Organic-inorganic hybrid perovskites attract considerable attention owing to their applications in high-efficiency solar cells and light emission. Compared with three-dimensional perovskites, two-dimensional （2D） la...Organic-inorganic hybrid perovskites attract considerable attention owing to their applications in high-efficiency solar cells and light emission. Compared with three-dimensional perovskites, two-dimensional （2D） layered hybrid perovskites have a higher exciton binding energy and potentially higher light- emission efficiency. The growth of high-quality crystalline 2D perovskites with a well-defined nanoscale morphology is desirable because they can be suitable building blocks for integrated optoelectronics and （nano）photonics. Herein, we report the facile solution growth of single-crystal microplates of 2D perovskites based on a 2-phenylethylammonium （C6HsCH2CH2NHG PEA） cation, （PEA）2PbX- （X = Br, I）, with a well-defined rectangular geometry and nanoscale thickness through a dissolution-recrystallization process. The crystal structures of （PEA）2PbX4 are first confirmed using single-crystal X-ray diffraction. A solution-phase transport-growth process is developed to grow microplates with a typical size of tens of micrometers and thickness of hundreds of nanometers on another clean substrate different from the substrate coated with lead-acetate precursor film. Surface-topography analysis suggests that the formation of the 2D microplates is likely driven by the wedding-cake growth mechanism. Through halide alloying, the photoluminescence emission of （PEA）2Pb（Br, I）4 perovskites with a narrow peak bandwidth is readily tuned from violet （-410 nm） to green （-530 nm）.展开更多
One-dimensional nanowire is an important candidate for lead-halide perovskite-based photonic detectors and solar cells. Its surface population, diameter, and growth direction, etc., are critical for device performance...One-dimensional nanowire is an important candidate for lead-halide perovskite-based photonic detectors and solar cells. Its surface population, diameter, and growth direction, etc., are critical for device performance. In this research,we carried out a detailed study on electron transfer process at the interface of nanowire CH_(3) NH_(3) PbI_(3)(N-MAPbI_(3))/Phenyl C61 butyric acid methyl-ester synonym(PCBM), as well as the interface of compact CH_(3) NH_(3) PbI_(3)(C-MAPbI_(3))/PCBM by transient absorption spectroscopy. By comparing the carrier recombination dynamics of N-MAPbI_(3), N-MAPbI_(3)/PCBM,C-MAPbI_(3), and C-MAPbI_(3)/PCBM from picosecond(ps) to hundred nanosecond(ns) time scale, it is demonstrated that electron transfer at N-MAPbI_(3)/PCBM interface is less efficient than that at C-MAPbI_(3)/PCBM interface. In addition, electron transfer efficiency at C-MAPbI_(3)/PCBM interface was found to be excitation density-dependent, and it reduces with photo-generation carrier concentration increasing in a range from 1.0 × 1018 cm^(-3)–4.0 × 1018 cm^(-3). Hot electron transfer,which leads to acceleration of electron transfer between the interfaces, was also visualized as carrier concentration increases from 1.0 × 10^(18) cm^(-3)–2.2 × 10^(18) cm^(-3).展开更多
Perovskites show exciting potential for photoelectric applications,especially for light-emitting diodes(LEDs),owing to their intrinsically high photoluminescence efficiency and color purity.With efforts made over the ...Perovskites show exciting potential for photoelectric applications,especially for light-emitting diodes(LEDs),owing to their intrinsically high photoluminescence efficiency and color purity.With efforts made over the last 5 years,the external quantum efficiency(EQE)of lead-halide perovskite-based LEDs has sharply increased beyond 20%,which is comparable to the performance of existing lighting technology.Strategies,including defect passivation,the formation of low-dimensional quantum-well structure perovskites,and a combination of appropriate electron and hole transport materials in electroluminescent devices.展开更多
