The emergence of inverted perovskite solar cells(PSCs) has attached great attention derived from the potential in improving stability. Charge transporting layer, especially hole transporting layer is crucial for effic...The emergence of inverted perovskite solar cells(PSCs) has attached great attention derived from the potential in improving stability. Charge transporting layer, especially hole transporting layer is crucial for efficient inverted PSCs. Organic materials were used as hole transporting layer previously. Recently, more and more inorganic hole transporting materials have been deployed for further improving the device stability. Nickel oxide(NiOx) as p-type metal oxide, owning high charge mobility and intrinsic stability,has been widely adopted in inverted PSCs. High performance over 20% efficiency has been achieved on NiOx base inverted PSCs. Herein, we have summarized recent progresses and strategies on the NiOx based PSCs, including the synthesis or deposition methods of NiOx, doping and surface modification of NiOx for efficient and stable PSCs. Finally, we will discuss current challenges of utilizing NiOx HTLs in PSCs and attempt to give probable solutions to make further development in efficient as well as stable NiOx based PSCs.展开更多
微/纳尺度压力传感器可以检测来自外部环境的压力,分析所施加力的位置,大小和方向.这种压力传感器在电子屏幕、电子皮肤、运动监测、人工触觉系统等多个领域都有很高的应用需求.本文组装了一种可实现二维映射,基于图案化铌酸钾钠纳米棒...微/纳尺度压力传感器可以检测来自外部环境的压力,分析所施加力的位置,大小和方向.这种压力传感器在电子屏幕、电子皮肤、运动监测、人工触觉系统等多个领域都有很高的应用需求.本文组装了一种可实现二维映射,基于图案化铌酸钾钠纳米棒阵列的压力传感器矩阵.水热合成的正交相铌酸钾钠纳米棒具有优异的柔性和弹性,同时具有较高的压电性能.因此在组装的压力传感器矩阵中,单个单元尺寸低至200μm,灵敏度可达0.20 V N^(-1),检测限低至20 g,且器件的稳定性高.空间分离的传感器单元能有效避免交叉干扰,使器件能准确地实现自驱动压力成像,精确地分析外部压力刺激.展开更多
Pure and noble metal(Pt,Pd,and Au)doped TiO_(2)nanoceramics have been prepared from TiO_(2)nanoparticles through traditional pressing and sintering.For those samples sintered at 550℃,a typical premature sintering occ...Pure and noble metal(Pt,Pd,and Au)doped TiO_(2)nanoceramics have been prepared from TiO_(2)nanoparticles through traditional pressing and sintering.For those samples sintered at 550℃,a typical premature sintering occurred,which led to the formation of a highly porous microstructure with a Brunauer-Emmett-Teller(BET)specific surface area of 23 m^(2)/g.At room temperature,only Pt-doped samples showed obvious response to hydrogen,with sensitivities as high as~500 for 1000 ppm H_(2)in N_(2);at 300℃,all samples showed obvious responses to CO,while the responses of noble metal doped samples were much higher than that of the undoped ones.The mechanism for the observed sensing capabilities has been discussed,in which the catalytic effect of Pt for hydrogen is believed responsible for the room-temperature hydrogen sensing capabilities,and the absence of glass frit as commonly used in commercial thick-film metal oxide gas sensors is related to the high sensitivities.It is proposed that much attention should be paid to metal oxide porous nanoceramics in developing gas sensors with high sensitivities and low working temperatures.展开更多
Lead-free Na0.5Bi0.5TiO 3（NBT） nanofibers with the perovskite structure were prepared by the electrospinning method.The nanofibers were about 200-300 nm in diameter and up to several hundred microns in length.The cr...Lead-free Na0.5Bi0.5TiO 3（NBT） nanofibers with the perovskite structure were prepared by the electrospinning method.The nanofibers were about 200-300 nm in diameter and up to several hundred microns in length.The crystal structures and morphologies of the nanofibers were characterized by X-ray diffraction（XRD）,Raman spectroscopy,scanning electron microscopy（SEM）,and transmission electron microscopy（TEM）.The effective piezoelectric property of individual NBT nanofiber was examined by piezoresponse force microscopy（PFM）.The NBT nanofibers crystallized in pure perovskite phase after annealing above 700℃in air and comprised a great number of fine particles with size of 60-80 nm.In addition,the electromechanical energy conversion models for NBT nanofibers were built and demonstrated high voltage output as high as several millivolts.Such a result qualifies NBT nanofibers as a promising candidate for leadfree electromechanical conversion devices.展开更多
Developing an understanding of the physics underlying vibrational phonon modes,which are strongly related to thermal transport,has attracted significant research interest.Herein,we report the successful synthesis of b...Developing an understanding of the physics underlying vibrational phonon modes,which are strongly related to thermal transport,has attracted significant research interest.Herein,we report the successful synthesis of bulk SbCrSe_(3)single crystal and its thermal transport property over the temperature range from 2 to 300 K.Using angle-resolved polarized Raman spectroscopy(ARPRS)and group theory calculation,the vibrational symmetry of each observed Raman mode in the cleaved(001)crystal plane of SbCrSe_(3)is identified for the first time,and then further verified through firstprinciples calculations.The ARPRS results of some Raman modes(e.g.,Ag2~64 cm-1 and Ag 7~185 cm-1)can be adopted to determine the crystalline orientation.More importantly,the temperature dependence of the lattice thermal conductivity(κL)is revealed to be more accurately depicted by the three-phonon scattering processes throughout the measured temperature range,substantiated by in-situ Raman spectroscopy analysis and the model-predictedκL.These results reveal the fundamental physics of thermal transport for SbCrSe_(3)from a completely new perspective and should thus ignite research interest in the thermal properties of other lowdimensional materials using the same strategy.展开更多
