1
|
Rahman MB, Islam A, Iimori T. Exciton Delocalization and Polarizability in Perylenetetracarboxylic Diimide Probed Using Electroabsorption and Fluorescence Spectroscopies. Molecules 2024; 29:2206. [PMID: 38792068 PMCID: PMC11123886 DOI: 10.3390/molecules29102206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 04/24/2024] [Accepted: 04/30/2024] [Indexed: 05/26/2024] Open
Abstract
Perylenetetracarboxylic diimide (PTCDI) is an n-type organic semiconductor molecule that has been widely utilized in numerous applications such as photocatalysis and field-effect transistors. Polarizability and dipole moment, which are inherent properties of molecules, are important parameters that determine their responses to external electric and optical fields, physical properties, and reactivity. These parameters are fundamentally important for the design of innovative materials. In this study, the effects of external electric fields on absorption and fluorescence spectra were investigated to obtain the PTCDI parameters. The PTCDI substituted by an octyl group (N,N'-Dioctyl-3,4,9,10-perylenedicarboximide) dispersed in a polymethyl methacrylate (PMMA) matrix was studied in this work. The features of vibronic progression in the absorption spectrum were analogous to those observed in solution. The red shift of the absorption band caused by the Stark effect was mainly observed in the presence of an external electric field. Changes in parameters such as the dipole moment and polarizability between the ground and the Franck-Condon excited states of the PTCDI monomer were determined. The fluorescence spectrum shows a contribution from a broad fluorescence band at wavelengths longer than the monomer fluorescence band. This broad fluorescence is ascribed to the excimer-like fluorescence of PTCDI. The effects of the electric field on the fluorescence spectrum, known as the Stark fluorescence or electrofluorescence spectrum, were measured. Fluorescence quenching is observed in the presence of an external electric field. The change in the polarizability of the monomer fluorescence band is in good agreement with that of the electroabsorption spectrum. A larger change in the polarizability was observed for the excimer-like fluorescence band than that for the monomer band. This result is consistent with exciton delocalization between PTCDI molecules in the excimer-like state.
Collapse
Affiliation(s)
| | | | - Toshifumi Iimori
- Department of Sciences and Informatics, Muroran Institute of Technology, Mizumoto-cho 27-1, Muroran 050-8585, Hokkaido, Japan; (M.B.R.); (A.I.)
| |
Collapse
|
2
|
Clark JA, Robinson S, Espinoza EM, Bao D, Derr JB, Croft L, O'Mari O, Grover WH, Vullev VI. Poly(dimethylsiloxane) as a room-temperature solid solvent for photophysics and photochemistry. Phys Chem Chem Phys 2024; 26:8062-8076. [PMID: 38372740 DOI: 10.1039/d3cp05413f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Medium viscosity strongly affects the dynamics of solvated species and can drastically alter the deactivation pathways of their excited states. This study demonstrates the utility of poly(dimethylsiloxane) (PDMS) as a room-temperature solid-state medium for optical spectroscopy. As a thermoset elastic polymer, PDMS is transparent in the near ultraviolet, visible, and near infrared spectral regions. It is easy to mould into any shape, forming surfaces with a pronounced smoothness. While PDMS is broadly used for the fabrication of microfluidic devices, it swells in organic solvents, presenting severe limitations for the utility of such devices for applications employing non-aqueous fluids. Nevertheless, this swelling is reversible, which proves immensely beneficial for loading samples into the PDMS solid matrix. Transferring molecular-rotor dyes (used for staining prokaryotic cells and amyloid proteins) from non-viscous solvents into PDMS induces orders-of-magnitude enhancement of their fluorescence quantum yield and excited-state lifetimes, providing mechanistic insights about their deactivation pathways. These findings demonstrate the unexplored potential of PDMS as a solid solvent for optical applications.
