Spatial resolution is an important criterion to evaluate the performance of a scintillation screen for X-ray imaging.Perovskite-based X-ray screen,usually made of powders or polycrystalline films,suffers from low spat...Spatial resolution is an important criterion to evaluate the performance of a scintillation screen for X-ray imaging.Perovskite-based X-ray screen,usually made of powders or polycrystalline films,suffers from low spatial resolution(~200μm)due to the large thickness of scintillation layer despite of their compelling sensitivity to X-ray dose.In this work,a concentrated colloid of CsPbBr_(3)nanosheets was synthesized via a co-precipitation method at ambient condition.By drop casting,smooth scintillation screens of varied thickness were formed through self-assembly,which exhibited both high internal and external photoluminescence quantum yield(PL QY)(84.5%and 75.1%,respectively).The screen-based X-ray detector showed a high sensitivity down to 27 nGy/s,two orders of magnitude lower than the regular dose for medical diagnostics.Importantly,the screen of optimal thickness of 15μm showcased an unprecedented spatial resolution(26μm)when used for X-ray radiography,representing one order of magnitude improvement in perovskite community.展开更多
基金the National Natural Science Foundation of China(No.21805111)Natural Science Foundation of Shandong Province(No.ZR2020YQ12)Taishan Scholar Project of Shandong Province(No.tsqn201812082).
文摘Spatial resolution is an important criterion to evaluate the performance of a scintillation screen for X-ray imaging.Perovskite-based X-ray screen,usually made of powders or polycrystalline films,suffers from low spatial resolution(~200μm)due to the large thickness of scintillation layer despite of their compelling sensitivity to X-ray dose.In this work,a concentrated colloid of CsPbBr_(3)nanosheets was synthesized via a co-precipitation method at ambient condition.By drop casting,smooth scintillation screens of varied thickness were formed through self-assembly,which exhibited both high internal and external photoluminescence quantum yield(PL QY)(84.5%and 75.1%,respectively).The screen-based X-ray detector showed a high sensitivity down to 27 nGy/s,two orders of magnitude lower than the regular dose for medical diagnostics.Importantly,the screen of optimal thickness of 15μm showcased an unprecedented spatial resolution(26μm)when used for X-ray radiography,representing one order of magnitude improvement in perovskite community.