The electronic structure and ferroelectric mechanism of trichloroacetamide were studied using first principles calculations and density functional theory within the generalized gradient approximation.Using both Bader ...The electronic structure and ferroelectric mechanism of trichloroacetamide were studied using first principles calculations and density functional theory within the generalized gradient approximation.Using both Bader charge and electron deformation density,large molecular spontaneous polarization is found to originate from the charge transfer cause by the strong“push-pull”effect of electron-releasing interacting with electron-withdrawing groups.The intermolecular hydrogen bonds,Ne-H…O,produce dipole moments in adjacent molecules to be aligned with each other.They also reduce the potential energy of the molecular chain threaded by hydrogen bonds.Due to the symmetric crystalline properties,however,the polarization of trichloroacetamide is mostly compensated and therefore small.Using the Berry Phase method,the spontaneous polarization of trichloroacetamide was simulated,and good agreement with the experimental values was found.Considering the polarization characteristics of trichloroacetamide,we constructed a one-dimensional ferroelectric Hamiltonian model to calculate the ferroelectric properties of TCAA.Using the Hamiltonian model,the thermal properties and ferroelectricity of trichloroacetamide were studied using the Monte Carlo method,and the Tc value was calculated.展开更多
Potassium sodium niobate(KNN)-based nanofibers could combine piezoelectric properties with exceptional flexibility and biocompatibility,making them highly promising for flexible sensors in electronic skin and wearable...Potassium sodium niobate(KNN)-based nanofibers could combine piezoelectric properties with exceptional flexibility and biocompatibility,making them highly promising for flexible sensors in electronic skin and wearable applications.However,the suboptimal piezoelectric performance limits their sensitivity in detecting minute human body motions,such as blinking and eye movements.Herein,Li and Ta-doped KNN nanofibers were fabricated via an electro-spinning process.Co-doping with 6%Li at the A-site and 30%Ta at the B-site induces lattice distortion and an orthorhombic(O)to tetragonal(T)phase transition in the electrospun nanofibers,resulting in a significantly enhanced piezoelectric response,with an average d_(33)*value reaching 110.7 pm/V.The outstanding piezoelectric response gives rise to a remarkable sensitivity(0.3365 V/(N cm^(2)))in a self-powered flexible pressure sensor based on the doped KNN nanofibers,encapsulated in a polydimethylsiloxane matrix.The sensors,when attached to the temple regions,can detect tiny facial motions induced by blinking,enabling the distinction of abnormal blinking patterns associated with mental fatigue and excessive eye use.Additionally,they support real-time,continuous,and unobtrusive eyeball tracking,highlighting their potential as critical components in human-computer interaction and artificial intelligence applications.展开更多
基金supported by the National Natural Science Foundation of China (Grant numbers: 61925405 and 51972102)。
文摘The emergence of inverted perovskite solar cells(PSCs) has attached great attention derived from the potential in improving stability. Charge transporting layer, especially hole transporting layer is crucial for efficient inverted PSCs. Organic materials were used as hole transporting layer previously. Recently, more and more inorganic hole transporting materials have been deployed for further improving the device stability. Nickel oxide(NiOx) as p-type metal oxide, owning high charge mobility and intrinsic stability,has been widely adopted in inverted PSCs. High performance over 20% efficiency has been achieved on NiOx base inverted PSCs. Herein, we have summarized recent progresses and strategies on the NiOx based PSCs, including the synthesis or deposition methods of NiOx, doping and surface modification of NiOx for efficient and stable PSCs. Finally, we will discuss current challenges of utilizing NiOx HTLs in PSCs and attempt to give probable solutions to make further development in efficient as well as stable NiOx based PSCs.
