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Chen Y, Yu K, Yan Y, Wang GP. Quantitative Complex Refractive Index Changes in Thin Films: A Pump-Probe Spectroscopy Analysis Approach. J Phys Chem Lett 2024; 15:6467-6475. [PMID: 38869188 DOI: 10.1021/acs.jpclett.4c01249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Photoexcitation induces intricate changes in both the real and imaginary components of the complex refractive index of thin film materials, which is essential for interpreting transient spectral features. Here, we employ a Kramers-Kronig-based analytical approach to elucidate light-induced changes in the complex refractive index from transient transmission spectra of thin films. Using gold-perovskite films as model systems, we conduct experimental measurements of transient transmission spectra for both individual gold and perovskite films, as well as for the bilayer heterostructure. Our analysis reveals significant changes in the refractive index and absorption for these systems. Notably, we observe negligible photocarrier transfer between the gold and perovskite layers based on transient spectroscopic analysis. These findings have implications for the design and optimization of bilayer heterostructures in optoelectronic applications. This work highlights the importance of spectroscopic techniques in studying the photophysical properties of heterostructure films.
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Affiliation(s)
- Yungao Chen
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
| | - Kuai Yu
- State Key Laboratory of Radio Frequency Heterogeneous Integration, College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, China
| | - Yongli Yan
- Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Guo Ping Wang
- State Key Laboratory of Radio Frequency Heterogeneous Integration, College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, China
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2
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Pasanen H, Khan R, Odutola JA, Tkachenko NV. Transient Absorption Spectroscopy of Films: Impact of Refractive Index. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:6167-6179. [PMID: 38655057 PMCID: PMC11037419 DOI: 10.1021/acs.jpcc.4c00981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/19/2024] [Accepted: 03/21/2024] [Indexed: 04/26/2024]
Abstract
Transient absorption spectroscopy is a powerful technique to study the photoinduced phenomena in a wide range of states from solutions to solid film samples. It was designed and developed based on photoinduced absorption changes or that photoexcitation triggers a chain of reactions with intermediate states or reaction steps with presumably different absorption spectra. However, according to general electromagnetic theory, any change in the absorption properties of a medium is accompanied by a change in the refractive properties. Although this photoinduced change in refractive index has a negligible effect on solution measurements, it may significantly affect the measured response of thin films. In this Perspective paper, we examine why and how the measured responses of films differ from their expected "pure" absorption responses. The effect of photoinduced refractive index change can be concluded and studied by comparing the transmitted and reflected probe light responses. Another discussed aspect is the effect of light interference on thin films. Finally, new opportunities of monitoring the photocarrier migration in films and studying nontransparent samples using the reflected probe light response are discussed. Most of the examples provided in this article focus on studies involving perovskite, TiO2, and graphene-based films, but the general discussion and conclusions can be applicable to a wide range of semiconductor and thin metallic films.
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Affiliation(s)
- Hannu
P. Pasanen
- Ultrafast
Dynamics Group Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 4700, Kingdom of Saudi Arabia
| | - Ramsha Khan
- Chemistry
and Advanced Materials Group Faculty of Engineering and Natural Sciences, Tampere University, Tampere 33014, Finland
| | - Jokotadeola A. Odutola
- Chemistry
and Advanced Materials Group Faculty of Engineering and Natural Sciences, Tampere University, Tampere 33014, Finland
| | - Nikolai V. Tkachenko
- Chemistry
and Advanced Materials Group Faculty of Engineering and Natural Sciences, Tampere University, Tampere 33014, Finland
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3
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van der Geest MLS, de Boer JJ, Murzyn K, Jürgens P, Ehrler B, Kraus PM. Transient High-Harmonic Spectroscopy in an Inorganic-Organic Lead Halide Perovskite. J Phys Chem Lett 2023; 14:10810-10818. [PMID: 38015825 DOI: 10.1021/acs.jpclett.3c02588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
High-harmonic generation is the frequency upconversion of an intense femtosecond infrared laser in a material. In condensed-phase high-harmonic generation, laser-driven currents of coherently excited charge carriers map the electronic structure onto the emitted light. This promises a thus far scarcely explored potential of condensed-phase time-resolved high-harmonic spectroscopy for probing carrier dynamics. Here, we realize this potential and use time-resolved solid-state high-harmonic spectroscopy from a laser-excited methylammonium lead bromide (MAPbBr3) thin film, a key material in perovskite solar cells, for measuring carrier cooling and relaxation on femto- and picosecond time scales. Through comparison with transient absorption, we show the links between carrier dynamics and experimental observables of generated harmonics. By highlighting and understanding the interplay of these dynamics, we demonstrate transient optical control over the emission of solid-state high-harmonic generation in MAPbBr3.
