钙钛矿材料由于具有结构稳定、易于获取、成本低廉和易于合成等优点,在发光二极管、激光器和太阳能电池等光电器件领域具有广阔的应用前景。目前,部分适合UV-LED应用的钙钛矿具有结构不稳定性。为了寻找结构稳定的钙钛矿,此项研究利用...钙钛矿材料由于具有结构稳定、易于获取、成本低廉和易于合成等优点,在发光二极管、激光器和太阳能电池等光电器件领域具有广阔的应用前景。目前,部分适合UV-LED应用的钙钛矿具有结构不稳定性。为了寻找结构稳定的钙钛矿,此项研究利用第一性原理对无铅双钙钛矿Cs_(2)NaScX_(6)(X=Cl,Br,I)的电子及光学性质进行了理论计算。计算结果表明:Cs_(2)NaScX_(6)(X=Cl,Br,I)为直接带隙半导体,带隙值分别为5.545 e V(Cl)、4.549 eV(Br)和3.408 eV(I),Cs_(2)NaScI_(6)在紫外光范围内具有较强的光吸收。本研究内容为无铅A_(2)B^(I)B^(III)X_(6)型双钙钛矿成为UV-LED的候选材料提供理论支持。展开更多
Inorganic Cs_(2)SnI_(6) perovskite has exhibited substantial potential for light harvesting due to its exceptional optoelectronic properties and remarkable stability in ambient conditions.The charge transport characte...Inorganic Cs_(2)SnI_(6) perovskite has exhibited substantial potential for light harvesting due to its exceptional optoelectronic properties and remarkable stability in ambient conditions.The charge transport characteristics within perovskite films are subject to modulation by various factors,including crystalline orientation,morphology,and crystalline quality.Achieving preferred crystalline orientation and film morphology via a solution-based process is challenging for Cs_(2)SnI_(6) films.In this work,we employed thiourea as an additive to optimize crystal orientation,enhance film morphology,promote crystallization,and achieve phase purity.Thiourea lowers the surface energy of the(222)plane along the(111)direction,confirmed by x-ray diffraction,x-ray photoelectron spectroscopy,ultraviolet photoelectron spectroscopy studies,and density functional theory calculations.Varying thiourea concentration enables a bandgap tuning of Cs_(2)SnI_(6) from 1.52 eV to1.07 eV.This approach provides a novel method for utilizing Cs_(2)SnI_(6) films in high-performance optoelectronic devices.展开更多
In this manuscript,Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites was fabricated via an ultrasonic-assisted process.The activity of the as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites for photocatalytic CO_(2) ...In this manuscript,Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites was fabricated via an ultrasonic-assisted process.The activity of the as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites for photocatalytic CO_(2) reduction was studied under visible light.The as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites show a superior activity for photocatalytic CO_(2) reduction to produce CH4 and CO,with an optimum activity achieved over 0.5 Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6).The obvious superior activity observed over Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites as compared with bare Cs_(2)AgBiBr_(6) and bare Bi_(2)WO_(6) as well as a mechanical mixture of Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6) can be owe to the fabrication of an efficient S-scheme heterojunction,which accelerates the separation of the photogenerated charge carriers in Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6) without sacrificing the high redox capability of Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6).This work demonstrates that the coupling of two photocatalytic materials with staggered band alignment to form an S-scheme heterojunction is an effective strategy to develop efficient photocatalytic systems and also highlights the promising role of using lead free perovskites in photocatalysis.展开更多
Multifunctional lead-free double perovskites demonstrate remarkable potential towards applications in various fields.Herein,an environmentally-friendly,low-cost,high-throughput Cs_(2)NaFeCl_(6) single crystal with exc...Multifunctional lead-free double perovskites demonstrate remarkable potential towards applications in various fields.Herein,an environmentally-friendly,low-cost,high-throughput Cs_(2)NaFeCl_(6) single crystal with exceedingly high thermal stability is designed and grown.It obtains a cubic lattice system in the temperature range of 80-500 K,accompanied by a completely reversible chromatic variation ranging from yellow to black.Importantly,the intriguing thermochromism is proved to own extremely high reproducibility(over 1000 cycles)without a hysteretic effect,originating from its structural flexibility that including(i)the noteworthy distortion/deformation of[NaCl_(6)]5−and[FeCl_(6)]3−octahedra;(ii)order-disorder arrangement transition of[NaCl_(6)]5−and[FeCl6]3−octahedra as the function of temperature.This study paves the way towards a new class of smart windows and camouflage coatings with an unprecedented colour range based on a Cs_(2)NaFeCl_(6) perovskite.展开更多
文摘钙钛矿材料由于具有结构稳定、易于获取、成本低廉和易于合成等优点,在发光二极管、激光器和太阳能电池等光电器件领域具有广阔的应用前景。目前,部分适合UV-LED应用的钙钛矿具有结构不稳定性。为了寻找结构稳定的钙钛矿,此项研究利用第一性原理对无铅双钙钛矿Cs_(2)NaScX_(6)(X=Cl,Br,I)的电子及光学性质进行了理论计算。计算结果表明:Cs_(2)NaScX_(6)(X=Cl,Br,I)为直接带隙半导体,带隙值分别为5.545 e V(Cl)、4.549 eV(Br)和3.408 eV(I),Cs_(2)NaScI_(6)在紫外光范围内具有较强的光吸收。本研究内容为无铅A_(2)B^(I)B^(III)X_(6)型双钙钛矿成为UV-LED的候选材料提供理论支持。