Defect states in perovskite films restrict the interfacial stability and open-circuit voltage of perovskite solar cells.Here,aiming at superior interfacial passivation,we investigate the reconfiguration of perovskite ...Defect states in perovskite films restrict the interfacial stability and open-circuit voltage of perovskite solar cells.Here,aiming at superior interfacial passivation,we investigate the reconfiguration of perovskite interface by the interaction between a series of quaternary ammonium bromides(QAB)and lead—halide(Pb—X)octahedrons.Bromide—iodide substitution reaction or R4NBr addition reaction may occur on the perovskite surface,which is related to the steric hindrance of quaternary ammonium cations.On this basis,the perovskite surface morphology,band structure,growth orientation and defect states are reconstructed via the R4NBr addition reaction.This ordered lead—halide adduct could effectively repair the imperfect perovskite/hole transportation layer interface to suppress non-radiative recombination and ion migration toward ultralong carrier lifetime surpassing 10µs.The resulting perovskite solar cells yield the efficiency of 23.89%with steady-state efficiency of 23.70%.The passivated cells can sustain 86%of initial efficiency after 200-h operation,which is attributed to the passivation effect and hydrophobic characteristics.This work provides an avenue for reconfiguring perovskite surface by QABs.展开更多
由化石能源消耗所引发的能源危机与环境污染,已成为了人类社会可持续发展亟待解决的一个首要问题。可见光催化技术利用太阳光为能源,通过光解水制氢、CO_(2)还原、污染物降解等过程为从根本上解决上述问题提供了一个有效途径,对可持续...由化石能源消耗所引发的能源危机与环境污染,已成为了人类社会可持续发展亟待解决的一个首要问题。可见光催化技术利用太阳光为能源,通过光解水制氢、CO_(2)还原、污染物降解等过程为从根本上解决上述问题提供了一个有效途径,对可持续发展战略具有重要意义。金属卤化铅钙钛矿(lead metal halide perovskite,LMHP)型光催化剂因其多样的晶体结构、合适的禁带宽度及丰富的空位,表现出优异的光电性能,为实现光催化剂的性能调控提供了多种手段,成为了当前的一个研究热点。近年来,金属卤化铅钙钛矿的研究与应用发展非常迅速,特别是在太阳能驱动的应用中,取得了一系列成果。详细综述了金属卤化铅钙钛矿型光催化材料在可见光催化能源开发和环境污染治理领域的研究进展,为进一步开发环保高效的光催化剂新材料提供新的思路。展开更多
Two new low dimensional lead（Ⅱ） diiodide complexes with 1,10-phenanthroline- 5,6-dione （Phendione）, PbI2（Phendione）2 （1） and PbI2（Phendione）（DMSO）2 （2）, have been synthesized by solution processes and s...Two new low dimensional lead（Ⅱ） diiodide complexes with 1,10-phenanthroline- 5,6-dione （Phendione）, PbI2（Phendione）2 （1） and PbI2（Phendione）（DMSO）2 （2）, have been synthesized by solution processes and structurally determined by X-ray diffraction method. Both compounds are mononuclear with the lead centers being in highly distorted octahedral environments. Hydrogen bonds and π-π stacking interactions contribute to the structural extension and stabilization. Theoretical calculations based on the DFT/B3LYP level indicate that the introduction of electronic donating groups on the phenanthroline ring can improve the electron density of nitrogen atoms, and they can replace part of the bridged iodine atoms to lower the structural dimensions. Experimental band gaps of about 2.07 and 1.97 eV indicate their semiconductor nature.展开更多
High-performance multiphoton-pumped lasers based on cesium lead halide perovskite nanostructures are promising for nonlinear optics and practical frequency upconversion devices in integrated photonics. However, the pe...High-performance multiphoton-pumped lasers based on cesium lead halide perovskite nanostructures are promising for nonlinear optics and practical frequency upconversion devices in integrated photonics. However, the performance of such lasers is highly dependent on the quality of the material and cavity, which makes their fabrication challenging. Herein, we demonstrate that cesium lead halide perovskite triangular nanorods fabricated via vapor methods can serve as gain media and effective cavities for multiphoton-pumped lasers. We observed blue-shifts of the lasing modes in the excitation fluence-dependent lasing spectra at increased excitation powers, which fits well with the dynamics of Burstein-Moss shifts caused by the band filling effect. Moreover, efficient multiphoton lasing in CsPbBr3 nanorods can be realized in a wide excitation wavelength range （700-1,400 nm）. The dynamics of multiphoton lasing were investigated by time-resolved photoluminescence spectroscopy, which indicated that an electron-hole plasma is responsible for the multiphoton-pumped lasing. This work could lead to new opportunities and applications for cesium lead halide perovskite nanostructures in frequency upconversion lasing devices and optical interconnect systems.展开更多
In this work, the pseudohalide thiocyanate has been demonstrated as a promising alternative to the halide anion to engineer optoelectronic properties of inorganic/ organic hybrid perovskites because it exhibits better...In this work, the pseudohalide thiocyanate has been demonstrated as a promising alternative to the halide anion to engineer optoelectronic properties of inorganic/ organic hybrid perovskites because it exhibits better chemical stability than the halide anion. Previous reports have suggested that the ionic radii and electronegativity of SCN- is close to that of I^-; the SCN^- doped CH3NH3PbI3 exhibited similar optical properties as pure CH3NH3PbI3. Consequently, it was expected that doping of CsPbBr3 perovskite with SCN^- would result in band gap narrowing. Interestingly, the photoluminescent all-inorganic CsPbBr3 perovskite nanocrystals exhibit an abnormal blue shift in optical properties and improvement of the crystallinity when successfully doped by SCN^-. Combined experimental and theoretical investigations revealed that doping of the CsPbBr3 perovskite with the rod-like SCN^- anion introduced disorder in the crystal lattice, leading to its expansion, and impacted the electronic structure of the perovskite with band gap broadening.展开更多