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Affiliation(s)
- Maarten L S van der Geest
- Advanced Research Center for Nanolithography (ARCNL), Science Park 106, 1098 XG Amsterdam, The Netherlands
| | - Jeroen J de Boer
- Center for Nanophotonics, AMOLF, Science Park 102, 1098 XG Amsterdam, The Netherlands
| | - Kevin Murzyn
- Advanced Research Center for Nanolithography (ARCNL), Science Park 106, 1098 XG Amsterdam, The Netherlands
| | - Peter Jürgens
- Advanced Research Center for Nanolithography (ARCNL), Science Park 106, 1098 XG Amsterdam, The Netherlands
- Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy, D-12 489 Berlin, Germany
| | - Bruno Ehrler
- Center for Nanophotonics, AMOLF, Science Park 102, 1098 XG Amsterdam, The Netherlands
| | - Peter M Kraus
- Advanced Research Center for Nanolithography (ARCNL), Science Park 106, 1098 XG Amsterdam, The Netherlands
- Department of Physics and Astronomy, and LaserLaB, Vrije Universiteit, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
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Ashoka A, Gauriot N, Girija AV, Sawhney N, Sneyd AJ, Watanabe K, Taniguchi T, Sung J, Schnedermann C, Rao A. Direct observation of ultrafast singlet exciton fission in three dimensions. Nat Commun 2022; 13:5963. [PMID: 36216826 PMCID: PMC9551063 DOI: 10.1038/s41467-022-33647-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 09/26/2022] [Indexed: 11/06/2022] Open
Abstract
We present quantitative ultrafast interferometric pump-probe microscopy capable of tracking of photoexcitations with sub-10 nm spatial precision in three dimensions with 15 fs temporal resolution, through retrieval of the full transient photoinduced complex refractive index. We use this methodology to study the spatiotemporal dynamics of the quantum coherent photophysical process of ultrafast singlet exciton fission. Measurements on microcrystalline pentacene films grown on glass (SiO2) and boron nitride (hBN) reveal a 25 nm, 70 fs expansion of the joint-density-of-states along the crystal a,c-axes accompanied by a 6 nm, 115 fs change in the exciton density along the crystal b-axis. We propose that photogenerated singlet excitons expand along the direction of maximal orbital π-overlap in the crystal a,c-plane to form correlated triplet pairs, which subsequently electronically decouples into free triplets along the crystal b-axis due to molecular sliding motion of neighbouring pentacene molecules. Our methodology lays the foundation for the study of three dimensional transport on ultrafast timescales.
