The 2D/3D heterojunction perovskites have garnered increasing attention due to their exceptional moisture and thermal stability.However,few works have paid attention to the influence of the subsequent change process o...The 2D/3D heterojunction perovskites have garnered increasing attention due to their exceptional moisture and thermal stability.However,few works have paid attention to the influence of the subsequent change process of 2D/3D heterojunction PSC on the stability of PSCs.Moreover,the evolution of the interface and carrier dynamic behavior of the 2D/3D perovskite films with long-term operation has not been systematically developed befo re.In this work,the effects of 2D/3 D heterojunction evolution on the interface of perovskite films and different carrier dynamics during 2D/3D evolution are systematically analyzed for the first time.The decomposition of 2D/3D heterojunction in the perovskite film will have a certain impact on the surface and carrier dynamics behavior of perovskite.During the evolution of 2D/3D heterojunction,PbI_(2)crystals will appear,which will improve the interfacial energy level matching between the electron transport layer and perovskite film.With a long evolution time,some holes will appear on the surface of perovskite film.The open circuit voltage(V_(OC))of PSCs increased from 1.14 to1.18 V and the PCE increased to 23.21%after 300 h storage in the nitrogen atmosphere,and maintained 89%initial performance for with 3000 h stability test in N_(2)box.This discovery has a significant role in promoting the development of inverted heterojunction PSCs and constructing the revolution mechanism of charge carrier dynamic.展开更多
Organic-inorganic hybrid perovskite solar cells achieve remarkable efficiencies(>26%)yet face stability challenges.Quasi-2D alternating-cation-interlayer perovskites offer enhanced stability through hydrophobic spa...Organic-inorganic hybrid perovskite solar cells achieve remarkable efficiencies(>26%)yet face stability challenges.Quasi-2D alternating-cation-interlayer perovskites offer enhanced stability through hydrophobic spacer cations but suffer from vertical phase segregation and buried interface defects.Herein,we introduce dicyanodiamide(DCD)to simultaneously address these dual limitations in GA(MA)_(n)Pb_(n)I_(3n+1)perovskites.The guanidine group in DCD passivates undercoordinated Pb^(2+)and MA^(+)vacancies at the perovskite/TiO_(2)interface,while cyano groups eliminate oxygen vacancies in TiO_(2)via Ti^(4+)-CN coordination,reducing interfacial trap density by 73%with respect to the control sample.In addition,DCD regulates crystallization kinetics,suppressing low-n-phase aggregation and promoting vertical alignment of high-n phases,which benefit for carrier transport.This dual-functional modification enhances charge transport and stabilizes energy-level alignment.The optimized devices achieve a record power conversion efficiency of 21.54%(vs.19.05%control)and retain 94%initial efficiency after 1200 h,outperforming unmodified counterparts(84%retention).Combining defect passivation with phase homogenization,this work establishes a molecular bridge strategy to decouple stability-efficiency trade-offs in low-dimensional perovskites,providing a universal framework for interface engineering in high-performance optoelectronics.展开更多
Large-area two-dimensional(2D)materials,such as graphene,MoS_(2),WS_(2),h-BN,black phosphorus,and MXenes,are a class of advanced materials with many possible applications.Different applications need different substrat...Large-area two-dimensional(2D)materials,such as graphene,MoS_(2),WS_(2),h-BN,black phosphorus,and MXenes,are a class of advanced materials with many possible applications.Different applications need different substrates,and each substrate may need a different way of transferring the 2D material onto it.Problems such as local stress concentrations,an uneven surface tension,inconsistent adhesion,mechanical damage and contamination during the transfer can adversely affect the quality and properties of the transferred material.Therefore,how to improve the integrity,flatness and cleanness of large area 2D materials is a challenge.In order to achieve high-quality transfer,the main concern is to control the interface adhesion between the substrate,the 2D material and the transfer medium.This review focuses on this topic,and finally,in order to promote the industrial use of large area 2D materials,provides a recipe for this transfer process based on the requirements of the application,and points out the current problems and directions for future development.展开更多
