Search

Perovskite single crystals are actively studied as X-ray detection materials with enhanced sensitivity. Moreover, the feasibility of using perovskites for self-powered devices such as photodetectors, UV detectors, and X-ray detectors can significantly expand their application range. In this work, the charge carrier transport and photocurrent properties of MAPbBr3 single crystals (MSCs) are improved by the mechanochemical surface treatment using glycerin combined with an additional electrode design that forms an ohmic contact. The sensitivity of MSC-based detectors and pulse shape generated by X-rays are enhanced at various bias voltages. The synthesized MSC detectors generate direction-dependent photocurrents, which indicate the presence of a polarization-induced internal electric field. In addition, photocurrent signals are produced by X-rays with energies greater than 1 MeV under a zero-bias voltage. This work demonstrates a high application potential of perovskites as self-powered detectors for X-rays with energies exceeding 1 MeV. [ABSTRACT FROM AUTHOR]

Perovskite quantum dots (PEQDs) are next-generation quantum dot materials that have attracted attention in various areas such as display, radiation scintillator, and photodetector. However, PEQD defects that occur for various reasons hinder the commercialization of PEQDs. Herein, we reported a new strategy for a hybrid ligand comprising 1-octanethiol (OT) and octylammonium bromide that can passivate the defects of PEQD and effectively reduce the Stokes shift. First, the increase in the OT concentration in hybrid ligands leads to an increase in the PEQD size and a decrease in the Stokes shift. Second, OT in hybrid ligands can stabilize the PEQD solution by binding to an MA ion, which is easily degraded by atmospheric oxygen, thereby suppressing the generation of metallic Pb that serves as a defect in PEQDs. Consequently, PEQDs by hybrid ligands reduced the defects, particularly metallic Pb, leading to strong green emission with low Stokes shift with a photoluminescence quantum yield of 99.3 % and high stability under atmospheric conditions. [Display omitted] • Hybrid ligand can stabilize the perovskite quantum dot. • Hybrid ligand shows the highly luminescent perovskite quantum dot. • Hybrid ligand can control the perovskite quantum dot size and Stoke shift. • Hybrid ligand can eliminate the perovskite vacancies leading to defect. [ABSTRACT FROM AUTHOR]

One of the essential calibration procedures for the motional Stark effect (MSE) diagnostic system includes obtaining the mapping responses of the angle evaluated from the demodulation of the photoelastic-modulated raw signals in the MSE polarimeter to the incident polarized light either parallel or perpendicular to the Lorentz electric field originated from a flux surface of a tokamak plasma. This in-vessel mapping calibration procedure that is practically very time-consuming and tedious has been improved by a newly developed MSE in-vessel calibration system with the capability of remote and automatic operations for the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak. The key design has employed the concept that the polarization state is preserved along an observation line of sight once the polarizer surface, or the wave front of the polarized light, is perpendicular to the line of sight. Comparisons with previous manual calibration procedures confirm this concept is applicable practically. The new remote and automatic calibration activities performed with this new system yield unprecedented angular coverage and resolution in the mapping curves between the incident polarization angles and measured angles. The performance of the new calibration mechanism, free from various time constraints related to scheduling tokamak maintenance period, is virtually limited only by the precision of the motorized rotational stage that mounts the polarized light source on it, which is less than a hundredth of a degree. • Utilization of polarization preservation along a line of sight for system compactness. • Unprecedented angular resolutions in the MSE in-vessel mapping calibration. • Flexibility in integrating MSE in-vessel calibration with tokamak maintenance period. [ABSTRACT FROM AUTHOR]