基金financially supported by the National Natural Science Foundation of China(NSFC,52072115,51972102,and U21A20500)Wang J acknowledges the support by A*STAR,under RIE2020 AME Individual Research Grant(IRG)(A20E5c0086),for the research conducted at the National University of Singaporesupported in part by a grant from the Key Laboratory of Wireless Sensor Network&Communication,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences(20190909)。
文摘微/纳尺度压力传感器可以检测来自外部环境的压力,分析所施加力的位置,大小和方向.这种压力传感器在电子屏幕、电子皮肤、运动监测、人工触觉系统等多个领域都有很高的应用需求.本文组装了一种可实现二维映射,基于图案化铌酸钾钠纳米棒阵列的压力传感器矩阵.水热合成的正交相铌酸钾钠纳米棒具有优异的柔性和弹性,同时具有较高的压电性能.因此在组装的压力传感器矩阵中,单个单元尺寸低至200μm,灵敏度可达0.20 V N^(-1),检测限低至20 g,且器件的稳定性高.空间分离的传感器单元能有效避免交叉干扰,使器件能准确地实现自驱动压力成像,精确地分析外部压力刺激.
基金financially supported by the National Natural Science Foundation of China(NSFC,U21A20500,52072115,51972102)the Natural Science Project of Hubei Province in China(2023AFB758,2022CFB518)。
基金supported by the National High-tech R&D Program of China(863 Program)(No.2013AA031903)the National Natural Science Foundation of China under Grant Nos.J1210061 and 50772077.
文摘Pure and noble metal(Pt,Pd,and Au)doped TiO_(2)nanoceramics have been prepared from TiO_(2)nanoparticles through traditional pressing and sintering.For those samples sintered at 550℃,a typical premature sintering occurred,which led to the formation of a highly porous microstructure with a Brunauer-Emmett-Teller(BET)specific surface area of 23 m^(2)/g.At room temperature,only Pt-doped samples showed obvious response to hydrogen,with sensitivities as high as~500 for 1000 ppm H_(2)in N_(2);at 300℃,all samples showed obvious responses to CO,while the responses of noble metal doped samples were much higher than that of the undoped ones.The mechanism for the observed sensing capabilities has been discussed,in which the catalytic effect of Pt for hydrogen is believed responsible for the room-temperature hydrogen sensing capabilities,and the absence of glass frit as commonly used in commercial thick-film metal oxide gas sensors is related to the high sensitivities.It is proposed that much attention should be paid to metal oxide porous nanoceramics in developing gas sensors with high sensitivities and low working temperatures.
基金supported by the National Natural Science Foundation of China (NSFC,Grant Nos.61240056,61405076 and 11304124)
文摘Lead-free Na0.5Bi0.5TiO 3（NBT） nanofibers with the perovskite structure were prepared by the electrospinning method.The nanofibers were about 200-300 nm in diameter and up to several hundred microns in length.The crystal structures and morphologies of the nanofibers were characterized by X-ray diffraction（XRD）,Raman spectroscopy,scanning electron microscopy（SEM）,and transmission electron microscopy（TEM）.The effective piezoelectric property of individual NBT nanofiber was examined by piezoresponse force microscopy（PFM）.The NBT nanofibers crystallized in pure perovskite phase after annealing above 700℃in air and comprised a great number of fine particles with size of 60-80 nm.In addition,the electromechanical energy conversion models for NBT nanofibers were built and demonstrated high voltage output as high as several millivolts.Such a result qualifies NBT nanofibers as a promising candidate for leadfree electromechanical conversion devices.
