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[Display omitted] • BN nanosheets act as a barrier, inhibiting ion migration within perovskite layers. • BN also improved charge transport and carrier mobility. • Perovskite photodiodes incorporated with BN exhibit exceptional X-ray stability. Metal halide perovskites have been widely used in optoelectronic applications due to their excellent optoelectronic properties. However, ensuring their stability during operation remains a significant challenge. In this study, we investigated the charge carrier dynamics of perovskite films and devices, comparing those with and without the insertion of boron nitride on the grain boundaries. It was revealed that the charge transport and stability could be significantly enhanced with the present of boron nitride nanosheets on the grain boundaries. The incorporation of boron nitride led to a substantial improvement in charge carrier mobility and lifetime, without any noticeable changes in phase segregation or photostability. Moreover, the perovskite detectors incorporating boron nitride exhibited suppressed ion migration and dark current, while demonstrating an enhanced photoresponse and radiation exposure capability. These findings indicate that the addition of insulating boron nitride nanosheets acts as a stabilizer, enhancing the stability of both the perovskite thin films and the devices. Additionally, the incorporation of boron nitride significantly improved the device performance benefiting from the enhanced charge transport, indicating that the boron nitride nanosheets enhanced perovskite photodiodes possess great potential for X-ray detection and imaging. [ABSTRACT FROM AUTHOR]

[Display omitted] CsPbBr 3 -CsPb 2 Br 5 wafer is obtained by water-assisted coprecipitation method, and a spray-coating method is further utilized to convert it into CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafer, which exhibits superior performance and reliability of X-ray detection. • Water-assisted coprecipitation is proposed to prepare high-quality CsPbBr 3 -CsPb 2 Br 5 powder. • CsPbBr 3 -CsPb 2 Br 5 wafer is obtained by pressure-induced aggregation of the powder. • Spray-coating of CsI/H 2 O onto CsPbBr 3 -CsPb 2 Br 5 wafer can convert it into CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafer. • X-ray detector with the composite wafer exhibits much improved performance and reliability. Lead halide perovskite wafers with large lateral size, controllable thickness, and desirable optoelectronic characteristics are promising for X-ray detectors. Herein, CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafers are prepared via water-assisted coprecipitation and spray coating. The preparation involved pressure-induced aggregation of the CsPbBr 3 -CsPb 2 Br 5 powder produced through coprecipitation using of H 2 O/MeOH mixed solvent into CsPbBr 3 -CsPb 2 Br 5 wafers, followed by spraying a CsI/H 2 O solution onto the wafer surface to transform it into a CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafer. Multiple favorable properties, including compact surface, high crystallinity, excellent carrier transportation, large/adjustable size, low cost, and mass producibility, can be identified for the CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafer. An X-ray detector with high performance and excellent stability is realized with this wafer. It yields high resistivity (ρ; 1.3 × 109 Ω cm−2, exceptional carrier mobility (μ)/lifetime (τ) (μτ) product (1.01 × 10−3 cm2 V−1), high sensitivity (20555.1 μC Gy air −1 cm−2), and low detection limit (127.7 nGy s−1). Hence, our research provides a reliable strategy for optimizing the structure and performance of perovskite wafer-based X-ray detectors and enabling mass preparation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two semiconductive Ba(II)-based CPs 1 and 2 with small exciton binding energy (E b) values were successfully prepared. • The 2 -based film detector achieves superior direct X-ray detection performance among CP-based detectors. • The enhanced π-π interactions are beneficial to exciton separation and charge carrier transport irradiated by X-ray. High-performance and low-cost X-ray detector is crucial for medical imaging, nondestructive industrial detection and security checks. Semiconductive coordination polymers (CPs) with designable structures, tunable property and high cost-effectiveness have recently emerged as promising materials in direct X-ray detection. However, due to the strong Coulomb interactions between photogenerated electrons and holes, most of CPs often exhibit high exciton binding energies, resulting in relatively insufficient exciton dissociation as well as low photocurrent output and detection sensitivity in turn. Here, we employed the anthracene-based ligand to obtain two semiconductive CPs, {[Ba 2 (Hadba) 4 (DMF) 8 ]·DMF} n 1 (H 2 adba = 4,4′-(9,10-anthracenediyl)dibenzoic acid, DMF = N , N -dimethylformamide) and [Ba(Hadba) 2 (DMA) 4 ] n 2 (DMA = N , N -dimethylacetamide). Both of them can effectively convert X-ray into electrical signals. Compared with compound 1 , compound 2 has a reduced E b (44.9 meV) caused by the reinforced π-π interactions, contributing to the facilitated carrier transport, a significant enhance in mobility-lifetime product (μτ) and detection sensitivity irradiated by X-ray. Based on the optimized detection performance, we prepared a flexible 2 -based composite film detector with a low detection of 1.02 μGy/s that meets the standard for medical imaging. In particular, this film-based detector achieves a high sensitivity of 137.31 μCGy−1 cm−2 and μτ product of 3.03 × 10−3 cm2 V−1, which are superior to all previously reported CP-based detectors and much higher than commercial α -Se. Simultaneously, a 5 × 5 pixelated X-ray imaging device was further constructed to show its potential application in direct X-ray detection and imaging. [ABSTRACT FROM AUTHOR]

AgI incorporated perovskite X-ray detectors were fabricated based on the spray-coating technique. The effect of AgI incorporation on the optoelectronic properties was systematically investigated. With suitable amount of AgI content, metal halide perovskite exhibited improved crystallinity, charge carrier mobility, lifetime, and X-ray sensitivity. [Display omitted] • Perovskite thick films were fabricated via spray-coating process. • The effect of AgI incorporation was carefully evaluated and optimized. • X-ray detectors based on the spray-coated perovskite thick junctions were fabricated. • High X-ray sensitivity, low detection limit and fast response were achieved. Metal halide perovskites have emerged as a promising candidate for ionizing radiation detection, thanks to the facile fabrication, excellent optoelectronic properties and high attenuation coefficient. In order to fully absorb the incident X-ray photons, X-ray detectors require relatively thick active layers. However, it is challenging to obtain thick perovskite films based on conventional solution-based techniques, due to the limited solubility and viscosity of the perovskite precursors. In this work, we introduced spray-coating to deposit perovskite films on various substrates, and achieved tunable and thick films. On the other hand, the charge transport is another issue limiting the device performance of perovskite X-ray detectors. Compared with conventional inorganic semiconductors, hybrid perovskites possess relatively poor charge carrier mobility and lifetime. To address this issue, we incorporate AgI within the perovskite precursor, and systematically investigated their optoelectronic properties. It was found that the optimized AgI incorporated perovskite films exhibited the highest mobility-lifetime product, resulted X-ray sensitivity up to 3433 μGy air −1 cm−2 and ultra-low detection limit of 3.5 nGy air s−1, suggesting great potential for X-ray detection. [ABSTRACT FROM AUTHOR]