Normalized RL intensity under prolonged X-ray exposure for CsPbBr₃ CG, CsI: Tl, and BGO. j Photographs of a transistor panel in a cellphone and a fish recorded under daylight and X-ray irradiation, respectively [38, 60]

Fig. 3

Scintillator performances of 2D MHPs. a Crystal structure representation of MAPbX₃ (X = I, Br) 3D, and (EDBE)PbCl₄ 2D MHPs. b Temperature dependence of the light yields of MAPbI₃, MAPbBr₃, and (EDBE)PbCl₄ at various temperature [19]. c Crystal structure of the 2D layered (PEA)₂PbBr₄. d RL comparison of the (PEA)₂PbBr₄ SC, powder, and MC thin film and CsI: Tl SC under the same X-ray irradiation. e RL decay time comparison of (PEA)₂PbBr₄ SC and CsI:Tl [63]. f Crystal structures of 2D hybrid MHP with self-assembled 2D multiple quantum well structure. g Design strategy of enhancing exitonic dielectric confinement by choosing organic amines with low refraction index (n). h Comparison of the light yield of sub-nanosecond scintillators [64]

Fig. 4

Scintillator performances of STEs MHPs. a Crystal structure of Rb₂CuBr₃. b PL spectrum of Rb₂CuBr₃ under 300 nm excitation and PLE spectra monitored at emission wavelengths from 350 to 450 nm. c RL spectrum of Rb₂CuBr₃ under 30 keV X-ray excitation and wavelength-dependent photon detection efficiency of the silicon photomultiplier (SiPM). d ET in quasi-2D MHPs contributes to a larger Stokes shift. e The calculated self-absorption coefficient of the quasi-2D perovskite film [92]. f RL spectra of Cs₂Ag_0.6Na_0.4In_0.85Bi_0.15Cl₆, LuAG: Ce and CsI: Tl scintillators. g Stokes shift of Cs₂Ag_0.6Na_0.4In_1-yBi_yCl₆ with different Bi³⁺ contents [67]. h Absorption and PL spectra of Cs₂HfCl₆. i RL spectra of Cs₂HfCl₆ film and LYSO: Ce [69]

Fig. 5

Scintillator performance of Mn²⁺-doped MHPs. a Schematic diagram of Mn²⁺-doped BA₂PbBr₄. b Absorption and PL spectra of undoped and 10% Mn²⁺-doped BA₂PbBr₄. c Comparison of the X-ray scintillation light yield of BA₂PbBr₄:10% Mn²⁺ with several previously reported MHP scintillators [40]. d Absorption and PL spectra of CsPb(BrCl)₃: Mn²⁺ NCs. e Radiograph of CsPbBrCl₂: Mn²⁺ NC under fast neutron irradiation as compared with FAPbBr₃ NCs and a commercial ZnS: Cu screen. f Light output performance of FAPbBr₃ NCs [124]

Fig. 6

Lanthanide-doped MHP scintillators. a Partial 4f-energy level diagram for trivalent lanthanide activators. b Main luminescent transitions of the lanthanide activators in the electromagnetic spectrum [129]. c RL spectra of CsPbBr₃ CG, CsPbBr₃: Eu³⁺ CG under X-ray excitation. d Steady-state light yield calculation of CsPbBr₃: Eu³⁺ CG, commercial LuAG: Ce. e Absorption spectra, visible emission spectra and near-infrared emission spectra (λ_ex = 365 nm) of lanthanide-free and -doped CsPbCl₃. f Comparison of the light output between CsPbCl₃: Yb.³⁺ scintillators and several typical scintillators [70]

Fig. 7

ET strategies for MHP scintillators. a Schematic depiction of composited scintillator for constructing the ET process. b Sketch of a CsPbBr₃ NCs sensitizing the perylene dyad 1. c Molar extinction coefficient and PL spectra of CsPbBr₃ NCs and perylene dyad 1 [131]. d Diagram of ET between the CsPbBr₃ NWs and PM597 organic dye molecules. e The optical absorption and PL spectra of CsPbBr₃ NWs, PM597 organic dye, and CsPbBr₃ NWs/PM597 organic dye [132]. f Schematic of two kinds of structural configurations, IH-type CsPbBr₃ and PM-type CsPbBr₃. g Calculated FRET efficiency of IH-type CsPbBr₃ and PM-type CsPbBr₃ scintillator [133]

Fig. 8

Crystalline enhancement strategies for MHP scintillators. a Schematic diagram of the A-site management strategy. b XRD patterns of MA-based MHP films with varying NH₄Br concentrations [134]. c XRD patterns of precursor glass (PG), CsPbBr₃ and CsPbBr₃: Eu³⁺ CG. TEM images of d CsPbBr₃ and e CsPbBr₃: 1.5%Eu.³⁺ CG [37]. f Schematic illustration of the fabrication process for MHP microcrystalline film via ultrasound-assisted crystallization and hot pressing [135]