基金the National Natural Science Foundation of China(11904348,11604032,51772035,51672270 and 52071041)the Fundamental Research Funds for the Central Universities(106112016CDJZR308808)。
文摘Developing an understanding of the physics underlying vibrational phonon modes,which are strongly related to thermal transport,has attracted significant research interest.Herein,we report the successful synthesis of bulk SbCrSe_(3)single crystal and its thermal transport property over the temperature range from 2 to 300 K.Using angle-resolved polarized Raman spectroscopy(ARPRS)and group theory calculation,the vibrational symmetry of each observed Raman mode in the cleaved(001)crystal plane of SbCrSe_(3)is identified for the first time,and then further verified through firstprinciples calculations.The ARPRS results of some Raman modes(e.g.,Ag2~64 cm-1 and Ag 7~185 cm-1)can be adopted to determine the crystalline orientation.More importantly,the temperature dependence of the lattice thermal conductivity(κL)is revealed to be more accurately depicted by the three-phonon scattering processes throughout the measured temperature range,substantiated by in-situ Raman spectroscopy analysis and the model-predictedκL.These results reveal the fundamental physics of thermal transport for SbCrSe_(3)from a completely new perspective and should thus ignite research interest in the thermal properties of other lowdimensional materials using the same strategy.
基金Research supported by the National Science Foundation of China(Grant Nos.11474088,11504099 and 11274103)Natural Science Foundation of Hubei Provincial Department of Education(Grant No.Q20141005)the Applied Basic Research Programs of Wuhan City(Grant No.2014010101010006).
文摘The electronic structure and ferroelectric mechanism of trichloroacetamide were studied using first principles calculations and density functional theory within the generalized gradient approximation.Using both Bader charge and electron deformation density,large molecular spontaneous polarization is found to originate from the charge transfer cause by the strong“push-pull”effect of electron-releasing interacting with electron-withdrawing groups.The intermolecular hydrogen bonds,Ne-H…O,produce dipole moments in adjacent molecules to be aligned with each other.They also reduce the potential energy of the molecular chain threaded by hydrogen bonds.Due to the symmetric crystalline properties,however,the polarization of trichloroacetamide is mostly compensated and therefore small.Using the Berry Phase method,the spontaneous polarization of trichloroacetamide was simulated,and good agreement with the experimental values was found.Considering the polarization characteristics of trichloroacetamide,we constructed a one-dimensional ferroelectric Hamiltonian model to calculate the ferroelectric properties of TCAA.Using the Hamiltonian model,the thermal properties and ferroelectricity of trichloroacetamide were studied using the Monte Carlo method,and the Tc value was calculated.
基金financially supported by the National Natural Science Foundation of China(U21A20500 and 52072115)the Natural Science Foundation(Outstanding Youth Project)of Hubei Province(2023AFA074)+1 种基金the Postdoctoral Fellowship Program of CPSF(GZC20230744)the Postdoctoral Innovation Research Program in Hubei Province(352899)。
文摘Potassium sodium niobate(KNN)-based nanofibers could combine piezoelectric properties with exceptional flexibility and biocompatibility,making them highly promising for flexible sensors in electronic skin and wearable applications.However,the suboptimal piezoelectric performance limits their sensitivity in detecting minute human body motions,such as blinking and eye movements.Herein,Li and Ta-doped KNN nanofibers were fabricated via an electro-spinning process.Co-doping with 6%Li at the A-site and 30%Ta at the B-site induces lattice distortion and an orthorhombic(O)to tetragonal(T)phase transition in the electrospun nanofibers,resulting in a significantly enhanced piezoelectric response,with an average d_(33)*value reaching 110.7 pm/V.The outstanding piezoelectric response gives rise to a remarkable sensitivity(0.3365 V/(N cm^(2)))in a self-powered flexible pressure sensor based on the doped KNN nanofibers,encapsulated in a polydimethylsiloxane matrix.The sensors,when attached to the temple regions,can detect tiny facial motions induced by blinking,enabling the distinction of abnormal blinking patterns associated with mental fatigue and excessive eye use.Additionally,they support real-time,continuous,and unobtrusive eyeball tracking,highlighting their potential as critical components in human-computer interaction and artificial intelligence applications.
