The layered heterometallic halide perovskites, as a newly explored material, have attracted great scientific attention. As one of the representatives of perovskite, lead-free or lead-substituted perovskite materials a...The layered heterometallic halide perovskites, as a newly explored material, have attracted great scientific attention. As one of the representatives of perovskite, lead-free or lead-substituted perovskite materials are widely applied in photovoltaic, sensors, catalysis, detectors and other fields. Therefore, it is urgent to carry out more systematic exploration and expand applicable preresearch, so as to make more interesting discoveries in this new hot spot. As an interesting candidate, heterometallic compounds will introduce more structural adjustability and novel physical properties, which is the main feature to be selected as the research hotspot. Here, we reported a lead-free bilayer heterometallic Ruddlesden-Popper(RP) type perovskite, [(MACH)_(2)CsAgBiBr_(7)](MACH = cyclohexanemethylamine), which possesses a reversible phase transition at 379.6 K/375.1 K during heating-cooling cycle. Besides, it exhibits reddish-brown light emission under 365 nm, meanwhile, CIE chromaticity coordinate is(0.32, 0.45) on the yellow side and correlated color temperature is about 6000 K. Moreover, both the experimental data and theoretical calculation results suggest that [(MACH)_(2)CsAgBiBr_(7)] shows indirect semiconducting characteristics. In summary, this work will inspire the design of lead-free heterometallic perovskite materials for the application of sensors and light-emitting diodes(LEDs) fields.展开更多
To explore the lead-free key scientific issue in perovskite, double perovskite based on Ag Bi and Cu Bi was naturally selected as a competitive candidate due to its fascinating functional features, such as self-powere...To explore the lead-free key scientific issue in perovskite, double perovskite based on Ag Bi and Cu Bi was naturally selected as a competitive candidate due to its fascinating functional features, such as self-powered circularly polarized light detection, X-ray detection, photoluminescence and so on. However, the most challenging point is to simulate the structure and function of traditional lead-based perovskite in new double perovskite. At the same time, there are few suitable double perovskite systems with optical and electrical potential. The above two points greatly limit the competitiveness of double perovskite. In order to solve this problem, firstly, by analyzing and comparing previous studies,we used 2,2-dimethylpropan-1-aminium(abbreviated as 2,2-DPA) as the organic template to assemble materials. Solid-to-solid phase transition materials(2,2-DPA)3Bi2I91 and(2,2-DPA)3Pb2I72 were constructed. Along the path of lead-free and two-dimensional maintenance, we successfully synthesized(2,2-DPA)4AgBiI8.H_(2)O 3 and(2,2-DPA)_(4)CuBiI8.H_(2)O 4. As two typical semiconductors, 3 and 4 with narrower optical band gaps of 1.98 and 1.76 e V show obvious photo-response when the xenon lamp with intensity of 20 m W/cm^(2)is on or off, implying that they may be applied to light-harvesting and light-detecting devices. By referring to the phase transition mechanism of 1 and 2, 3 may be caused by ordered-disordered transition of the organic part, which was proven to be the first solid-to-solid phase transition material with <100>-oriented layered double perovskites with n = 1 by systematic characterization methods after dehydration for all we know. We believed that this work can provide meaningful guidance for the development of lead-free double perovskites.展开更多
Material stability is always the key factor for applied materials especially the working environment that requires higher temperature sensitivity or temperature fluctuation range.In which,the stimulus-response perovsk...Material stability is always the key factor for applied materials especially the working environment that requires higher temperature sensitivity or temperature fluctuation range.In which,the stimulus-response perovskite materials are just sensitive to stability to ensure the accuracy and stability of the signals,in the applied devices of batteries and memory storage devices and so on.However,it is still a tremendous challenge to improve the stability of perovskite materials,and maintain reliability in the devices.Here,a novel ABX_(2)X'_(1)(X-site doping in an ABX_(3))compound[CEMP]-[CdBr_(2)(SCN)](1,CEMP=1-(2-chloro-ethyl)-1-methyl-piperidine)with remarkable high-temperature reversible dielectric switching behavior was proposed.The strategy of[SCN]^(−)doping in perovskite for improving the stability was successfully achieved.Meanwhile,the steric hindrance is increased while the energy barrier is also increased by replacing hydrogen with flexible groups,which leads to a high-temperature reversible phase transition.The new finding provides a new direction to enrich new applications and design ideas of perovskite materials.Especially the X-site strategy of doping or substitution in the ABX_(3),it will promote ingenious and perfect experimental results in material synthesis and performance improvement by chemistry disciplines.展开更多
