Selective emitters are crucial as the key component determining the energy conversion efficiency of radioisotope thermophotovoltaic(RTPV)systems.Developing selective emitter materials with high selective emissivity,hi...Selective emitters are crucial as the key component determining the energy conversion efficiency of radioisotope thermophotovoltaic(RTPV)systems.Developing selective emitter materials with high selective emissivity,high spectral efficiency and excellent high-temperature stability can effectively improve the energy conversion efficiency and service life of RTPV systems.To adjust the selective emissivity and spectral efficiency,a series of rare earth tantalate selective emitters(Er(Ta_(1−x)Nb_(x))O_(4)(0≤x≤0.2))matching GaSb batteries were prepared by high-temperature solidstate reaction and pressureless sintering method.The as-prepared Er(Ta_(1−x)Nb_(x))O_(4)(0≤x≤0.2)ceramics exhibit high emissivity(49%–93%)in the selective band(1.40–1.60μm),high spectral efficiency(59.46%–62.12%)and excellent high-temperature stability at 1400℃.On one hand,doping Nb^(5+)into the B-site changes the crystal local structure symmetry around Er^(3+),which promotes the f–f transition of Er^(3+)and enhances the selective emission performance.On the other hand,doping Nb^(5+)ions into the B-site can alter the bandgap and oxygen vacancy concentration to suppress non-selective emissivity.Increasing the selective emissivity and reducing the non-selective emissivity is beneficial for improving the spectral efficiency of selective emitters.Hence,the selective emissivity and spectral efficiency of Er(Ta_(1−x)Nb_(x))O_(4)(0≤x≤0.2)can be effectively enhanced through compositional design,providing a new strategy for developing selective emitter materials for RTPV applications.展开更多
Micro/nanostructures play a key role in tuning the radiative properties of materials and have been applied to high-temperature energy conversion systems for improved performance.Among the various radiative properties,...Micro/nanostructures play a key role in tuning the radiative properties of materials and have been applied to high-temperature energy conversion systems for improved performance.Among the various radiative properties,spectral emittance is of integral importance for the design and analysis of materials that function as radiative absorbers or emitters.This paper presents an overview of the spectral emittance measurement techniques using both the direct and indirect methods.Besides,several micro/nanostructures are also introduced,and a special emphasis is placed on the emissometers developed for characterizing engineered micro/nanostructures in high-temperature applications(e.g.,solar energy conversion and thermophotovoltaic devices).In addition,both experimental facilities and measured results for different materials are summarized.Furthermore,future prospects in developing instrumentation and micro/nanostructured surfaces for practical applications are also outlined.This paper provides a comprehensive source of information for the application of micro/nanostructures in high-temperature energy conversion engineering.展开更多
基金supported by the National Natural Science Foundation of China(No.52402093)the Self-deployment Project Research Programs of Haixi Institutes,Chinese Academy of Sciences(No.CXZX-2023-JQ07)+3 种基金the National Key R&D Program of China(No.2022YFB3504302)the Young Elite Scientists Sponsorship Program by CAST(No.YESS20210336)the XMIREM Autonomously Deployment Project(Nos.2023GG03 and 2023CX01)the Natural Science Foundation of Xiamen(No.3502Z202472048).
文摘Selective emitters are crucial as the key component determining the energy conversion efficiency of radioisotope thermophotovoltaic(RTPV)systems.Developing selective emitter materials with high selective emissivity,high spectral efficiency and excellent high-temperature stability can effectively improve the energy conversion efficiency and service life of RTPV systems.To adjust the selective emissivity and spectral efficiency,a series of rare earth tantalate selective emitters(Er(Ta_(1−x)Nb_(x))O_(4)(0≤x≤0.2))matching GaSb batteries were prepared by high-temperature solidstate reaction and pressureless sintering method.The as-prepared Er(Ta_(1−x)Nb_(x))O_(4)(0≤x≤0.2)ceramics exhibit high emissivity(49%–93%)in the selective band(1.40–1.60μm),high spectral efficiency(59.46%–62.12%)and excellent high-temperature stability at 1400℃.On one hand,doping Nb^(5+)into the B-site changes the crystal local structure symmetry around Er^(3+),which promotes the f–f transition of Er^(3+)and enhances the selective emission performance.On the other hand,doping Nb^(5+)ions into the B-site can alter the bandgap and oxygen vacancy concentration to suppress non-selective emissivity.Increasing the selective emissivity and reducing the non-selective emissivity is beneficial for improving the spectral efficiency of selective emitters.Hence,the selective emissivity and spectral efficiency of Er(Ta_(1−x)Nb_(x))O_(4)(0≤x≤0.2)can be effectively enhanced through compositional design,providing a new strategy for developing selective emitter materials for RTPV applications.
基金This work was supported by the China Scholarship Council(No.201806320236)the Academic Award for Outstanding Doctoral Candidates of Zhejiang University(No.2018071)+1 种基金the Key Research and Development Program of Ningxia Hui Autonomous Region(No.2018BCE01004)the US Department of Energy's Office of Energy Efficiency and Renewable Energy(EERE)under the Solar Energy Technologies Office.
文摘Micro/nanostructures play a key role in tuning the radiative properties of materials and have been applied to high-temperature energy conversion systems for improved performance.Among the various radiative properties,spectral emittance is of integral importance for the design and analysis of materials that function as radiative absorbers or emitters.This paper presents an overview of the spectral emittance measurement techniques using both the direct and indirect methods.Besides,several micro/nanostructures are also introduced,and a special emphasis is placed on the emissometers developed for characterizing engineered micro/nanostructures in high-temperature applications(e.g.,solar energy conversion and thermophotovoltaic devices).In addition,both experimental facilities and measured results for different materials are summarized.Furthermore,future prospects in developing instrumentation and micro/nanostructured surfaces for practical applications are also outlined.This paper provides a comprehensive source of information for the application of micro/nanostructures in high-temperature energy conversion engineering.