Fig. 9

Delayed X-ray performance of the scintillators. a Mechanism diagram of X-ray-induced multi stimulus-induced de-trapping process. b Schematic diagram showing non-destructive inspection of 3D curved objects enabled by X-PersL behavior of the scintillators. c X-PersL photographs of A) CsCdCl₃: 5%Mn²⁺, B) CsCdCl₃: 5%Mn²⁺, 0.1%Zr⁴⁺, and C) CsCdCl₃: 5%Mn²⁺, 0.1%Ti⁴⁺. d TSL images of annulus electric conduction link using the flat panel (left) and curved panel CsCdCl₃: 5%Mn²⁺, 0.1%Zr⁴⁺@PDMS film (5 cm × 2.5 cm). The image read out temperature is 100 °C [144]. e Schematic diagram and photographs of the as-obtained NaLuF₄: Ho³⁺ NCs or real-time and delayed-time (ML) of X-ray dose detection [145]. f Photographs of the time-dependent X-PersL, PSL, and TSL features of the as-obtained NaLuF₄: Tb.³⁺ NCs [109]

Fig. 10

Scintillator performances of stacked MHPs. a Schematic of a conventional energy-integrated X-ray imaging system and large-area multi-energy FPXI system based on stacked multilayer scintillators. b X-ray absorption coefficients of FAPbI₃, C₄H₁₂NMnCl₃, (C₈H₂₀N)₂MnBr₄ and Cs₃Cu₂I₅. c RL spectra of FAPbI₃, C₄H₁₂NMnCl₃, (C₈H₂₀N)₂MnBr₄, and Cs₃Cu₂I₅ scintillators. d The proportion of the four energy X-rays contributing to the light emitted by each scintillator and the corresponding multi-energy X-ray images at four energy channels at 5, 15, 30, and 50 keV [73]. e Schematic of the working principle and the corresponding color evolution of the TFB sandwich structure scintillator [149]. f Schematic of the working principle and the corresponding color evolution of the MEXI system featuring a six-layered architecture scintillator. g MTF curves of the MEXI system under low-, medium-, and high X-ray tube voltages [93]

Fig. 11

Scintillator performances of waveguided MHPs. a Light propagation mechanisms and results of conventional nonstructured scintillators and structured capillary needle-like array scintillators in X-ray imaging [154]. b Cross-sectional SEM image of Cs₃Cu₂I₅-AAO scintillator. c The MTF values of Cs₃Cu₂I₅-AAO, HP-Cs₃Cu₂I₅, and GOS [155]. d Spatial resolution of the pixelated CsPbBr₃-AAO arrays scintillation. e X-ray imaging of memory card with the pixelated CsPbBr₃-AAO arrays [156]. f X-ray image of a microresolution chart. The right one is the gray value profiles along the cyan and green lines extracted from the X-ray image of the microresolution chart [154]

Fig. 12

Scintillator performances of CPL MHPs. a Conceptual illustration of the minimization of optical crosstalk by CPRL. b The crystal structures of R-3APP and S-3APP. c Schematic illustration of the experimental setup for verifying the CPRL measurement. d The polarization-dependent RL of chiral S-3APP and R-3APP. e The left-handed and right-handed RL emission crystals show bright and dark changes when rotating the linearly polarized plate [159]

Fig. 13

Development of the transparent MHP scintillator. a Schematic diagram of the surface modification and polymerization process for preparing the CsPbBr₃/PBMA nanocomposites [166]. b Scheme of the scintillator film synthesis procedure by the suction filtration method and the corresponding c SEM and d optical images [169]. e Schematic diagram of the in situ growth of CsPbBr₃-based polymer–ceramics. f Photographs of the one-step in situ growth of CsPbBr₃ QDs from transparency matrix under UV illumination [38]. g Fabrication process of TPP₂MnBr₄ ceramic scintillator via the SCS process. h Photographs of as-obtained TPP₂MnBr₄ ceramic scintillator [170]

Fig. 14

Scintillator performances of curved MHPs. a Detector structure sketches: fat panel glass substrate and a flexible polyimide substrate [160]. b The diagram of the X-ray imaging under flat and bending states. c The difference of the corresponding indirect X-ray imaging ways, and the corresponding X-ray images of a bend target with the attached and projection imaging, respectively, and d their corresponding MTF of the specified location (A, B, C, and D) of the target [38]. e X-ray images of flexible copper grid taken by flexible Cs₂Cu₂I₅ film under flat and bending states. f MTF of the flexible Cs₂Cu₂I₅ film [174]

Fig. 15

Technical roadmap of perovskite scintillators over the next five years. ML, mechanical learning; Al, artificial intelligence