A Study on an Organic Semiconductor-Based Indirect X-ray Detector with Cd-Free QDs for Sensitivity Improvement

High-Efficiency ZnS: Cu+, Al3+ Scintillator for X-ray Detection in a Non-Darkroom Environment

Scintillator is a key component in X-ray detectors that determine the performance of the devices. Nevertheless, due to the interference of the ambient light sources, scintillators are only operated in a darkroom environment currently. In this study, we designed a Cu⁺ and Al³⁺ co-doped ZnS scintillator (ZnS: Cu⁺, Al³⁺) that introduces donor-acceptor (D-A) pairs for X-ray detection. The prepared scintillator displayed an extremely high steady-state light yield (53,000 photons per MeV) upon X-ray irradiation, which is 5.3 times higher than that of the commercial Bi₄Ge₃O₁₂ (BGO) scintillator, making it possible in X-ray detection with the interference of ambient light. Furthermore, the prepared material was employed as a scintillator to construct an indirect X-ray detector, which performed a superior spatial resolution (≈10.0 lp/mm) as well as persistent stability under visible light interference, demonstrating the feasibility of the scintillator in practical applications. Therefore, this research presented a convenient and useful strategy to realize X-ray detection in a non-darkroom environment.

A Study on Improving the Sensitivity of Indirect X-ray Detectors by Adding Hybrid Perovskite Quantum Dots

In this paper, we demonstrate the enhancement in detection sensitivity of an indirect X-ray detector based on poly(3-hexylthiophene) (P3HT) and fullerene derivatives [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) by adding perovskite quantum dots (PeQDs). The weight ratio of P3HT and PC71BM was fixed at 1:1 (20 mg/mL in chlorobenzene), and different amounts of FAPbBr3 PeQDs of (0–3) mg were added to the P3HT:PC71BM active layer solution. The experimental results show that the detector using P3HT:PC71BM:FAPbBr3 PeQDs (1 mg) achieved a sensitivity of 2.10 mA/Gy∙cm2. To further improve the sensitivity, a ligand exchange experiment was performed on the P3HT:PC71BM:FAPbBr3 PeQDs (1 mg) detector. Under the condition of 12 h ligand exchange time, the detector with P3HT:PC71BM:FAPbBr3 PeQDs (1 mg) showed the highest sensitivity of 2.26 mA/Gy∙cm2, which was increased by 28% compared to the pristine detector with a P3HT:PC71BM active layer.

Ultrasonically Processed WSe2 Nanosheets Blended Bulk Heterojunction Active Layer for High-Performance Polymer Solar Cells and X-ray Detectors

Two-dimensional (2D) tungsten diselenide (WSe2) has attracted considerable attention in the field of photovoltaic devices owing to its excellent structure and photoelectric properties, such as ordered 2D network structure, high electrical conductivity, and high mobility. For this test, we firstly prepared different sizes (NS1-NS3) of WSe2 nanosheets (NSs) through the ultrasonication method and characterized their structures using the field emission scanning electron microscope (FE-SEM), Raman spectroscopy, and X-ray powder diffraction. Moreover, we investigated the photovoltaic performance of polymer solar cells based on 5,7-Bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione(PBDB-T):(6,6)-phenyl-C71 butyric acid methyl ester (PCBM) with different WSe2 NSs as the active layer. The fabricated PBDB-T:PCBM active layer with the addition of NS2 WSe2 NSs (1.5 wt%) exhibited an improved power conversion efficiency (PCE) of 9.2%, which is higher than the pure and NS1 and NS3 WSe2 blended active layer-encompassing devices. The improved PCE is attributed to the synergic enhancement of exciton dissociation and an improvement in the charge mobility through the modified active layer for polymer solar cells. Furthermore, the highest sensitivity of 2.97 mA/Gy·cm2 was achieved for the NS2 WSe2 NSs blended active layer detected by X-ray exposure over the pure polymer, and with the NS1 and NS2 WSe2 blended active layer. These results led to the use of transition metal dichalcogenide materials in polymer solar cells and X-ray detectors.