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Abstract
Nonlinear optical (NLO) microscopy relies on multiple light-matter interactions to provide unique contrast mechanisms and imaging capabilities that are inaccessible to traditional linear optical imaging approaches, making them versatile tools to understand a wide range of complex systems. However, the strong excitation fields that are necessary to drive higher-order optical processes efficiently are often responsible for photobleaching, photodegradation, and interruption in many systems of interest. This is especially true for imaging living biological samples over prolonged periods of time or in accessing intrinsic dynamics of electronic excited-state processes in spatially heterogeneous materials. This perspective outlines some of the key limitations of two NLO imaging modalities implemented in our lab and highlights the unique potential afforded by the quantum properties of light, especially entangled two-photon absorption based NLO spectroscopy and microscopy. We further review some of the recent exciting advances in this emerging filed and highlight some major challenges facing the realization of quantum-light-enabled NLO imaging modalities.
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Affiliation(s)
- Ying-Zhong Ma
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Benjamin Doughty
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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2
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Doughty B, Simpson MJ, Das S, Xiao K, Ma YZ. Connecting Femtosecond Transient Absorption Microscopy with Spatially Coregistered Time Averaged Optical Imaging Modalities. J Phys Chem A 2020; 124:3915-3923. [PMID: 32309940 DOI: 10.1021/acs.jpca.9b11996] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Multimodal all-optical imaging involving coregistered femtosecond transient absorption microscopy (TAM), time-integrated photoluminescence (PL), and steady-state modalities such as confocal reflectance and transmission offers an appealing approach to gain a comprehensive understanding of complex electronic excited-state phenomena in spatially heterogeneous systems. A unique combination of these modalities allows us to unravel not only the competing electronic excited-state dynamical processes but also the underlying morphological information with simultaneous high temporal and spatial resolution. However, correlating the various images obtained from time-resolved and time-independent modalities is generally nontrivial and particularly challenging when the electronic dynamics under study evolve in both time and space. Here, we demonstrate a new approach for rationally correlating time-resolved microscopy with coregistered time-integrated or steady-state modalities. Specifically, our approach involves an extended global lifetime analysis of the time-resolved microscopic data set to separate distinct dynamical processes taking place on commensurate time scales, and the resulting decay-associated amplitude maps (DAAMs) were applied to explore correlations with the images acquired using time-independent modalities. The feasibility of our approach was validated through analyzing a multimodal data set acquired from a thin film of chloride-containing mixed lead halide perovskites (CH3NH3PbI3-xClx) using femtosecond transient absorption, time-integrated PL, and confocal reflectance microscopies. Analysis of the results obtained enable us to gain new insight into the complex ultrafast relaxation dynamics in this highly heterogeneous system.
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Affiliation(s)
- Benjamin Doughty
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Mary Jane Simpson
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sanjib Das
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ying-Zhong Ma
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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3
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O'Keeffe P, Catone D, Paladini A, Toschi F, Turchini S, Avaldi L, Martelli F, Agresti A, Pescetelli S, Del Rio Castillo AE, Bonaccorso F, Di Carlo A. Graphene-Induced Improvements of Perovskite Solar Cell Stability: Effects on Hot-Carriers. NANO LETTERS 2019; 19:684-691. [PMID: 30669832 DOI: 10.1021/acs.nanolett.8b03685] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hot-carriers, that is, charge carriers with an effective temperature higher than that of the lattice, may contribute to the high power conversion efficiency (PCE) shown by perovskite-based solar cells (PSCs), which are now competitive with silicon solar cells. Hot-carriers lose their excess energy in very short times, typically in a few picoseconds after excitation. For this reason, the carrier dynamics occurring on this time scale are extremely important in determining the participation of hot-carriers in the photovoltaic process. However, the stability of PSCs over time still remains an issue that calls for a solution. In this work, we demonstrate that the insertion of graphene flakes into the mesoscopic TiO2 scaffold leads to stable values of carrier temperature. In PSCs aged over 1 week, we indeed observe that in the graphene-free perovskite cells the carrier temperature decreases by about 500 K from 1800 to 1300 K, while the graphene-containing cell shows a reduction of less than 200 K after the same aging time delay. The stability of the carrier temperature reflects the stability of the perovskite nanocrystals embedded in the mesoporous graphene-TiO2 layer. Our results, based on femtosecond transient absorption measurements, show that the insertion of graphene can be beneficial for the design of stable PSCs with the aim of exploiting the hot-carrier contribution to the PCE of the PSCs.
