Zero-dimensional(0D)hybrid metal halides are under intensive investigation owing to their unique physical properties,such as the broadband emission from highly localized excitons that is promising for white-emitting l...Zero-dimensional(0D)hybrid metal halides are under intensive investigation owing to their unique physical properties,such as the broadband emission from highly localized excitons that is promising for white-emitting lighting.However,fundamental understanding of emission variations and structure–property relationships is still limited.Here,by using pressure processing,we obtain robust exciton emission in 0D(C_(9)NH_(20))_(6)Pb_(3)Br_(12) at room temperature that can survive to 80 GPa,the recorded highest value among all the hybrid metal halides.In situ experimental characterization and first-principles calculations reveal that the pressure-induced emission is mainly caused by the largely suppressed phonon-assisted nonradiative pathway.Lattice compression leads to phonon hardening,which considerably weakens the exciton–phonon interaction and thus enhances the emission.The robust emission is attributed to the unique structure of separated spring-like[Pb_(3)Br_(12)]^(6−)trimers,which leads to the outstanding stability of the optically active inorganic units.Our findings not only reveal abnormally robust emission in a 0D metal halide,but also provide new insight into the design and optimization of local structures of trimers and oligomers in lowdimensional hybrid materials.展开更多
Dehydro-Diels-Alder(DDA)reaction is a textbook reaction for preparing six-membered rings in solution but is scarcely seen in solid-state synthesis.In this work,using multiple characterization techniques,we demonstrate...Dehydro-Diels-Alder(DDA)reaction is a textbook reaction for preparing six-membered rings in solution but is scarcely seen in solid-state synthesis.In this work,using multiple characterization techniques,we demonstrate that the bowl-shaped clusters C_(18)Te_(3)Br_(4)(Bu-O)_(6) might experience a DDA reaction at room temperature and high pressure between 5.5 and 7.4 GPa.Above 17.0 GPa,it is found that the bonding conversion from the intramolecular sp^(2) to the intermolecular spa occurred,in the form of pressure-induced diamondization.The recovered samples from 20.0 and 36.1 GPa showed incomplete reversibility,while the decompression-induced graphitization of glassy carbon was observed during decompression from 46.5 GPa.The electrochemical impedance spectroscopy results indicated that the transport properties changed from grain boundary dominant to grain dominant due to the DDA reaction and the grain boundary effect disappeared as the intermolecular sp3 bonding building-up and carrier transmission channel formation above 17.0 GPa.The results in this study open a new route to construct the crystalline carbon materials with different transport properties.展开更多
基金supported by the National Nature Science Foundation of China(NSFC)(Grant Nos.U1930401 and 51527801)support from the National Science Foundation(Grant No.DMR-1709116)+2 种基金supported by the National Science Foundation–Earth Sciences(Grant No.EAR-1634415)the Department of Energy–GeoSciences(Grant No.DE-FG02-94ER14466)partially by COMPRES under NSF Cooperative Agreement No.EAR-1606856.
文摘Zero-dimensional(0D)hybrid metal halides are under intensive investigation owing to their unique physical properties,such as the broadband emission from highly localized excitons that is promising for white-emitting lighting.However,fundamental understanding of emission variations and structure–property relationships is still limited.Here,by using pressure processing,we obtain robust exciton emission in 0D(C_(9)NH_(20))_(6)Pb_(3)Br_(12) at room temperature that can survive to 80 GPa,the recorded highest value among all the hybrid metal halides.In situ experimental characterization and first-principles calculations reveal that the pressure-induced emission is mainly caused by the largely suppressed phonon-assisted nonradiative pathway.Lattice compression leads to phonon hardening,which considerably weakens the exciton–phonon interaction and thus enhances the emission.The robust emission is attributed to the unique structure of separated spring-like[Pb_(3)Br_(12)]^(6−)trimers,which leads to the outstanding stability of the optically active inorganic units.Our findings not only reveal abnormally robust emission in a 0D metal halide,but also provide new insight into the design and optimization of local structures of trimers and oligomers in lowdimensional hybrid materials.
基金This work was supported by the National Natural Science Foundation of China(Nos.52090020 and 11874076)the National Research Foundation of Korea(Nos.2016K1A4A3914691 and 2018R1DA1B070498).
文摘Dehydro-Diels-Alder(DDA)reaction is a textbook reaction for preparing six-membered rings in solution but is scarcely seen in solid-state synthesis.In this work,using multiple characterization techniques,we demonstrate that the bowl-shaped clusters C_(18)Te_(3)Br_(4)(Bu-O)_(6) might experience a DDA reaction at room temperature and high pressure between 5.5 and 7.4 GPa.Above 17.0 GPa,it is found that the bonding conversion from the intramolecular sp^(2) to the intermolecular spa occurred,in the form of pressure-induced diamondization.The recovered samples from 20.0 and 36.1 GPa showed incomplete reversibility,while the decompression-induced graphitization of glassy carbon was observed during decompression from 46.5 GPa.The electrochemical impedance spectroscopy results indicated that the transport properties changed from grain boundary dominant to grain dominant due to the DDA reaction and the grain boundary effect disappeared as the intermolecular sp3 bonding building-up and carrier transmission channel formation above 17.0 GPa.The results in this study open a new route to construct the crystalline carbon materials with different transport properties.