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12174275,62174113,61874139,61904201,and 11875088)Guangdong Basic and Applied Basic Research Foundation (Grant No.2019B1515120057)。
文摘Inorganic Cs_(2)SnI_(6) perovskite has exhibited substantial potential for light harvesting due to its exceptional optoelectronic properties and remarkable stability in ambient conditions.The charge transport characteristics within perovskite films are subject to modulation by various factors,including crystalline orientation,morphology,and crystalline quality.Achieving preferred crystalline orientation and film morphology via a solution-based process is challenging for Cs_(2)SnI_(6) films.In this work,we employed thiourea as an additive to optimize crystal orientation,enhance film morphology,promote crystallization,and achieve phase purity.Thiourea lowers the surface energy of the(222)plane along the(111)direction,confirmed by x-ray diffraction,x-ray photoelectron spectroscopy,ultraviolet photoelectron spectroscopy studies,and density functional theory calculations.Varying thiourea concentration enables a bandgap tuning of Cs_(2)SnI_(6) from 1.52 eV to1.07 eV.This approach provides a novel method for utilizing Cs_(2)SnI_(6) films in high-performance optoelectronic devices.
文摘In this manuscript,Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites was fabricated via an ultrasonic-assisted process.The activity of the as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites for photocatalytic CO_(2) reduction was studied under visible light.The as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites show a superior activity for photocatalytic CO_(2) reduction to produce CH4 and CO,with an optimum activity achieved over 0.5 Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6).The obvious superior activity observed over Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites as compared with bare Cs_(2)AgBiBr_(6) and bare Bi_(2)WO_(6) as well as a mechanical mixture of Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6) can be owe to the fabrication of an efficient S-scheme heterojunction,which accelerates the separation of the photogenerated charge carriers in Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6) without sacrificing the high redox capability of Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6).This work demonstrates that the coupling of two photocatalytic materials with staggered band alignment to form an S-scheme heterojunction is an effective strategy to develop efficient photocatalytic systems and also highlights the promising role of using lead free perovskites in photocatalysis.
基金The research was funded by the National Natural Science Foundation of China(No.51802120,51872126,22075103,51672111)Guangdong Basic and Applied Basic Research Foundation for Distinguished Young Scholar(No.2019B151502030)+7 种基金Natural Science Foundation of Guangdong Province(No.2018030310181)the Science and Technology Plan Project of Guangzhou(No.202002030159)Guangdong Basic and Applied Basic Research Foundation for Young Scholar(No.2020A1515111057)‘100 Talents Program of Hebei Province’(No.E2014100008)the Fundamental Research Funds for the Central Universities(No.21619406)X.Y.thanks for the Special Funds for the Cultivation of Guangdong College Students'Scientific and Technological Innovation("Climbing Program"Special Funds)(No.pdjh2019a0055)J.Fan also thanks for the project support for"Young Top talents"in the Pearl River Talent Project of Guangdong Province(2017GC010424)the Guangdong Provincial Innovation and Entrepreneurship Project(grant 2016ZT06D081).
文摘Multifunctional lead-free double perovskites demonstrate remarkable potential towards applications in various fields.Herein,an environmentally-friendly,low-cost,high-throughput Cs_(2)NaFeCl_(6) single crystal with exceedingly high thermal stability is designed and grown.It obtains a cubic lattice system in the temperature range of 80-500 K,accompanied by a completely reversible chromatic variation ranging from yellow to black.Importantly,the intriguing thermochromism is proved to own extremely high reproducibility(over 1000 cycles)without a hysteretic effect,originating from its structural flexibility that including(i)the noteworthy distortion/deformation of[NaCl_(6)]5−and[FeCl_(6)]3−octahedra;(ii)order-disorder arrangement transition of[NaCl_(6)]5−and[FeCl6]3−octahedra as the function of temperature.This study paves the way towards a new class of smart windows and camouflage coatings with an unprecedented colour range based on a Cs_(2)NaFeCl_(6) perovskite.