As a direct bandgap semiconductor, organic-inorganic lead halide perovskite (MAPbX3, MA = CH3NH3, X =Cl, Br, I) have been considered as promising materials for laser due to their excellent optoelectronic properties. T...As a direct bandgap semiconductor, organic-inorganic lead halide perovskite (MAPbX3, MA = CH3NH3, X =Cl, Br, I) have been considered as promising materials for laser due to their excellent optoelectronic properties. The perovskite materials with ID and 2D shapes were widely prepared and studied for Fabry-Perot mode and whispering-gallery-mode (WGM) microcavities, but cuboid-shape is rarely reported. In this work, we successfully fabricated single crystal cuboid-shaped MAPbBr3 perovskite w让h different morphologies, named microcuboid-MAPbBr3 (M-MAPbBr3) and multi-step-MAPbBr3 (MSMAPbBr3), via solvothermal method. Furthermore, the as-prepared *crystals excitonic recombination lifetime under different pumping energy density was studied by time-resolved photoiuminescence (TRPL). Based on controllable morphology and remarkable lasing properties, these cuboid shaped single crystal perovskite could be a promising candidate for small laser, and other optoelectronic devices.展开更多
文摘Organic-inorganic hybrid perovskites attract considerable attention owing to their applications in high-efficiency solar cells and light emission. Compared with three-dimensional perovskites, two-dimensional （2D） layered hybrid perovskites have a higher exciton binding energy and potentially higher light- emission efficiency. The growth of high-quality crystalline 2D perovskites with a well-defined nanoscale morphology is desirable because they can be suitable building blocks for integrated optoelectronics and （nano）photonics. Herein, we report the facile solution growth of single-crystal microplates of 2D perovskites based on a 2-phenylethylammonium （C6HsCH2CH2NHG PEA） cation, （PEA）2PbX- （X = Br, I）, with a well-defined rectangular geometry and nanoscale thickness through a dissolution-recrystallization process. The crystal structures of （PEA）2PbX4 are first confirmed using single-crystal X-ray diffraction. A solution-phase transport-growth process is developed to grow microplates with a typical size of tens of micrometers and thickness of hundreds of nanometers on another clean substrate different from the substrate coated with lead-acetate precursor film. Surface-topography analysis suggests that the formation of the 2D microplates is likely driven by the wedding-cake growth mechanism. Through halide alloying, the photoluminescence emission of （PEA）2Pb（Br, I）4 perovskites with a narrow peak bandwidth is readily tuned from violet （-410 nm） to green （-530 nm）.
基金supported by the National Natural Science Foundation of China (Grant Nos. 21503066 and 61904048)the Fundamental Research Project from Shenzhen Science and Technology Innovation Committee (Grant No. JCYJ20180302174021198)+2 种基金the Natural Science Foundation of Hebei ProvinceChina(Grant No. F2017201136)the Foundation of Hebei Educational Committee (Grant No. ZC2016003)。
文摘One-dimensional nanowire is an important candidate for lead-halide perovskite-based photonic detectors and solar cells. Its surface population, diameter, and growth direction, etc., are critical for device performance. In this research,we carried out a detailed study on electron transfer process at the interface of nanowire CH_(3) NH_(3) PbI_(3)(N-MAPbI_(3))/Phenyl C61 butyric acid methyl-ester synonym(PCBM), as well as the interface of compact CH_(3) NH_(3) PbI_(3)(C-MAPbI_(3))/PCBM by transient absorption spectroscopy. By comparing the carrier recombination dynamics of N-MAPbI_(3), N-MAPbI_(3)/PCBM,C-MAPbI_(3), and C-MAPbI_(3)/PCBM from picosecond(ps) to hundred nanosecond(ns) time scale, it is demonstrated that electron transfer at N-MAPbI_(3)/PCBM interface is less efficient than that at C-MAPbI_(3)/PCBM interface. In addition, electron transfer efficiency at C-MAPbI_(3)/PCBM interface was found to be excitation density-dependent, and it reduces with photo-generation carrier concentration increasing in a range from 1.0 × 1018 cm^(-3)–4.0 × 1018 cm^(-3). Hot electron transfer,which leads to acceleration of electron transfer between the interfaces, was also visualized as carrier concentration increases from 1.0 × 10^(18) cm^(-3)–2.2 × 10^(18) cm^(-3).