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Affiliation(s)
- P O'Keeffe
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) , Area della Ricerca di Roma 1 , Monterotondo Scalo , Italy
| | - D Catone
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) , Area della Ricerca di Roma Tor Vergata , Via del Fosso del Cavaliere 100 , 00133 Rome , Italy
| | - A Paladini
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) , Area della Ricerca di Roma 1 , Monterotondo Scalo , Italy
| | - F Toschi
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) , Area della Ricerca di Roma 1 , Monterotondo Scalo , Italy
| | - S Turchini
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) , Area della Ricerca di Roma Tor Vergata , Via del Fosso del Cavaliere 100 , 00133 Rome , Italy
| | - L Avaldi
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) , Area della Ricerca di Roma 1 , Monterotondo Scalo , Italy
| | - F Martelli
- CNR-IMM, Area della Ricerca di Roma Tor Vergata , 100 Via del Fosso del Cavaliere , 00133 Rome , Italy
| | - A Agresti
- CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering , University of Rome Tor Vergata , Via del Politecnico 1 , 00133 Rome , Italy
| | - S Pescetelli
- CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering , University of Rome Tor Vergata , Via del Politecnico 1 , 00133 Rome , Italy
| | - A E Del Rio Castillo
- Graphene Laboratories , IIT - Istituto Italiano di Tecnologia , Via Morego 30 , 16163 Genova , Italy
| | - F Bonaccorso
- Graphene Laboratories , IIT - Istituto Italiano di Tecnologia , Via Morego 30 , 16163 Genova , Italy
- BeDimensional Spa , Via Albisola 121 , 16163 Genova , Italy
| | - A Di Carlo
- CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering , University of Rome Tor Vergata , Via del Politecnico 1 , 00133 Rome , Italy
- LASE - Laboratory for Advanced Solar Energy , National University of Science and Technology MISiS , Leninsky Ave. 6 , 119049 Moscow , Russia
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Belianinov A, Ievlev AV, Lorenz M, Borodinov N, Doughty B, Kalinin SV, Fernández FM, Ovchinnikova OS. Correlated Materials Characterization via Multimodal Chemical and Functional Imaging. ACS NANO 2018; 12:11798-11818. [PMID: 30422627 PMCID: PMC9850281 DOI: 10.1021/acsnano.8b07292] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Multimodal chemical imaging simultaneously offers high-resolution chemical and physical information with nanoscale and, in select cases, atomic resolution. By coupling modalities that collect physical and chemical information, we can address scientific problems in biological systems, battery and fuel cell research, catalysis, pharmaceuticals, photovoltaics, medicine, and many others. The combined systems enable the local correlation of material properties with chemical makeup, making fundamental questions of how chemistry and structure drive functionality approachable. In this Review, we present recent progress and offer a perspective for chemical imaging used to characterize a variety of samples by a number of platforms. Specifically, we present cases of infrared and Raman spectroscopies combined with scanning probe microscopy; optical microscopy and mass spectrometry; nonlinear optical microscopy; and, finally, ion, electron, and probe microscopies with mass spectrometry. We also discuss the challenges associated with the use of data originated by the combinatorial hardware, analysis, and machine learning as well as processing tools necessary for the interpretation of multidimensional data acquired from multimodal studies.