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Affiliation(s)
- Arjun Ashoka
- grid.5335.00000000121885934Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE UK
| | - Nicolas Gauriot
- grid.5335.00000000121885934Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE UK
| | - Aswathy V. Girija
- grid.5335.00000000121885934Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE UK
| | - Nipun Sawhney
- grid.5335.00000000121885934Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE UK
| | - Alexander J. Sneyd
- grid.5335.00000000121885934Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE UK
| | - Kenji Watanabe
- grid.21941.3f0000 0001 0789 6880Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - Takashi Taniguchi
- grid.21941.3f0000 0001 0789 6880International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - Jooyoung Sung
- grid.417736.00000 0004 0438 6721Department of Emerging Materials Science, DGIST, Daegu, 42988 Republic of Korea
| | - Christoph Schnedermann
- grid.5335.00000000121885934Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE UK
| | - Akshay Rao
- grid.5335.00000000121885934Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE UK
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Chen BH, Huang HW, Ye RS, Lu CH, Chen K, Yang SD. Vortex beam assisted energy up-scaling for multiple-plate compression with a single spiral phase plate. OPTICS LETTERS 2022; 47:4423-4426. [PMID: 36048669 DOI: 10.1364/ol.465661] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
The vortex beam (Laguerre-Gaussian, LG10 mode) is employed to alleviate crystal damage in multiple-plate continuum generation. We successfully compressed 190-fs, 1030-nm pulses to 42 fs with 590 μJ input pulse energy, which is 5.5 times higher than that obtained by a Gaussian beam setup of the same footprint. High throughput (86%) and high intensity-weighted beam homogeneity (>98%) have also been achieved. This experiment confirms the great potential of beam shaping in energy up-scaling of nonlinear pulse compression.
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Schirato A, Crotti G, Gonçalves Silva M, Teles-Ferreira DC, Manzoni C, Proietti Zaccaria R, Laporta P, de Paula AM, Cerullo G, Della Valle G. Ultrafast Plasmonics Beyond the Perturbative Regime: Breaking the Electronic-Optical Dynamics Correspondence. NANO LETTERS 2022; 22:2748-2754. [PMID: 35343692 PMCID: PMC9011396 DOI: 10.1021/acs.nanolett.1c04608] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/13/2022] [Indexed: 06/14/2023]
Abstract
The transient optical response of plasmonic nanostructures has recently been the focus of extensive research. Accurate prediction of the ultrafast dynamics following excitation of hot electrons by ultrashort laser pulses is of major relevance in a variety of contexts from the study of light harvesting and photocatalytic processes to nonlinear nanophotonics and the all-optical modulation of light. So far, all studies have assumed the correspondence between the temporal evolution of the dynamic optical signal, retrieved by transient absorption spectroscopy, and that of the photoexcited hot electrons, described in terms of their temperature. Here, we show both theoretically and experimentally that this correspondence does not hold under a nonperturbative excitation regime. Our results indicate that the main mechanism responsible for the breaking of the correspondence between electronic and optical dynamics is universal in plasmonics, being dominated by the nonlinear smearing of the Fermi-Dirac occupation probability at high hot-electron temperatures.
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Affiliation(s)
- Andrea Schirato
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
- Istituto
Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy
| | - Giulia Crotti
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
- Istituto
Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy
| | - Mychel Gonçalves Silva
- Departamento
de Física, Universidade Federal de
Minas Gerais, 31270-901 Belo Horizonte, MG Brazil
| | | | - Cristian Manzoni
- Istituto
di Fotonica e Nanotecnologie - Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
| | - Remo Proietti Zaccaria
- Istituto
Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy
- Cixi Institute
of Biomedical Engineering, Ningbo Institute of Industrial Technology, Chinese Academy of Sciences, 1219 Zhongguan West Road, Ningbo 315201, China
| | - Paolo Laporta
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
- Istituto
di Fotonica e Nanotecnologie - Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
| | - Ana Maria de Paula
- Departamento
de Física, Universidade Federal de
Minas Gerais, 31270-901 Belo Horizonte, MG Brazil
| | - Giulio Cerullo
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
- Istituto
di Fotonica e Nanotecnologie - Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
| | - Giuseppe Della Valle
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
- Istituto
di Fotonica e Nanotecnologie - Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci, 32, I-20133 Milano, Italy
- Istituto
Nazionale di Fisica Nucleare - Sezione di Milano, Via Celoria, 16, I-20133 Milano, Italy
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