Photocatalytic CO_(2)reduction into value-added chemicals holds significant promise for carbon-neutral recycling and solar-to-fuel conversion.Enhancing reaction efficiency by manipulating charge transfer is a key appr...Photocatalytic CO_(2)reduction into value-added chemicals holds significant promise for carbon-neutral recycling and solar-to-fuel conversion.Enhancing reaction efficiency by manipulating charge transfer is a key approach to unlocking this potential.In this work,we construct a two-dimensional/twodimensional(2D/2D)FeSe_(2)/protonated carbon nitride(FeSe_(2)/PCN)heterostructure to promote the interfacial charge transfer dynamics,leading to a four-fold improved conversion efficiency of photocatalytic CO_(2)reduction with near 100%CO selectivity.Combining in situ X-ray photoelectron spectroscopy,in situ soft X-ray absorption spectroscopy,and femtosecond transient absorption spectroscopy,it is revealed that FeSe_(2)acts as an electron acceptor upon photoexcitation,introducing an additional electron transfer pathway from PCN to FeSe_(2)that suppresses radiative recombination and promotes charge transfer.In situ X-ray absorption fine structure spectroscopy,in situ diffuse reflectance infrared Fourier transform spectroscopy,and density functional theory calculation further unravel that the electron-enriched FeSe_(2)functions as the active sites for CO_(2)activation and significantly reduces the energy barrier of key intermediate COOH*formation,which is the rate-determined step for CO generation.This work underscores the importance of regulating photocarrier relaxation pathways to achieve effective spatial charge separation for promoted photocatalytic CO_(2)reduction and demonstrates the powerful functions of in situ spectroscopies in in-depth understanding of the photocatalytic mechanism.展开更多
开发了一种使用直写成型(DIW)3D打印方法制备多孔TiO_(2)光催化降解筛的成型技术,厘清了打印浆料中P25粉末、TiO_(2)前驱体溶胶和聚乙烯醇(PVA)含量对其成型性能的影响规律;进一步研究了降解筛的物相组成、微观形貌、能带结构和载流子寿...开发了一种使用直写成型(DIW)3D打印方法制备多孔TiO_(2)光催化降解筛的成型技术,厘清了打印浆料中P25粉末、TiO_(2)前驱体溶胶和聚乙烯醇(PVA)含量对其成型性能的影响规律;进一步研究了降解筛的物相组成、微观形貌、能带结构和载流子寿命,并在模拟自然光下测定了其对盐酸四环素(TC)的光催化降解性能和循环稳定性.结果表明:TiO_(2)前驱体溶胶起到了分散P25颗粒和稳定浆料的作用,而PVA的加入则进一步改善了浆料的流变性能.当使用9 g P25粉末与10 mL TiO_(2)前驱体溶胶和1 mL质量分数为7%的PVA溶液混合时,得到了具有最佳成型性能的打印浆料,制备的降解筛结构完整,无塌陷和开裂.热处理后TiO_(2)前驱体溶胶转化而来的小粒径TiO_(2)填充在P25颗粒之间,起到了增强机械强度的作用,而PVA作为造孔剂极大地丰富了降解筛的孔隙结构.TiO_(2)光催化降解筛对TC表现出优异的光催化性能和循环稳定性,140 min内的降解率为98.4%,并在5次循环之后保持96.0%的降解率.展开更多
传统的功率分配算法由于复杂的矩阵运算与迭代所造成的高时延,在实际通信中实时获取信道信息十分困难,当前重要的研究方向是在系统性能和计算复杂度之间找到有效平衡。针对终端直通(Device-to-Device,D2D)用户与蜂窝用户的联合功率分配...传统的功率分配算法由于复杂的矩阵运算与迭代所造成的高时延,在实际通信中实时获取信道信息十分困难,当前重要的研究方向是在系统性能和计算复杂度之间找到有效平衡。针对终端直通(Device-to-Device,D2D)用户与蜂窝用户的联合功率分配问题,提出一种异构功率控制图神经网络(Heterogeneous Power Control Graph Neural Network,HPCGNN)算法,旨在最大化所有用户的加权和速率。首先通过构建干扰的异构图,将信道和噪声等信息嵌入到图的节点和边;再由HPCGNN完成消息传递和更新,采用无监督学习方式优化深度神经网络(Deep Neural Network,DNN)参数,最终得到最佳的功率分配。仿真结果表明,相较于其他深度学习算法,所提算法能够有效提高系统性能,且在损失5%性能下相较分式规划(Fractional Programming,FP)能降低82%~98%的时间复杂度。展开更多
基金financial support provided by the Sichuan Science and Technology Program(No.2022NSFSC0226)Sichuan Science and Technology Program(No.2023ZYD0163)+6 种基金the Production-Education Integration Demonstration Project of Sichuan Provincethe Photovoltaic Industry Production-Education Integration Comprehensive Demonstration Base of Sichuan Province(Sichuan Financial Education[2022]No.106)China Tianfu Yongxing Laboratory Science and Technology Key Project(2023KJGG15)National Key Research and Development Program of China(2022YFB3803300)Beijing Natural Science Foundation(IS23037)the Department for Energy Security and Net Zero(project ID:NEXTCCUS)the ACT program(Accelerating CCS Technologies,Horizon2020 project NO.691712)。
文摘The 2D/3D heterojunction perovskites have garnered increasing attention due to their exceptional moisture and thermal stability.However,few works have paid attention to the influence of the subsequent change process of 2D/3D heterojunction PSC on the stability of PSCs.Moreover,the evolution of the interface and carrier dynamic behavior of the 2D/3D perovskite films with long-term operation has not been systematically developed befo re.In this work,the effects of 2D/3 D heterojunction evolution on the interface of perovskite films and different carrier dynamics during 2D/3D evolution are systematically analyzed for the first time.The decomposition of 2D/3D heterojunction in the perovskite film will have a certain impact on the surface and carrier dynamics behavior of perovskite.During the evolution of 2D/3D heterojunction,PbI_(2)crystals will appear,which will improve the interfacial energy level matching between the electron transport layer and perovskite film.With a long evolution time,some holes will appear on the surface of perovskite film.The open circuit voltage(V_(OC))of PSCs increased from 1.14 to1.18 V and the PCE increased to 23.21%after 300 h storage in the nitrogen atmosphere,and maintained 89%initial performance for with 3000 h stability test in N_(2)box.This discovery has a significant role in promoting the development of inverted heterojunction PSCs and constructing the revolution mechanism of charge carrier dynamic.