Stimulus re s ponsive materials can provide a variety of desirable properties in one equipment unit,such as optoelectronic devices,data communications,actuators,memories,sensors and capacitors.However,it remains a lar...Stimulus re s ponsive materials can provide a variety of desirable properties in one equipment unit,such as optoelectronic devices,data communications,actuators,memories,sensors and capacitors.However,it remains a large challenge to design such stimulus responsive materials,especially functional materials having both dielectric switch and second harmonic generation(SHG).Here,a new stimuli-responsive switchable material [(CH_(3))_(3)N(CH_(2))_(2)Cl]_(2)]Mn(SCN)_(4)(H_(2)O)_(2)] was discovered as a potential secondharmonic generation(SHG) dielectric switch.It is worth noting that it has SHG characteristics before and after undergoing reversible high-temperature phase transitions.In this work,we successfully refined the tetramethylammonium cation to obtain a quasi-spherical cation,which is tetramethylchloroethylamine(TMCEM) cation.By substituting H with a halogen,the increased steric hindrance of the molecular makes energy barrier increased,resulting in the reversible high-temperature phase transition.At the same time,the interactions of quasi-spherical cations and [Mn(SCN)_(4)(H_(2)O)_(2)]^(2-) anions affect a noncentrosymmetric structure to induce the SHG effect.These findings provide a new approach to design novel functional switch materials.展开更多
Organic–inorganic hybrid perovskites(OIHPs)have been a hot research topic due to their advanced structural and functional features that cover almost all the research fields of intelligent materials including ferroele...Organic–inorganic hybrid perovskites(OIHPs)have been a hot research topic due to their advanced structural and functional features that cover almost all the research fields of intelligent materials including ferroelectric,photovoltaic,fluorescent,and dielectric.However,the development of the construction of an OIHP ferroelastic semiconductor with optical-electrical response has been a huge challenge and infrequently reported.In this work,a rare and interesting hybrid perovskite ferroelastic semiconductor,[BFDA]PbBr_(3)(BFDA=benzyl-(2-fluoro-ethyl)-dimethyl-ammonium),was synthesized,which benefits from the structural advantage of a long tail BFDA to be balanced by the suitable inorganic framework.[BFDA]PbBr_(3) shows a high-temperature ferroelastic phase transition at 365 K and a direct band gap of 3.33 eV.In addition,it can emit charming orange-pink light under a 365 nm UV lamp.To combine this with the ferroelastic,optical,and dielectric properties,[BFDA]PbBr_(3) can be identified as a very rarely reported ferroelastic semiconductor.The above-mentioned synthesis strategy is also helpful for the enrichment and development of the hybrid perovskite family.展开更多
基金supported by the National Natural Science Foundation of China (No. 21991141)Zhejiang Normal University。
文摘The layered heterometallic halide perovskites, as a newly explored material, have attracted great scientific attention. As one of the representatives of perovskite, lead-free or lead-substituted perovskite materials are widely applied in photovoltaic, sensors, catalysis, detectors and other fields. Therefore, it is urgent to carry out more systematic exploration and expand applicable preresearch, so as to make more interesting discoveries in this new hot spot. As an interesting candidate, heterometallic compounds will introduce more structural adjustability and novel physical properties, which is the main feature to be selected as the research hotspot. Here, we reported a lead-free bilayer heterometallic Ruddlesden-Popper(RP) type perovskite, [(MACH)_(2)CsAgBiBr_(7)](MACH = cyclohexanemethylamine), which possesses a reversible phase transition at 379.6 K/375.1 K during heating-cooling cycle. Besides, it exhibits reddish-brown light emission under 365 nm, meanwhile, CIE chromaticity coordinate is(0.32, 0.45) on the yellow side and correlated color temperature is about 6000 K. Moreover, both the experimental data and theoretical calculation results suggest that [(MACH)_(2)CsAgBiBr_(7)] shows indirect semiconducting characteristics. In summary, this work will inspire the design of lead-free heterometallic perovskite materials for the application of sensors and light-emitting diodes(LEDs) fields.
基金financially supported by the National Natural Science Foundation of China (No. 21991141)。
文摘To explore the lead-free key scientific issue in perovskite, double perovskite based on Ag Bi and Cu Bi was naturally selected as a competitive candidate due to its fascinating functional features, such as self-powered circularly polarized light detection, X-ray detection, photoluminescence and so on. However, the most challenging point is to simulate the structure and function of traditional lead-based perovskite in new double perovskite. At the same time, there are few suitable double perovskite systems with optical and electrical potential. The above two points greatly limit the competitiveness of double perovskite. In order to solve this problem, firstly, by analyzing and comparing previous studies,we used 2,2-dimethylpropan-1-aminium(abbreviated as 2,2-DPA) as the organic template to assemble materials. Solid-to-solid phase transition materials(2,2-DPA)3Bi2I91 and(2,2-DPA)3Pb2I72 were constructed. Along the path of lead-free and two-dimensional maintenance, we successfully synthesized(2,2-DPA)4AgBiI8.H_(2)O 3 and(2,2-DPA)_(4)CuBiI8.H_(2)O 4. As two typical semiconductors, 3 and 4 with narrower optical band gaps of 1.98 and 1.76 e V show obvious photo-response when the xenon lamp with intensity of 20 m W/cm^(2)is on or off, implying that they may be applied to light-harvesting and light-detecting devices. By referring to the phase transition mechanism of 1 and 2, 3 may be caused by ordered-disordered transition of the organic part, which was proven to be the first solid-to-solid phase transition material with <100>-oriented layered double perovskites with n = 1 by systematic characterization methods after dehydration for all we know. We believed that this work can provide meaningful guidance for the development of lead-free double perovskites.