Perovskite X-ray detectors are actively investigated because of their exceptional properties, including their significant attenuation coefficient, low defect density, excellent transport characteristics, easy growth, and high sensitivity to X-ray photons. However, perovskite-based high-energy X-ray detectors on the MeV scale are rarely explored. In this study, we investigate the optoelectronic characteristics and radiation detection capabilities of triple-cation Cs 0.05 FA 0.9 MA 0.05 PbI 3 single crystals (CSC) grown using the inverse temperature crystallization method. The CSCs with a reduced Goldschmidt tolerance factor owing to the presence of Cs and MA ions exhibit exceptional properties, including a bandgap of 1.447 eV, low dark current, and self-powered response to X-ray irradiation. The X-ray absorption rate of 36 keV exceeded 99% with a CSC thickness of 2 mm, demonstrating its strong stopping power. Moreover, the CSC detectors exhibit precise linear responses to varying X-ray doses and dose rates with R2 values close to 1 and relative standard deviation (RSD) values below 3% under all the tested conditions. In addition, the detector effectively detected high-energy X-rays of up to 15 MV with minimal variations in the RSD values. These findings highlight the potential of CSC as promising materials for high-performance X-ray detectors. • Triple-cation lead–halide perovskites for high-energy X-ray detection were studied. • CSC detector has uniform linear response to varying X-ray doses and rates. • CSC detector can detect high-energy X-rays of up to 15 MeV. • CSC demonstrated remarkable promise as excellent self-powered X-ray detectors. [ABSTRACT FROM AUTHOR]

Organic-inorganic perovskite single crystals (SCs) are considered promising semiconductors for high-sensitivity X-ray detectors because of their strong X-ray interaction, low-temperature processability, and excellent properties such as long diffusion length, low defect density, and long carrier lifetime. However, the specific pulse response of MAPbBr 3 SC-based X-ray detectors frequently exhibits a tail and over/undershoots at several conditions, which degrades the X-ray image quality; however, no detailed analysis of these characteristics has been reported thus far. For high-resolution X-ray imaging, it is necessary to obtain an ideal pulse response that is free of tails and over/undershoots. In this study, we investigated the specific X-ray responses of solution-grown MAPbBr 3 SC-based X-ray detectors under various externally applied voltages. Based on the study on charge carrier dynamics, we analyzed the origin of the tail and over/undershoots in X-ray pulse response shapes. We theoretically verified that the unideal pulse response in perovskite SC-based X-ray detectors is attributed to the defect states inherent in perovskite SCs. • X-ray responses of MAPbBr 3 single-crystal detectors with different electrodes are investigated. • The specific pulse responses of the detectors show tail and over/undershoots. • Tail and overshoots can be interpreted as de-trapping and trapping, respectively, on shallow traps. • Undershoot is caused by diffusion currents due to the internal fields and unoccupied vacancies. [ABSTRACT FROM AUTHOR]

• Single crystal based solar cells as the big new wave in perovskite photovoltaic technology. • Potential growth methods for the SC perovskite discussed thoroughly. • Surface trap management via various techniques is broadly reviewed. • Challenges and potential strategies are discussed to achieve stable and efficient SC-PSCs. The structural disorder, large grain boundaries, and significantly high defect density within polycrystalline perovskite solar cells (PC-PSCs) have raised the issue of their sustainability for an extended period. Therefore, single-crystal perovskite solar cells (SC-PSCs) have recently received significant attention in the fabrication of highly efficient and stable PSCs owing to their synergistic properties. The development of advanced SC-PSCs represents a promising pathway to fabricate highly efficient and stable perovskite-based solar cells. However, advances in the fabrication methods of SC-PSCs are needed to achieve equal or higher efficiency than that offered by the existing solar technology based on polycrystalline perovskite solar cells (PC-PSCs). Potential methods for growing SC-perovskite thin films with appropriate surface trap management must be explored to achieve an optimum efficiency closer to the Shockley-Queisser (S-Q) limit. This review highlights the potential methods for growing SC-perovskite thin films and their applications in SC-PSCs. In addition, this study also summarizes several critical factors related to SC-PSCs, including carrier dynamics, ion migration, defect densities, and stability. Our analysis also explores the possibilities of SC-PSCs for commercialization to establish a secure industrial symbiosis with circular cost-benefit analysis. This review aims to provide significant insights in the field of SC-PSCs and present the future challenges and possible solutions to render SC-PSCs as a successful futuristic photovoltaic technology. [ABSTRACT FROM AUTHOR]