Metal halide perovskites have made significant progress in X-ray detection owing to their exceptional optoelec-tronic properties.However,most of these materials suffer from toxic element lead and require for high oper...Metal halide perovskites have made significant progress in X-ray detection owing to their exceptional optoelec-tronic properties.However,most of these materials suffer from toxic element lead and require for high operating voltages.Hence,it is imperative to explore environmentally friendly perovskite crystals without external bias for X-ray detection.Herein,we strategically introduce chiral cations to synthesize a pair of lead-free chiral-polar hybrid perovskites(S-MPz)_(6)Bi_(3)I_(21)·6H_(2)O and(R-MPz)_(6)Bi_(3)I_(21)·6H_(2)O(1S and 1R,S/R-MPz=S/R-2-methylpipera-zinium),which exhibit strong circular dichroism(CD)signals with an anisotropic g-factor reaching approximately 0.017.Significantly,the chiral-polar feature gives rise to distinctive spontaneous polarization,which leads to a photovoltage of 1.1 V under X-ray illumination,endowing self-powered detection capabilities for X-ray.Further exploration of X-ray devices based on 1R single crystal(SC)demonstrates a high sensitivity of 5.2 pC Gy_(air)^(-1)cm^(-2)at zero bias.This study realizes passive X-ray detection depending on the intrinsic spontaneous polarization induced built-in electric field of chiral-polar perovskite,providing an effective approach to the chemical design of desired materials for high-performance"green"self-powered radiation detection.展开更多
A double-well potential model is proposed for the pionic deuterium that enables to calculate the energy split, the potential barrier height and estimate the pion tetrahedron edge length. We propose that pion tetrahedr...A double-well potential model is proposed for the pionic deuterium that enables to calculate the energy split, the potential barrier height and estimate the pion tetrahedron edge length. We propose that pion tetrahedrons, π<sup>Td</sup> = u<sub>d</sub>~</sup>dũ, play a central role in the Yukawa interaction by enabling quark exchange reactions between protons and neutrons by tunneling through a potential barrier. A vacuum polarization Feynman diagram is proposed for the π<sup>Td</sup> having chains of fermion loops for the two valence quarks and anti-quarks connected by gluons. With a higher order vacuum polarization diagram, the d and u quark loops are interleaved and the chiral symmetry is broken dynamically. The proposed π<sup>Td</sup> vacuum polarization integral does not diverge in both the IR and UV limits and vanishes in the limit of an infinite pion tetrahedron condensate. We propose a new Delbruck scattering Feynman diagram that includes d and u quark and anti-quark interleaved loops. We further propose that conversion of gravitons to photons may occur via quark and anti-quark loops that describe the pion tetrahedrons dynamics in the vacuum and may also transfer gravitational waves.展开更多
通过紫外光照射后,在光引发剂作用下预聚物发生自由基聚合,制备了含有手性掺杂的聚合物分散液晶.用偏光显微镜观察小分子液晶的粒径大小及其在聚合物网络中的分布形态,通过三官能团预聚物三羟甲基丙烷三丙烯酸酯的快速聚合获得了微米级...通过紫外光照射后,在光引发剂作用下预聚物发生自由基聚合,制备了含有手性掺杂的聚合物分散液晶.用偏光显微镜观察小分子液晶的粒径大小及其在聚合物网络中的分布形态,通过三官能团预聚物三羟甲基丙烷三丙烯酸酯的快速聚合获得了微米级液晶微滴,用旋光仪(PerkinEl mer Model 341 Polari meter)测量温度作用下手性聚合物分散液晶的旋光性变化,结果与de Vries理论相一致.手性掺杂的聚合物分散液晶的旋光性、选择反射等独特的光学性能被广泛应用于滤波片、光栅、反射显示等方面.展开更多
基金supported by the National Natural Science Foundation of China(22322506,22175177,22193042,22125110,22122507,21921001 and U21A2069)the Natural Science Foundation of Fujian Province(2023J06052)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024).
文摘Metal halide perovskites have made significant progress in X-ray detection owing to their exceptional optoelec-tronic properties.However,most of these materials suffer from toxic element lead and require for high operating voltages.Hence,it is imperative to explore environmentally friendly perovskite crystals without external bias for X-ray detection.Herein,we strategically introduce chiral cations to synthesize a pair of lead-free chiral-polar hybrid perovskites(S-MPz)_(6)Bi_(3)I_(21)·6H_(2)O and(R-MPz)_(6)Bi_(3)I_(21)·6H_(2)O(1S and 1R,S/R-MPz=S/R-2-methylpipera-zinium),which exhibit strong circular dichroism(CD)signals with an anisotropic g-factor reaching approximately 0.017.Significantly,the chiral-polar feature gives rise to distinctive spontaneous polarization,which leads to a photovoltage of 1.1 V under X-ray illumination,endowing self-powered detection capabilities for X-ray.Further exploration of X-ray devices based on 1R single crystal(SC)demonstrates a high sensitivity of 5.2 pC Gy_(air)^(-1)cm^(-2)at zero bias.This study realizes passive X-ray detection depending on the intrinsic spontaneous polarization induced built-in electric field of chiral-polar perovskite,providing an effective approach to the chemical design of desired materials for high-performance"green"self-powered radiation detection.
基金Supported by the National Key Research and Development Program of China(2022YFA1404602)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0580000)+4 种基金the Key Deployment Projects of the Chinese Academy of Sciences(ZDRW-XH-2021-7-1)the National Natural Science Foundation of China(61975223,61991442,62305362,62075230)the Program of Shanghai Academic/Technology Research Leader(22XD1424400)the Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Natural Science Foundation of Shanghai(19ZR1465400)。
文摘A double-well potential model is proposed for the pionic deuterium that enables to calculate the energy split, the potential barrier height and estimate the pion tetrahedron edge length. We propose that pion tetrahedrons, π<sup>Td</sup> = u<sub>d</sub>~</sup>dũ, play a central role in the Yukawa interaction by enabling quark exchange reactions between protons and neutrons by tunneling through a potential barrier. A vacuum polarization Feynman diagram is proposed for the π<sup>Td</sup> having chains of fermion loops for the two valence quarks and anti-quarks connected by gluons. With a higher order vacuum polarization diagram, the d and u quark loops are interleaved and the chiral symmetry is broken dynamically. The proposed π<sup>Td</sup> vacuum polarization integral does not diverge in both the IR and UV limits and vanishes in the limit of an infinite pion tetrahedron condensate. We propose a new Delbruck scattering Feynman diagram that includes d and u quark and anti-quark interleaved loops. We further propose that conversion of gravitons to photons may occur via quark and anti-quark loops that describe the pion tetrahedrons dynamics in the vacuum and may also transfer gravitational waves.
文摘通过紫外光照射后,在光引发剂作用下预聚物发生自由基聚合,制备了含有手性掺杂的聚合物分散液晶.用偏光显微镜观察小分子液晶的粒径大小及其在聚合物网络中的分布形态,通过三官能团预聚物三羟甲基丙烷三丙烯酸酯的快速聚合获得了微米级液晶微滴,用旋光仪(PerkinEl mer Model 341 Polari meter)测量温度作用下手性聚合物分散液晶的旋光性变化,结果与de Vries理论相一致.手性掺杂的聚合物分散液晶的旋光性、选择反射等独特的光学性能被广泛应用于滤波片、光栅、反射显示等方面.