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Affiliation(s)
- Alex Belianinov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Anton V. Ievlev
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Matthias Lorenz
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Nikolay Borodinov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Benjamin Doughty
- Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sergei V. Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Facundo M. Fernández
- School of Chemistry and Biochemistry, Georgia Institute of Technology and Petit Institute for Biochemistry and Bioscience, Atlanta, Georgia 30332, United States
| | - Olga S. Ovchinnikova
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Corresponding Author:
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Simpson MJ, Doughty B, Das S, Xiao K, Ma YZ. Separating Bulk and Surface Contributions to Electronic Excited-State Processes in Hybrid Mixed Perovskite Thin Films via Multimodal All-Optical Imaging. J Phys Chem Lett 2017; 8:3299-3305. [PMID: 28675298 DOI: 10.1021/acs.jpclett.7b01368] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A comprehensive understanding of electronic excited-state phenomena underlying the impressive performance of solution-processed hybrid halide perovskite solar cells requires access to both spatially resolved electronic processes and corresponding sample morphological characteristics. Here, we demonstrate an all-optical multimodal imaging approach that enables us to obtain both electronic excited-state and morphological information on a single optical microscope platform with simultaneous high temporal and spatial resolution. Specifically, images were acquired for the same region of interest in thin films of chloride containing mixed lead halide perovskites (CH3NH3PbI3-xClx) using femtosecond transient absorption, time-integrated photoluminescence, confocal reflectance, and transmission microscopies. Comprehensive image analysis revealed the presence of surface- and bulk-dominated contributions to the various images, which describe either spatially dependent electronic excited-state properties or morphological variations across the probed region of the thin films. These results show that PL probes effectively the species near or at the film surface.
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Affiliation(s)
- Mary Jane Simpson
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Benjamin Doughty
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Sanjib Das
- Department of Electrical Engineering and Computer Science, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Ying-Zhong Ma
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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Simpson MJ, Doughty B, Yang B, Xiao K, Ma YZ. Imaging Electronic Trap States in Perovskite Thin Films with Combined Fluorescence and Femtosecond Transient Absorption Microscopy. J Phys Chem Lett 2016; 7:1725-31. [PMID: 27103096 DOI: 10.1021/acs.jpclett.6b00715] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Charge carrier trapping degrades the performance of organometallic halide perovskite solar cells. To characterize the locations of electronic trap states in a heterogeneous photoactive layer, a spatially resolved approach is essential. Here, we report a comparative study on methylammonium lead tri-iodide perovskite thin films subject to different thermal annealing times using a combined photoluminescence (PL) and femtosecond transient absorption microscopy (TAM) approach to spatially map trap states. This approach coregisters the initially populated electronic excited states with the regions that recombine radiatively. Although the TAM images are relatively homogeneous for both samples, the corresponding PL images are highly structured. The remarkable variation in the PL intensities as compared to transient absorption signal amplitude suggests spatially dependent PL quantum efficiency, indicative of trapping events. Detailed analysis enables identification of two trapping regimes: a densely packed trapping region and a sparse trapping area that appear as unique spatial features in scaled PL maps.
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Affiliation(s)
- Mary Jane Simpson
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Benjamin Doughty
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Bin Yang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Ying-Zhong Ma
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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Yang B, Mahjouri-Samani M, Rouleau CM, Geohegan DB, Xiao K. Low temperature synthesis of hierarchical TiO2 nanostructures for high performance perovskite solar cells by pulsed laser deposition. Phys Chem Chem Phys 2016; 18:27067-27072. [DOI: 10.1039/c6cp02896a] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High aspect-ratio TiO2 nanostructures directly assembled with pulsed laser deposition could improve interfacial contact for superior perovskite photovoltaic cells.
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Affiliation(s)
- Bin Yang
- Center for Nanophase Materials Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | | | | | - David B. Geohegan
- Center for Nanophase Materials Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Kai Xiao
- Center for Nanophase Materials Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
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