Scalable Fabrication of Metal Halide Perovskites for Direct X-ray Flat-Panel Detectors: A Perspective

Abstract

Metal halide perovskites are promising for direct X-ray detection applications thanks to their high X-ray absorption capability and excellent charge carrier transport. Single-pixelated perovskite Xray detectors have hitherto demonstrated excellent device performance, including high sensitivity and detectivity. On the other hand, multipixel flat-panel detectors (FPDs) that enable 2D X-ray imaging are undeveloped due to challenges in scalable deposition processes. In this perspective, we summarize promising scalable perovskite deposition processes and discuss the challenges and opportunities toward direct X-ray FPD applications.

Thermally Activated Delayed Fluorescence Zirconium‐Based Perovskites for Large‐Area and Ultraflexible X‐ray Scintillator Screens

“…Besides, the detection limit of Cs 2 ZrCl 6 @PDMS flexible films is 65 nGy air s −1 under a signal‐to‐noise ratio (SNR) of 3, much lower than that of the LYSO:Ce (557 nGy air s −1 ), and about 85× lower than the typical medical X‐ray diagnostic requirement (5.5 µGy s −1 ). [ 52–55 ] Figure S15, Supporting Information shows a highly linear relationship between RL intensity and X‐ray dose rate for the flexible films under higher excitation, which is beneficial for obtaining good imaging contrast.…”

Halide Perovskite: A Promising Candidate for Next‐Generation X‐Ray Detectors

“…[ 19,20 ] High sensitivity indicates that X‐rays can induce a large photocurrent for a given irradiation dose rate, and it has a close relationship with the imaging quality. Generally, sensitivity ( S ) is determined by the collected charge per unit area under irradiation, which can be calculated by [ 8,21 ] $$$$\begin{equation}S = \frac{{{I}_{\rm{p}} - {I}_{\rm{d}}}}{{D \times A}}\end{equation}$$$$where I p and I d are the photocurrent and the dark current, respectively, while D is the X‐ray dose rate, and A is the effective detection area. Therefore, one approach to improve the sensitivity is to increase the applied electric field, which can increase carrier separation and reduce recombination (increasing I p ).…”

A-Site Cation Engineering of Ruddlesden–Popper Perovskites for Stable, Sensitive, and Portable Direct Conversion X-ray Imaging Detectors

“…However, the number of reports on perovskite integration with TFT can be counted on one hand, and most of the perovskite-based detectors were single-pixel without TFT integration. 6 In 2017, Kim et al fabricated an 830 μm thick MAPbI 3 film on the TFT array using the blade-coating method and developed the first perovskite FPDs enabling Xray imaging. 11 However, the blade-coated perovskite film inevitably includes many pores due to evaporation of the solvent from a thick wet film.…”

“…Halide perovskites are promising photoconductive layers for direct X-ray detection applications due to their excellent X-ray absorption, high mobility, and facile preparation. − Perovskite X-ray detectors have demonstrated excellent detection performance, which show >100-fold higher sensitivity and <100-fold lower limit of detection (LoD) compared to those of commercialized a-Se X-ray detectors. − These facts make a perovskite X-ray detector a competitive candidate for next-generation X-ray detectors, which is favorable for realizing truly personalized patient care through reducing health risks to patients. − …”

“…Flat-panel X-ray detectors (FPDs) are in high demand for realizing medical imaging, a nondestructive test, and security inspection. , To achieve FPDs, perovskite photoconductive layers should be integrated with a commercialized thin film transistor (TFT) or complementary metal oxide semiconductor transistor arrays (CMOS), which can take two-dimensional (2D) multipixel images via a readout integrated circuit (ROIC). However, the number of reports on perovskite integration with TFT can be counted on one hand, and most of the perovskite-based detectors were single-pixel without TFT integration . In 2017, Kim et al fabricated an 830 μm thick MAPbI 3 film on the TFT array using the blade-coating method and developed the first perovskite FPDs enabling X-ray imaging .…”