基金supported by the Young 1000 Talents Global Recruitment program of China and Chinese Academy of Sciences.
文摘Perovskites show exciting potential for photoelectric applications,especially for light-emitting diodes(LEDs),owing to their intrinsically high photoluminescence efficiency and color purity.With efforts made over the last 5 years,the external quantum efficiency(EQE)of lead-halide perovskite-based LEDs has sharply increased beyond 20%,which is comparable to the performance of existing lighting technology.Strategies,including defect passivation,the formation of low-dimensional quantum-well structure perovskites,and a combination of appropriate electron and hole transport materials in electroluminescent devices.
基金supported by the National Natural Science Foundation of China (51872321, 11874402, 52172260, 52072402,52102332 and 52102267)Ministry of Sciecnce and Technology of the People’s Republic of China (2021YFB3800103)the Fundamental Research Fund for the Central University,Nankai University (023/63213101)。
文摘Defect states in perovskite films restrict the interfacial stability and open-circuit voltage of perovskite solar cells.Here,aiming at superior interfacial passivation,we investigate the reconfiguration of perovskite interface by the interaction between a series of quaternary ammonium bromides(QAB)and lead—halide(Pb—X)octahedrons.Bromide—iodide substitution reaction or R4NBr addition reaction may occur on the perovskite surface,which is related to the steric hindrance of quaternary ammonium cations.On this basis,the perovskite surface morphology,band structure,growth orientation and defect states are reconstructed via the R4NBr addition reaction.This ordered lead—halide adduct could effectively repair the imperfect perovskite/hole transportation layer interface to suppress non-radiative recombination and ion migration toward ultralong carrier lifetime surpassing 10µs.The resulting perovskite solar cells yield the efficiency of 23.89%with steady-state efficiency of 23.70%.The passivated cells can sustain 86%of initial efficiency after 200-h operation,which is attributed to the passivation effect and hydrophobic characteristics.This work provides an avenue for reconfiguring perovskite surface by QABs.
文摘由化石能源消耗所引发的能源危机与环境污染,已成为了人类社会可持续发展亟待解决的一个首要问题。可见光催化技术利用太阳光为能源,通过光解水制氢、CO_(2)还原、污染物降解等过程为从根本上解决上述问题提供了一个有效途径,对可持续发展战略具有重要意义。金属卤化铅钙钛矿(lead metal halide perovskite,LMHP)型光催化剂因其多样的晶体结构、合适的禁带宽度及丰富的空位,表现出优异的光电性能,为实现光催化剂的性能调控提供了多种手段,成为了当前的一个研究热点。近年来,金属卤化铅钙钛矿的研究与应用发展非常迅速,特别是在太阳能驱动的应用中,取得了一系列成果。详细综述了金属卤化铅钙钛矿型光催化材料在可见光催化能源开发和环境污染治理领域的研究进展,为进一步开发环保高效的光催化剂新材料提供新的思路。
基金the support of National Natural Science Foundation of China(Nos.21271043)
文摘Two new low dimensional lead（Ⅱ） diiodide complexes with 1,10-phenanthroline- 5,6-dione （Phendione）, PbI2（Phendione）2 （1） and PbI2（Phendione）（DMSO）2 （2）, have been synthesized by solution processes and structurally determined by X-ray diffraction method. Both compounds are mononuclear with the lead centers being in highly distorted octahedral environments. Hydrogen bonds and π-π stacking interactions contribute to the structural extension and stabilization. Theoretical calculations based on the DFT/B3LYP level indicate that the introduction of electronic donating groups on the phenanthroline ring can improve the electron density of nitrogen atoms, and they can replace part of the bridged iodine atoms to lower the structural dimensions. Experimental band gaps of about 2.07 and 1.97 eV indicate their semiconductor nature.
