Scanning electrochemical cell microscopy(SECCM)is increasingly applied to determine the intrinsic catalytic activity of single electrocatalyst particle.This is especially feasible if the catalyst nanoparticles are lar...Scanning electrochemical cell microscopy(SECCM)is increasingly applied to determine the intrinsic catalytic activity of single electrocatalyst particle.This is especially feasible if the catalyst nanoparticles are large enough that they can be found and counted in post-SECCM scanning electron microscopy images.Evidently,this becomes impossible for very small nanoparticles and hence,a catalytic current measured in one landing zone of the SECCM droplet cannot be correlated to the exact number of catalyst particles.We show,that by introducing a ruler method employing a carbon nanoelectrode decorated with a countable number of the same catalyst particles from which the catalytic activity can be determined,the activity determined using SECCM from many spots can be converted in the intrinsic catalytic activity of a certain number of catalyst nanoparticles.展开更多
Organometallic halide perovskites have garnered significant attention in various fields of material science,particularly solar energy conversion,due to their desirable optoelectronic properties and compatibility with ...Organometallic halide perovskites have garnered significant attention in various fields of material science,particularly solar energy conversion,due to their desirable optoelectronic properties and compatibility with scalable fabrication techniques.It is often unclear,however,how carrier generation and transport within complex polycrystalline films are influenced by variations in local structure.Elucidating how distinct structural motifs within these heterogeneous systems affect behavior could help guide the continued improvement of perovskite-based solar cells.Here,we present studies applying scanning electron microscopy(SECCM)to map solar energy harvesting within well-defined model systems of organometallic halide perovskites.Methylammonium lead bromide(MAPbBr3)single crystals were prepared via a low-temperature solution-based route,and their photoelectrochemical properties were mapped via SECCM using p-benzoquinone(BQ)in dichloromethane as a redox mediator.Correlated SECCM mapping and electron microscopy studies enabled facet-to-facet variations in photoelectrochemical performance to be revealed and carrier transport lengths to be evaluated.The photoelectrochemical behavior observed within individual single crystals was quite heterogeneous,attributable to local variations in crystal structure/orientations,intrafacet junctions,and the presence of other structural defects.These observations underscore the significance of controlling the microstructure of single perovskite crystals,presenting a promising avenue for further enhancement of perovskitebased solar cells.展开更多
基金funding from the European Research Council(ERC)under the European Unions Horizon 2020 research and innovation programme(grant agreement CasCat[833408])well as from the European Unions Horizon 2020 research and innovation program under the Marie Sktodowska-Curie MSCA-ITN Single-Entity Nanoelectrochemistry,Sentinel[812398]+2 种基金S.S.and C.A.acknowledge the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)within the project[440951282]X.X.C.acknowledges financial support from the Liaoning BaiQianWan Talents Program,China(No.2019B042)the Excellent Young Scientific and Technological Talents Project of Educational Department of Liaoning Province,China(No.2020LNQN07).
文摘Scanning electrochemical cell microscopy(SECCM)is increasingly applied to determine the intrinsic catalytic activity of single electrocatalyst particle.This is especially feasible if the catalyst nanoparticles are large enough that they can be found and counted in post-SECCM scanning electron microscopy images.Evidently,this becomes impossible for very small nanoparticles and hence,a catalytic current measured in one landing zone of the SECCM droplet cannot be correlated to the exact number of catalyst particles.We show,that by introducing a ruler method employing a carbon nanoelectrode decorated with a countable number of the same catalyst particles from which the catalytic activity can be determined,the activity determined using SECCM from many spots can be converted in the intrinsic catalytic activity of a certain number of catalyst nanoparticles.
基金support for this work from the National Science Foundation(CHE-2045593)the University of Wyoming School of Energy Resources.
文摘Organometallic halide perovskites have garnered significant attention in various fields of material science,particularly solar energy conversion,due to their desirable optoelectronic properties and compatibility with scalable fabrication techniques.It is often unclear,however,how carrier generation and transport within complex polycrystalline films are influenced by variations in local structure.Elucidating how distinct structural motifs within these heterogeneous systems affect behavior could help guide the continued improvement of perovskite-based solar cells.Here,we present studies applying scanning electron microscopy(SECCM)to map solar energy harvesting within well-defined model systems of organometallic halide perovskites.Methylammonium lead bromide(MAPbBr3)single crystals were prepared via a low-temperature solution-based route,and their photoelectrochemical properties were mapped via SECCM using p-benzoquinone(BQ)in dichloromethane as a redox mediator.Correlated SECCM mapping and electron microscopy studies enabled facet-to-facet variations in photoelectrochemical performance to be revealed and carrier transport lengths to be evaluated.The photoelectrochemical behavior observed within individual single crystals was quite heterogeneous,attributable to local variations in crystal structure/orientations,intrafacet junctions,and the presence of other structural defects.These observations underscore the significance of controlling the microstructure of single perovskite crystals,presenting a promising avenue for further enhancement of perovskitebased solar cells.