Collapse
Affiliation(s)
- John A Clark
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
| | - Samantha Robinson
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
| | - Eli M Espinoza
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Duoduo Bao
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
| | - James B Derr
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
| | - Luca Croft
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
| | - Omar O'Mari
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
| | - William H Grover
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
| | - Valentine I Vullev
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
- Department of Chemistry, University of California, Riverside, CA 92521, USA
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
- Materials Science and Engineering Program, University of California, Riverside, CA 92521, USA
| |
Collapse
|
3
|
Huff JS, Duncan KM, van Galen CJ, Barclay MS, Knowlton WB, Yurke B, Davis PH, Turner DB, Stanley RJ, Pensack RD. High-sensitivity electronic Stark spectrometer featuring a laser-driven light source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:094103. [PMID: 37728421 DOI: 10.1063/5.0153428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 08/21/2023] [Indexed: 09/21/2023]
Abstract
We report developmental details of a high-sensitivity Stark absorption spectrometer featuring a laser-driven light source. The light source exhibits intensity fluctuations of ∼0.3% over timescales ranging from 1 min to 12 h, minimal drift (≤0.1%/h), and very little 1/f noise at frequencies greater than 200 Hz, which are comparable to or better than an arc-driven light source. Additional features of the spectrometer include balanced detection with multiplex sampling, which yielded lower noise in A, and constant wavelength or wavenumber (energy) spectral bandpass modes. We achieve noise amplitudes of ∼7 × 10-4 and ∼6 × 10-6 in measurements of single A and ΔA spectra (with 92 data points) taking ∼7 and ∼19 min, respectively.
Collapse
Affiliation(s)
- J S Huff
- Micron School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
| | - K M Duncan
- Micron School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
| | - C J van Galen
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - M S Barclay
- Micron School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
| | - W B Knowlton
- Micron School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
- Department of Electrical and Computer Engineering, Boise State University, Boise, Idaho 83725, USA
| | - B Yurke
- Micron School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
- Department of Electrical and Computer Engineering, Boise State University, Boise, Idaho 83725, USA
| | - P H Davis
- Micron School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
- Center for Advanced Energy Studies, Idaho Falls, Idaho 83401, USA
| | - D B Turner
- Micron School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
| | - R J Stanley
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - R D Pensack
- Micron School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
| |
Collapse
|
4
|
Islam A, Syundo K, Iimori T. Charge-transfer state and state mixing in tetracyanoquinodimethane probed using electroabsorption spectroscopy. Phys Chem Chem Phys 2023; 25:21317-21323. [PMID: 37490308 DOI: 10.1039/d3cp01669b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Tetracyanoquinodimethane (TCNQ) is an important constituent of organic conductors and a versatile electron acceptor. TCNQ exhibited thermally activated delayed fluorescence and an unusually long fluorescence lifetime. In this study, we studied the Stark effect on the absorption spectrum of TCNQ using electroabsorption spectroscopy to gain insights into its photophysics. The electroabsorption spectrum was simulated using multiple absorption bands for different electronic states, which were characterized by different dipole moments and polarizabilities. These electronic states are identified as a locally excited (LE) state with a high oscillator strength and zero dipole moment, and an intramolecular charge transfer (ICT) state with a nonzero dipole moment. The mixing of the LE state with the ICT state is augmented when the molecule is perturbed by an electric field. We provide tangible experimental evidence establishing the key role of mixing between the emissive LE and nonemissive ICT states in the deactivation pathway of electronically excited TCNQ. The dipole moment of the ICT state suggests symmetry breaking of the structure belonging to the D2h point group.
Collapse
Affiliation(s)
- Ahatashamul Islam
- Department of Sciences and Informatics, Muroran Institute of Technology, Mizumoto-cho 27-1, Muroran, Hokkaido 050-8585, Japan.
| | - Kensuke Syundo
- Department of Sciences and Informatics, Muroran Institute of Technology, Mizumoto-cho 27-1, Muroran, Hokkaido 050-8585, Japan.
| | - Toshifumi Iimori
- Department of Sciences and Informatics, Muroran Institute of Technology, Mizumoto-cho 27-1, Muroran, Hokkaido 050-8585, Japan.
| |
Collapse
|