Atomically thin two-dimensional(2D)bismuth oxychalcogenides(Bi_(2)O_(2)X,X=S,Se,Te)have recently attracted extensive attention in the material research community due to their unique structure,outstanding long-term amb...Atomically thin two-dimensional(2D)bismuth oxychalcogenides(Bi_(2)O_(2)X,X=S,Se,Te)have recently attracted extensive attention in the material research community due to their unique structure,outstanding long-term ambient stability,and high carrier mobility,which enable them as promising candidates for high-performance electronic and optoelectronic applications.Herein,we present a comprehensive review on the recent advances of 2D bismuth oxychalcogenides research.We start with an introduction of their fundamental properties including crystal structure and electronic band structure.Next,we summarize the common techniques for synthesizing these 2D structures with high crystallinity and large lateral size.Furthermore,we elaborate on their device applications including transistors,artificial synapses,optical switch and photodetectors.The last but not the least,we summarize the existing challenges and prospects for this emerging 2D bismuth oxychalcogenides field.展开更多
A new layered Cu-based oxychalcogenide Ba_3Fe_2O_5Cu_2S_2 has been synthesized and its magnetic and electronic properties were revealed. Ba_3Fe_2O_5Cu_2S_2 is built up by alternatively stacking [Cu_2S_2]^（2-） layers...A new layered Cu-based oxychalcogenide Ba_3Fe_2O_5Cu_2S_2 has been synthesized and its magnetic and electronic properties were revealed. Ba_3Fe_2O_5Cu_2S_2 is built up by alternatively stacking [Cu_2S_2]^（2-） layers and iron perovskite oxide[（FeO_2）（BaO）（FeO_2）]^（2-）layers along the c axis that are separated by barium ions with Fe^（3＋） fivefold coordinated by a square-pyramidal arrangement of oxygen. From the bond valence arguments, we inferred that in layered CuC h-based（Ch =S, Se, Te） compounds the ＋3 cation in perovskite oxide sheet prefers a square pyramidal site, while the lower valence cation prefers the square planar sites. The studies on susceptibility, transport, and optical reflectivity indicate that Ba_3Fe_2O_5Cu_2S_2 is an antiferromagnetic semiconductor with a Ne′el temperature of 121 K and an optical bandgap of 1.03 eV. The measurement of heat capacity from 10 K to room temperature shows no anomaly at 121 K. The Debye temperature is determined to be 113 K. Theoretical calculations indicate that the conduction band minimum is predominantly contributed by O 2p and 3 d states of Fe ions that antiferromagnetically arranged in FeO_2 layers. The Fe 3d states are located at lower energy and result in a narrow bandgap in comparison with that of the isostructural Sr_3Sc_2O_5Cu_2S_2.展开更多
Birefringent crystals are crucial for manipulating light's phase and polarization,making them vital components in various optical devices.Traditionally,strategies for designing high-performance birefringent crysta...Birefringent crystals are crucial for manipulating light's phase and polarization,making them vital components in various optical devices.Traditionally,strategies for designing high-performance birefringent crystals have focused on modifying the parent structure.However,there are limited examples demonstrating how changing functional groups can effectively enhance birefringence(Δn),as such changes often significantly alter the crystal structure.In this study,we propose a“functional group implantation”strategy aiming at significantly improving birefringent performance within the chalcogenide system.This involves replacing the isotropic[S]^(2-)ions with anisotropicπ-conjugated[CO_(3)]^(2-)groups.We validated this approach through comprehensive comparisons between the chalcogenide[Ba_(3)S][GeS_(4)]and oxychalcogenide[Ba_(3)CO_(3)][MS_(4)](M=Ge and Sn),both of which adopt the same space group and feature the same arrangements of functional groups.Experimental characterization and theoretical calculations confirm that the[CO_(3)]^(2-)groups exhibit significantly greater polarization anisotropy than the[S]^(2-)groups.This difference leads to a marked increase inΔn in[Ba_(3)CO_(3)][MS_(4)](ranging from 0.088 to 0.112 at 546 nm)compared to[Ba_(3)S][GeS_(4)](0.021 at 546 nm).This finding not only broadens the structural chemistry ofπ-conjugated chalcogenides but also illustrates the potential of functional group implantation for designing infrared birefringent crystals with enhanced optical anisotropy.展开更多
