Cesium tungsten bronze （CsxW03） powders were synthesized by hydrothermal reaction at 190 ℃ by using sodium tungstate and cesium carbonate as raw materials, and the effects of N2 annealing on the microstructure and ...Cesium tungsten bronze （CsxW03） powders were synthesized by hydrothermal reaction at 190 ℃ by using sodium tungstate and cesium carbonate as raw materials, and the effects of N2 annealing on the microstructure and near-infrared （NIR） shielding as well as heat insulation properties of CsxW03 were investigated. The results indicated that the synthesized CsxW03 powders exhibited hexagohal CSo.32WO3 crystal structure, and subsequent N2 annealing could further improve the crystallinity of CsxW03 particles. Moreover, the NIR shielding and heat insulation properties of CsxW03 could be further improved after N2 annealing at appropriate temperature for a period of time. Particularly, the 500 ℃-annealed CsxW03 products in the N2 atmosphere showed the best NIR shielding and heat insulation properties. When the N2 annealing temperature was higher than 700 ℃, the NIR shielding properties decreased again. The 800 ℃-annealed samples in the N2 atmosphere showed higher visible light transmittance, however, the NIR shielding properties were lower than that of the non-annealed samples.展开更多
Cesium as a kind of alkali metals has widely been used in catalysis,medicine,biology,magnetic fluid power and other high-tech fields(Liao and Yang,2012;Cao et al.,2011;Wang et al.,2011).Although there was abundant of
Interface engineering has been regarded as an effective and noninvasive means to optimize the performance of perovskite solar cells(PSCs).Here,doping engineering of a ZnO electron transport layer(ETL)and CsPbI3/ZnO in...Interface engineering has been regarded as an effective and noninvasive means to optimize the performance of perovskite solar cells(PSCs).Here,doping engineering of a ZnO electron transport layer(ETL)and CsPbI3/ZnO interface engineering via introduction of an interfacial layer are employed to improve the performances of CsPbI3-based PSCs.The results show that when introducing a TiO2 buffer layer while increasing the ZnO layer doping concentration,the open-circuit voltage,power conversion efficiency,and fill factor of the CsPbI3-based PSCs can be improved to 1.31 V,21.06%,and 74.07%,respectively,which are superior to those of PSCs only modified by the TiO2 buffer layer or high-concentration doping of ZnO layer.On the one hand,the buffer layer relieves the band bending and structural disorder of CsPbI3.On the other hand,the increased doping concentration of the ZnO layer improves the conductivity of the TiO2/ZnO bilayer ETL because of the strong interaction between the TiO2 and ZnO layers.However,such phenomena are not observed for those of a PCBM/ZnO bilayer ETL because of the weak interlayer interaction of the PCBM/ZnO interface.These results provide a comprehensive understanding of the CsPbI3/ZnO interface and suggest a guideline to design high-performance PSCs.展开更多
Fabricating high-quality cesium lead chloride(CsPbCl_3) perovskite nanowires(NWs) with dimension below 10 nm is not only of interests in fundamental physics, but also holds the great promise for optoelectronic applica...Fabricating high-quality cesium lead chloride(CsPbCl_3) perovskite nanowires(NWs) with dimension below 10 nm is not only of interests in fundamental physics, but also holds the great promise for optoelectronic applications. Herein, ultrathin CsPbCl_3 NWs with height of ～7 nm, have been achieved via vapor phase deposition method. Power and temperature-dependent photoluminescence(PL) spectroscopy is performed to explore the emission properties of the CsPbCl_3 NWs. Strong free exciton recombination is observed at ～3.02 eV as the temperature(T) is 78-294 K with binding energy of ～ 37.5 meV. With the decreasing of T, the PL peaks exhibit a first blueshift by 2 meV for T ～ 294-190 K and then a redshift by 4 meV for T ～ 190-78 K. The exciton–optical phonon interaction plays a major role in the linewidth broadening of the PL spectra with average optical phonon energy of ～48.0 meV and the interaction coefficient of 203.9 meV. These findings advance the fabrication of low dimensional CsPbCl_3 perovskite and provide insights into the photophysics of the CsPbCl_3 perovskite.展开更多
Yellow light-emitting diodes(LEDs) as soft light have attracted abundant attention in lithography room, museum and art gallery. However, the development of efficient yellow LEDs lags behind green and blue LEDs, and th...Yellow light-emitting diodes(LEDs) as soft light have attracted abundant attention in lithography room, museum and art gallery. However, the development of efficient yellow LEDs lags behind green and blue LEDs, and the available perovskites yellow LEDs suffer from the instability. Herein, a pressure-assisted cooling method is proposed to grow lead-free CsCu2I3single crystals, which possess uniform surface morphology and enhanced photoluminescence quantum yield(PLQY) stability, with only 10% PLQY losses after being stored in air after 5000 h.Then, the single crystals used for yellow LEDs without encapsulation exhibit a decent Correlated Color Temperature(CCT) of 4290 K, a Commission Internationale de l’Eclairage(CIE) coordinate of(0.38, 0.41), and an excellent 570-h operating stability under heating temperature of 100°C. Finally, the yellow LEDs facilitate the application in wireless visible light communication(VLC), which show a-3 dB bandwidth of 21.5 MHz and a high achievable data rate of 219.2 Mbps by using orthogonal frequency division multiplexing(OFDM) modulation with adaptive bit loading. The present work not only promotes the development of lead-free single crystals, but also inspires the potential of CsCu2I3in the field of yellow illumination and wireless VLC.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51278074)the Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(the[42nd,20111139])
文摘Cesium tungsten bronze （CsxW03） powders were synthesized by hydrothermal reaction at 190 ℃ by using sodium tungstate and cesium carbonate as raw materials, and the effects of N2 annealing on the microstructure and near-infrared （NIR） shielding as well as heat insulation properties of CsxW03 were investigated. The results indicated that the synthesized CsxW03 powders exhibited hexagohal CSo.32WO3 crystal structure, and subsequent N2 annealing could further improve the crystallinity of CsxW03 particles. Moreover, the NIR shielding and heat insulation properties of CsxW03 could be further improved after N2 annealing at appropriate temperature for a period of time. Particularly, the 500 ℃-annealed CsxW03 products in the N2 atmosphere showed the best NIR shielding and heat insulation properties. When the N2 annealing temperature was higher than 700 ℃, the NIR shielding properties decreased again. The 800 ℃-annealed samples in the N2 atmosphere showed higher visible light transmittance, however, the NIR shielding properties were lower than that of the non-annealed samples.
