High-Sensitivity Visualization of Ulitrafast Carrier Diffusion by Wide-Field Holographic Microscopy  

作　　者：Martin Hörmann Federico Visentin Andrea Zanetta Johann Osmond Giulia Grancini Niek Fvan Hulst Matz Liebel Giulio Cerullo Franco V.A.Camargo 

机构地区：[1]Dipartimento di Fisica,Politecnico di Milano,Piazza L.da Vinci 32,20133 Milano,Italy [2]Department of Chemistry and INSTM,University of Pavia,Via T.Taramelli 14,27100 Pavia,Italy [3]ICFO-Institut de Ciencies Fotoniques,The Barcelona Institute of Science and Technology,08860 Castelldefels,Barcelona,Spain [4]ICREA-InstitucióCatalana de Recerca i Estudis Avançats,Passeig Lluís Companys 23,08010 Barcelona,Spain [5]IFN-CNR,Piazza L.da Vinci 32,20133 Milano,Italy.

出　　处：《Ultrafast Science》2023年第5期43-49,共7页超快科学（英文）

基　　金：support from the Marie Sktodowska-Curie project 812992-"MUSIQ"F.V.,M.L.,G.C.,and N.F.v.H.acknowledge funding from HORIZONEIC-2021-PATHFINDEROPEN-01 project"TROPHY" (grant agreement no.101047137);G.G.and A.Z.acknowledge the“HY-NANO"project that has received funding from the European Research Council (ERC)Starting Grant 2018 under the European Union's Horizon 2020 research and innovation program (grant agreement no.802862);support from the Ministero dell'Universita e della Ricerca (MUR)and the University of Pavia through the program“Dipartimenti di Eccellenza 2023-2027"M.L.and N.Fv.H.acknowledge support through the RTI2018-099957-J-100 and PGC2018-096875-B-I00 projects funded by MCIN/AEI/10.13039/501100011033/FEDER;the MICINN“Severo Ochoa"program for Centers of Excellence in R&D CEX2019-000910-S;Fundacio Privada Cellex,Fundacio Privada Mir-Puig, and the Generalitat de Catalunya throughthe CERCA program. N.F.v. H. acknowledges the financialsupport by the European Commission (ERC advanced grant670949-LightNet). Competing interests: The authors declarethat they have no competing interests.

摘　　要：Ultrafast transient microscopy is a key tool to study the photophysical properties of materials in space and time,but current implementations are limited to≈1-μm fields of view,offering no statistical information for heterogeneous samples.Recently,we demonstrated wide-field transient imaging based on multiplexed off-axis holography.Here,we perform ultrafast microscopy in parallel around a hundred diffraction-limited excitation spots over a≈60-μm field of view,which not only automatically samples the photophysical heterogeneity of the sample over a large area but can also be used to obtain a 10-fold increase in signal-tonoise ratio by computing an average spot.We apply our microscope to study the carrier diffusion processes in methylammonium lead bromide perovskites.We observe strong diffusion due to the presence of hot carriers during the first picosecond and slower diffusion afterward.We also describe how many-body kinetics can be misleadingly interpreted as strong diffusion at high excitation densities,while at weak excitation,real diffusion is observed.Therefore,the vast increase in sensitivity offered by this technique benefits the study of carrier transport not only by reducing data acquisition times but also by enabling the measurement of the much smaller signals generated at low carrier densities.

关 键 词：DIFFUSION EXCITATION TRANSIENT 

分 类 号：TH742[机械工程—光学工程]