Maddalena Francesco, Witkowski Marcin E, Makowski Michal, Bachiri Abdellah, Mahler Benoit, Wong Ying-Chieh, Chua Cheng Yi Eric, Lee Jia Xing, Drozdowski Winicjusz, Springham Stuart Victor, Dujardin Christophe, Birowosuto Muhammad Danang, Dang Cuong
School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
CINTRA UMI CNRS/NTU/THALES 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, 637553 Singapore.
ACS Appl Mater Interfaces. 2021 Dec 15;13(49):59450-59459. doi: 10.1021/acsami.1c16171. Epub 2021 Dec 2.
CsPbBr quantum dots (QDs) have recently gained much interest due to their excellent optical and scintillation properties and their potential for X-ray imaging applications. In this study, we blended CsPbBr QDs with resin at different QD concentrations to achieve thick films and to protect the CsPbBr QDs from environmental moisture. Then, their scintillation properties are investigated and compared to the traditional commercial scintillators, CsI:Tl microcolumns, and Gadox layers. The CsPbBr QD-resin sheets show a high light yield of up to 21 500 photons/MeV at room temperature and a relatively small variation in light yield across a wide temperature range. In addition, the CsPbBr QD-resin sheets feature a small scintillation afterglow. The CsPbBr QD-resin sheets show a negligible trap density for the concentration below 50% weight, indicating that traps might arise from the aggregation of the QDs. The CsPbBr QD-resin sheets are also very stable at low irradiation intensities and relatively stable at higher intensities, with higher CsPbBr QD concentrations being more stable. Gamma-ray-excited-time-resolved emission measurements at 662 keV showed that the CsPbBr QD-resin sheets have an average scintillation decay time between 108 and 176 ns, which are still 10 000 and 6000 times faster than CsI:Tl and Gadox, respectively. Imaging tests show that the CsPbBr QD-resin sheets have a mean transfer function of 50% at 2 lp/mm and 20% at 4 lp/mm, comparable to that of commercial Gadox layers. This feature makes CsPbBr QD-resin sheets a good candidate for the low-cost, flexible X-ray imaging screens and γ-ray applications.
CsPbBr量子点（QDs）因其优异的光学和闪烁特性以及在X射线成像应用中的潜力，近来备受关注。在本研究中，我们将CsPbBr量子点与树脂以不同的量子点浓度混合，以制备厚膜，并保护CsPbBr量子点免受环境湿气影响。然后，对其闪烁特性进行了研究，并与传统商业闪烁体CsI:Tl微柱和钆塞酸二钠层进行了比较。CsPbBr量子点-树脂片在室温下显示出高达21500光子/兆电子伏的高光产额，并且在很宽的温度范围内光产额变化相对较小。此外，CsPbBr量子点-树脂片具有较小的闪烁余辉。CsPbBr量子点-树脂片在重量浓度低于50%时显示出可忽略不计的陷阱密度，这表明陷阱可能源于量子点的聚集。CsPbBr量子点-树脂片在低辐照强度下也非常稳定，在较高强度下相对稳定，CsPbBr量子点浓度越高越稳定。在662 keV下进行的伽马射线激发时间分辨发射测量表明，CsPbBr量子点-树脂片的平均闪烁衰减时间在108到176纳秒之间，分别比CsI:Tl和钆塞酸二钠快10000倍和6000倍。成像测试表明，CsPbBr量子点-树脂片在2线对/毫米处的平均传递函数为50%，在4线对/毫米处为20%，与商业钆塞酸二钠层相当。这一特性使CsPbBr量子点-树脂片成为低成本、柔性X射线成像屏和γ射线应用的良好候选材料。