基金supported by the National Natural Science Foundation of China(No.21991141)Natural Science Foundation of Zhejiang Province(No.LZ20B010001)Zhejiang Normal University for financial support.
文摘Material stability is always the key factor for applied materials especially the working environment that requires higher temperature sensitivity or temperature fluctuation range.In which,the stimulus-response perovskite materials are just sensitive to stability to ensure the accuracy and stability of the signals,in the applied devices of batteries and memory storage devices and so on.However,it is still a tremendous challenge to improve the stability of perovskite materials,and maintain reliability in the devices.Here,a novel ABX_(2)X'_(1)(X-site doping in an ABX_(3))compound[CEMP]-[CdBr_(2)(SCN)](1,CEMP=1-(2-chloro-ethyl)-1-methyl-piperidine)with remarkable high-temperature reversible dielectric switching behavior was proposed.The strategy of[SCN]^(−)doping in perovskite for improving the stability was successfully achieved.Meanwhile,the steric hindrance is increased while the energy barrier is also increased by replacing hydrogen with flexible groups,which leads to a high-temperature reversible phase transition.The new finding provides a new direction to enrich new applications and design ideas of perovskite materials.Especially the X-site strategy of doping or substitution in the ABX_(3),it will promote ingenious and perfect experimental results in material synthesis and performance improvement by chemistry disciplines.
基金supported by the National Natural Science Foundation of China(Nos.21673038,21771037,21805033)Natural Science Foundation of Jiangsu Province(JSNSF,No.BK20170659)。
文摘Stimulus re s ponsive materials can provide a variety of desirable properties in one equipment unit,such as optoelectronic devices,data communications,actuators,memories,sensors and capacitors.However,it remains a large challenge to design such stimulus responsive materials,especially functional materials having both dielectric switch and second harmonic generation(SHG).Here,a new stimuli-responsive switchable material [(CH_(3))_(3)N(CH_(2))_(2)Cl]_(2)]Mn(SCN)_(4)(H_(2)O)_(2)] was discovered as a potential secondharmonic generation(SHG) dielectric switch.It is worth noting that it has SHG characteristics before and after undergoing reversible high-temperature phase transitions.In this work,we successfully refined the tetramethylammonium cation to obtain a quasi-spherical cation,which is tetramethylchloroethylamine(TMCEM) cation.By substituting H with a halogen,the increased steric hindrance of the molecular makes energy barrier increased,resulting in the reversible high-temperature phase transition.At the same time,the interactions of quasi-spherical cations and [Mn(SCN)_(4)(H_(2)O)_(2)]^(2-) anions affect a noncentrosymmetric structure to induce the SHG effect.These findings provide a new approach to design novel functional switch materials.
基金financially supported by the National Natural Science Foundation of China(grant no.21991141)the Science Foundation of Zhejiang Province(no.LZ20B010001)Zhejiang Normal University.
文摘Organic–inorganic hybrid perovskites(OIHPs)have been a hot research topic due to their advanced structural and functional features that cover almost all the research fields of intelligent materials including ferroelectric,photovoltaic,fluorescent,and dielectric.However,the development of the construction of an OIHP ferroelastic semiconductor with optical-electrical response has been a huge challenge and infrequently reported.In this work,a rare and interesting hybrid perovskite ferroelastic semiconductor,[BFDA]PbBr_(3)(BFDA=benzyl-(2-fluoro-ethyl)-dimethyl-ammonium),was synthesized,which benefits from the structural advantage of a long tail BFDA to be balanced by the suitable inorganic framework.[BFDA]PbBr_(3) shows a high-temperature ferroelastic phase transition at 365 K and a direct band gap of 3.33 eV.In addition,it can emit charming orange-pink light under a 365 nm UV lamp.To combine this with the ferroelastic,optical,and dielectric properties,[BFDA]PbBr_(3) can be identified as a very rarely reported ferroelastic semiconductor.The above-mentioned synthesis strategy is also helpful for the enrichment and development of the hybrid perovskite family.