基金support from the National Key R&D Program of China(Grant No.2023YFE0111500)the National Natural Science Foundation of China(Grant No.52321006,T2394480,T2394484,22109143,22479131)+8 种基金Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-202005)the China Postdoctoral Innovative Talent Support Program(Grant No.BX2021271)the China Postdoctoral Science Foundation(2022M712851)the Opening Project of State Key Laboratory of Advanced Technology for Float Glass(Grant No.2022KF04)Graduate Education Reform Project of Henan Province(Grant No.2023SJGLX136Y)Key R&D Special Program of Henan Province(Grant No.241111242000)Program for Science and Technology Innovation Talents in Universities of Henan Province(Grant No.25HASTIT005)Training Plan for Young Backbone Teachers of Zhengzhou University(Grant No.2023ZDGGJS017)the Joint Research Project of Puyang Shengtong Juyuan New Materials Co.,Ltd.(Grant No.20230128A).
文摘Organic-inorganic hybrid perovskite solar cells achieve remarkable efficiencies(>26%)yet face stability challenges.Quasi-2D alternating-cation-interlayer perovskites offer enhanced stability through hydrophobic spacer cations but suffer from vertical phase segregation and buried interface defects.Herein,we introduce dicyanodiamide(DCD)to simultaneously address these dual limitations in GA(MA)_(n)Pb_(n)I_(3n+1)perovskites.The guanidine group in DCD passivates undercoordinated Pb^(2+)and MA^(+)vacancies at the perovskite/TiO_(2)interface,while cyano groups eliminate oxygen vacancies in TiO_(2)via Ti^(4+)-CN coordination,reducing interfacial trap density by 73%with respect to the control sample.In addition,DCD regulates crystallization kinetics,suppressing low-n-phase aggregation and promoting vertical alignment of high-n phases,which benefit for carrier transport.This dual-functional modification enhances charge transport and stabilizes energy-level alignment.The optimized devices achieve a record power conversion efficiency of 21.54%(vs.19.05%control)and retain 94%initial efficiency after 1200 h,outperforming unmodified counterparts(84%retention).Combining defect passivation with phase homogenization,this work establishes a molecular bridge strategy to decouple stability-efficiency trade-offs in low-dimensional perovskites,providing a universal framework for interface engineering in high-performance optoelectronics.
基金the National Key R&D Program of China(2022YFA1505200)the National Natural Science Foundation of China(22472140,22021001)the Fundamental Research Funds for the Central Universities(20720210017 and 20720210009)。
文摘Large-area two-dimensional(2D)materials,such as graphene,MoS_(2),WS_(2),h-BN,black phosphorus,and MXenes,are a class of advanced materials with many possible applications.Different applications need different substrates,and each substrate may need a different way of transferring the 2D material onto it.Problems such as local stress concentrations,an uneven surface tension,inconsistent adhesion,mechanical damage and contamination during the transfer can adversely affect the quality and properties of the transferred material.Therefore,how to improve the integrity,flatness and cleanness of large area 2D materials is a challenge.In order to achieve high-quality transfer,the main concern is to control the interface adhesion between the substrate,the 2D material and the transfer medium.This review focuses on this topic,and finally,in order to promote the industrial use of large area 2D materials,provides a recipe for this transfer process based on the requirements of the application,and points out the current problems and directions for future development.