基金Fundamental Research Funds for the Central Universities,Grant/Award Number:2019kfyXMBZ018Hubei Provincial Nature Science Foundation of China,Grant/Award Number:2019CFA002National Nature Science Foundation of China,Grant/Award Numbers:21825103,51727809。
文摘Atomically thin two-dimensional(2D)bismuth oxychalcogenides(Bi_(2)O_(2)X,X=S,Se,Te)have recently attracted extensive attention in the material research community due to their unique structure,outstanding long-term ambient stability,and high carrier mobility,which enable them as promising candidates for high-performance electronic and optoelectronic applications.Herein,we present a comprehensive review on the recent advances of 2D bismuth oxychalcogenides research.We start with an introduction of their fundamental properties including crystal structure and electronic band structure.Next,we summarize the common techniques for synthesizing these 2D structures with high crystallinity and large lateral size.Furthermore,we elaborate on their device applications including transistors,artificial synapses,optical switch and photodetectors.The last but not the least,we summarize the existing challenges and prospects for this emerging 2D bismuth oxychalcogenides field.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51472266,51202286,and 91422303)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB07020100)the ICDD
文摘A new layered Cu-based oxychalcogenide Ba_3Fe_2O_5Cu_2S_2 has been synthesized and its magnetic and electronic properties were revealed. Ba_3Fe_2O_5Cu_2S_2 is built up by alternatively stacking [Cu_2S_2]^（2-） layers and iron perovskite oxide[（FeO_2）（BaO）（FeO_2）]^（2-）layers along the c axis that are separated by barium ions with Fe^（3＋） fivefold coordinated by a square-pyramidal arrangement of oxygen. From the bond valence arguments, we inferred that in layered CuC h-based（Ch =S, Se, Te） compounds the ＋3 cation in perovskite oxide sheet prefers a square pyramidal site, while the lower valence cation prefers the square planar sites. The studies on susceptibility, transport, and optical reflectivity indicate that Ba_3Fe_2O_5Cu_2S_2 is an antiferromagnetic semiconductor with a Ne′el temperature of 121 K and an optical bandgap of 1.03 eV. The measurement of heat capacity from 10 K to room temperature shows no anomaly at 121 K. The Debye temperature is determined to be 113 K. Theoretical calculations indicate that the conduction band minimum is predominantly contributed by O 2p and 3 d states of Fe ions that antiferromagnetically arranged in FeO_2 layers. The Fe 3d states are located at lower energy and result in a narrow bandgap in comparison with that of the isostructural Sr_3Sc_2O_5Cu_2S_2.
基金supported by the National Natural Science Foundation of China(22175175 and 22273081)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR118)the Natural Science Foundation of Fujian Province(2022L3092 and 2023H0041).
文摘Birefringent crystals are crucial for manipulating light's phase and polarization,making them vital components in various optical devices.Traditionally,strategies for designing high-performance birefringent crystals have focused on modifying the parent structure.However,there are limited examples demonstrating how changing functional groups can effectively enhance birefringence(Δn),as such changes often significantly alter the crystal structure.In this study,we propose a“functional group implantation”strategy aiming at significantly improving birefringent performance within the chalcogenide system.This involves replacing the isotropic[S]^(2-)ions with anisotropicπ-conjugated[CO_(3)]^(2-)groups.We validated this approach through comprehensive comparisons between the chalcogenide[Ba_(3)S][GeS_(4)]and oxychalcogenide[Ba_(3)CO_(3)][MS_(4)](M=Ge and Sn),both of which adopt the same space group and feature the same arrangements of functional groups.Experimental characterization and theoretical calculations confirm that the[CO_(3)]^(2-)groups exhibit significantly greater polarization anisotropy than the[S]^(2-)groups.This difference leads to a marked increase inΔn in[Ba_(3)CO_(3)][MS_(4)](ranging from 0.088 to 0.112 at 546 nm)compared to[Ba_(3)S][GeS_(4)](0.021 at 546 nm).This finding not only broadens the structural chemistry ofπ-conjugated chalcogenides but also illustrates the potential of functional group implantation for designing infrared birefringent crystals with enhanced optical anisotropy.