基金Financial support from the State Surface Project of National Natural Science of China (21276194)the Key Pillar Program of Tianjin Municipal Science and Technology (11ZCKGX02800)the Specialized Research Fund for the Doctoral Program of Chinese Higher Education (20101208110003)
文摘Cesium as a kind of alkali metals has widely been used in catalysis,medicine,biology,magnetic fluid power and other high-tech fields(Liao and Yang,2012;Cao et al.,2011;Wang et al.,2011).Although there was abundant of
基金financially supported by the National Natural Science Foundation of China(Nos.61604119,61704131,and 61804111)Initiative Postdocs Supporting Program(No.BX20180234)+2 种基金China Postdoctoral Science Foundation(No.2018M643578)Young Elite Scientists Sponsorship Program by CAST(2016QNRC001)Fundamental Research Funds for the Central Universities.
文摘Interface engineering has been regarded as an effective and noninvasive means to optimize the performance of perovskite solar cells(PSCs).Here,doping engineering of a ZnO electron transport layer(ETL)and CsPbI3/ZnO interface engineering via introduction of an interfacial layer are employed to improve the performances of CsPbI3-based PSCs.The results show that when introducing a TiO2 buffer layer while increasing the ZnO layer doping concentration,the open-circuit voltage,power conversion efficiency,and fill factor of the CsPbI3-based PSCs can be improved to 1.31 V,21.06%,and 74.07%,respectively,which are superior to those of PSCs only modified by the TiO2 buffer layer or high-concentration doping of ZnO layer.On the one hand,the buffer layer relieves the band bending and structural disorder of CsPbI3.On the other hand,the increased doping concentration of the ZnO layer improves the conductivity of the TiO2/ZnO bilayer ETL because of the strong interaction between the TiO2 and ZnO layers.However,such phenomena are not observed for those of a PCBM/ZnO bilayer ETL because of the weak interlayer interaction of the PCBM/ZnO interface.These results provide a comprehensive understanding of the CsPbI3/ZnO interface and suggest a guideline to design high-performance PSCs.
基金supported by National Natural Science Foundation of China(Nos.61774003,61521004,51472080)National Key Research and Development Program of China(Nos.2017YFA0205700,2017YFA0304600)+1 种基金Open Research Fund Program of the State Key Laboratory of Low-dimensional Quantum Physics(No.KF201706)Excellent Youth Foundation of Hubei Province(No.2017CFA038)
文摘Fabricating high-quality cesium lead chloride(CsPbCl_3) perovskite nanowires(NWs) with dimension below 10 nm is not only of interests in fundamental physics, but also holds the great promise for optoelectronic applications. Herein, ultrathin CsPbCl_3 NWs with height of ～7 nm, have been achieved via vapor phase deposition method. Power and temperature-dependent photoluminescence(PL) spectroscopy is performed to explore the emission properties of the CsPbCl_3 NWs. Strong free exciton recombination is observed at ～3.02 eV as the temperature(T) is 78-294 K with binding energy of ～ 37.5 meV. With the decreasing of T, the PL peaks exhibit a first blueshift by 2 meV for T ～ 294-190 K and then a redshift by 4 meV for T ～ 190-78 K. The exciton–optical phonon interaction plays a major role in the linewidth broadening of the PL spectra with average optical phonon energy of ～48.0 meV and the interaction coefficient of 203.9 meV. These findings advance the fabrication of low dimensional CsPbCl_3 perovskite and provide insights into the photophysics of the CsPbCl_3 perovskite.
基金This work is funded by National Natural Science Foundation of China(Nos.61904023,11974063)Fundamental Research Funds for the Cen-tral Universities(2021CDJQY-022)Natural Science Foundation of Chongqing(No.cstc2019jcyj-bshX0078,cstc2020jcyj-jqX0028).
文摘Yellow light-emitting diodes(LEDs) as soft light have attracted abundant attention in lithography room, museum and art gallery. However, the development of efficient yellow LEDs lags behind green and blue LEDs, and the available perovskites yellow LEDs suffer from the instability. Herein, a pressure-assisted cooling method is proposed to grow lead-free CsCu2I3single crystals, which possess uniform surface morphology and enhanced photoluminescence quantum yield(PLQY) stability, with only 10% PLQY losses after being stored in air after 5000 h.Then, the single crystals used for yellow LEDs without encapsulation exhibit a decent Correlated Color Temperature(CCT) of 4290 K, a Commission Internationale de l’Eclairage(CIE) coordinate of(0.38, 0.41), and an excellent 570-h operating stability under heating temperature of 100°C. Finally, the yellow LEDs facilitate the application in wireless visible light communication(VLC), which show a-3 dB bandwidth of 21.5 MHz and a high achievable data rate of 219.2 Mbps by using orthogonal frequency division multiplexing(OFDM) modulation with adaptive bit loading. The present work not only promotes the development of lead-free single crystals, but also inspires the potential of CsCu2I3in the field of yellow illumination and wireless VLC.