基金supported by the National Natural Science Foundation of China(12241502,92045301)Fundamental Research Funds for the Central Universities(20720220010)+7 种基金USTC Research Funds of the Double First-Class Initiative(YD2310002012)the Launching Special Funds of Scientific Research for Introduced Talents from University of Science and Technology of China(KY2310000060)National Key Research and Development Program of China(2019YFA0405602)Anhui Provincial Natural Science Foundation(2408085QB049)the Instruments Center for Physical Science and USTC Center for Micro and Nanoscale Research and Fabrication,University of Science and Technology of Chinathe solid supports from the BL03U,BL10B,and BL12B beamlines of the National Synchrotron Radiation Laboratory(NSRL,Hefei)the Shanghai Synchrotron Radiation Facility(SSRF,Shanghai)of BL11B(https://cstr.cn/31124.02.SSRF.BL11B)and BL14W1(https://cstr.cn/31124.02.SSRF.BL14W1)beamlines for the assistance on XAFS measurementsAnhui Chuangpu Instruments Co.,Ltd.for the assistance in the test of Table XAFS。
文摘Photocatalytic CO_(2)reduction into value-added chemicals holds significant promise for carbon-neutral recycling and solar-to-fuel conversion.Enhancing reaction efficiency by manipulating charge transfer is a key approach to unlocking this potential.In this work,we construct a two-dimensional/twodimensional(2D/2D)FeSe_(2)/protonated carbon nitride(FeSe_(2)/PCN)heterostructure to promote the interfacial charge transfer dynamics,leading to a four-fold improved conversion efficiency of photocatalytic CO_(2)reduction with near 100%CO selectivity.Combining in situ X-ray photoelectron spectroscopy,in situ soft X-ray absorption spectroscopy,and femtosecond transient absorption spectroscopy,it is revealed that FeSe_(2)acts as an electron acceptor upon photoexcitation,introducing an additional electron transfer pathway from PCN to FeSe_(2)that suppresses radiative recombination and promotes charge transfer.In situ X-ray absorption fine structure spectroscopy,in situ diffuse reflectance infrared Fourier transform spectroscopy,and density functional theory calculation further unravel that the electron-enriched FeSe_(2)functions as the active sites for CO_(2)activation and significantly reduces the energy barrier of key intermediate COOH*formation,which is the rate-determined step for CO generation.This work underscores the importance of regulating photocarrier relaxation pathways to achieve effective spatial charge separation for promoted photocatalytic CO_(2)reduction and demonstrates the powerful functions of in situ spectroscopies in in-depth understanding of the photocatalytic mechanism.
文摘开发了一种使用直写成型(DIW)3D打印方法制备多孔TiO_(2)光催化降解筛的成型技术,厘清了打印浆料中P25粉末、TiO_(2)前驱体溶胶和聚乙烯醇(PVA)含量对其成型性能的影响规律;进一步研究了降解筛的物相组成、微观形貌、能带结构和载流子寿命,并在模拟自然光下测定了其对盐酸四环素(TC)的光催化降解性能和循环稳定性.结果表明:TiO_(2)前驱体溶胶起到了分散P25颗粒和稳定浆料的作用,而PVA的加入则进一步改善了浆料的流变性能.当使用9 g P25粉末与10 mL TiO_(2)前驱体溶胶和1 mL质量分数为7%的PVA溶液混合时,得到了具有最佳成型性能的打印浆料,制备的降解筛结构完整,无塌陷和开裂.热处理后TiO_(2)前驱体溶胶转化而来的小粒径TiO_(2)填充在P25颗粒之间,起到了增强机械强度的作用,而PVA作为造孔剂极大地丰富了降解筛的孔隙结构.TiO_(2)光催化降解筛对TC表现出优异的光催化性能和循环稳定性,140 min内的降解率为98.4%,并在5次循环之后保持96.0%的降解率.
文摘传统的功率分配算法由于复杂的矩阵运算与迭代所造成的高时延,在实际通信中实时获取信道信息十分困难,当前重要的研究方向是在系统性能和计算复杂度之间找到有效平衡。针对终端直通(Device-to-Device,D2D)用户与蜂窝用户的联合功率分配问题,提出一种异构功率控制图神经网络(Heterogeneous Power Control Graph Neural Network,HPCGNN)算法,旨在最大化所有用户的加权和速率。首先通过构建干扰的异构图,将信道和噪声等信息嵌入到图的节点和边;再由HPCGNN完成消息传递和更新,采用无监督学习方式优化深度神经网络(Deep Neural Network,DNN)参数,最终得到最佳的功率分配。仿真结果表明,相较于其他深度学习算法,所提算法能够有效提高系统性能,且在损失5%性能下相较分式规划(Fractional Programming,FP)能降低82%~98%的时间复杂度。