基金Acknowledgements All authors are grateful to the National Natural Science Foundation of China （Nos. 51525202, 61574054, 61505051 and 61474040）, the Hunan province science and technology plan （Nos. 2014FJ2001 and 2014TT1004）, the Aid program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, and the Fundamental Research Funds for the Central Universities.
文摘High-performance multiphoton-pumped lasers based on cesium lead halide perovskite nanostructures are promising for nonlinear optics and practical frequency upconversion devices in integrated photonics. However, the performance of such lasers is highly dependent on the quality of the material and cavity, which makes their fabrication challenging. Herein, we demonstrate that cesium lead halide perovskite triangular nanorods fabricated via vapor methods can serve as gain media and effective cavities for multiphoton-pumped lasers. We observed blue-shifts of the lasing modes in the excitation fluence-dependent lasing spectra at increased excitation powers, which fits well with the dynamics of Burstein-Moss shifts caused by the band filling effect. Moreover, efficient multiphoton lasing in CsPbBr3 nanorods can be realized in a wide excitation wavelength range （700-1,400 nm）. The dynamics of multiphoton lasing were investigated by time-resolved photoluminescence spectroscopy, which indicated that an electron-hole plasma is responsible for the multiphoton-pumped lasing. This work could lead to new opportunities and applications for cesium lead halide perovskite nanostructures in frequency upconversion lasing devices and optical interconnect systems.
基金This work was sponsored by the National Natural Science Foundation of China （Nos. 21475021, 21427807, 61722403, 11404131, and 11674121）, the Natural Science Foundation of Jiangsu Province （No. BK20141331）, the Fundamental Research Funds for the Central Universities, Program for JLU Science and Technology Innovative Research Team, the Special Fund for Talent Exploitation in Jilin Province of China, Jiangsu provincial financial support of fundamental conditions and science and technology for people＇s livelihood for Jiangsu key laboratory of advanced metallic materials （No. BM2007204）.
文摘In this work, the pseudohalide thiocyanate has been demonstrated as a promising alternative to the halide anion to engineer optoelectronic properties of inorganic/ organic hybrid perovskites because it exhibits better chemical stability than the halide anion. Previous reports have suggested that the ionic radii and electronegativity of SCN- is close to that of I^-; the SCN^- doped CH3NH3PbI3 exhibited similar optical properties as pure CH3NH3PbI3. Consequently, it was expected that doping of CsPbBr3 perovskite with SCN^- would result in band gap narrowing. Interestingly, the photoluminescent all-inorganic CsPbBr3 perovskite nanocrystals exhibit an abnormal blue shift in optical properties and improvement of the crystallinity when successfully doped by SCN^-. Combined experimental and theoretical investigations revealed that doping of the CsPbBr3 perovskite with the rod-like SCN^- anion introduced disorder in the crystal lattice, leading to its expansion, and impacted the electronic structure of the perovskite with band gap broadening.
基金supported by the National Natural Science Foundation of China(11674023,51331002,51622205,61675027,61505010,51502018,51525202 and 51432005)111 Project(B170003)+2 种基金the National Key Research and Development Program of China(2016YFA0202703)Beijing Natural Science Foundation(4181004 and 4182080)the ‘‘Thousand Talents” Program of China for Pioneering Researchers and Innovative Teams(U1404619)
文摘As a direct bandgap semiconductor, organic-inorganic lead halide perovskite (MAPbX3, MA = CH3NH3, X =Cl, Br, I) have been considered as promising materials for laser due to their excellent optoelectronic properties. The perovskite materials with ID and 2D shapes were widely prepared and studied for Fabry-Perot mode and whispering-gallery-mode (WGM) microcavities, but cuboid-shape is rarely reported. In this work, we successfully fabricated single crystal cuboid-shaped MAPbBr3 perovskite w让h different morphologies, named microcuboid-MAPbBr3 (M-MAPbBr3) and multi-step-MAPbBr3 (MSMAPbBr3), via solvothermal method. Furthermore, the as-prepared *crystals excitonic recombination lifetime under different pumping energy density was studied by time-resolved photoiuminescence (TRPL). Based on controllable morphology and remarkable lasing properties, these cuboid shaped single crystal perovskite could be a promising candidate for small laser, and other optoelectronic devices.
