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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.
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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
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2
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Rumble CA, Vauthey E. Molecular Dynamics Simulations of Bimolecular Electron Transfer: the Distance-Dependent Electronic Coupling. J Phys Chem B 2021; 125:10527-10537. [PMID: 34519508 DOI: 10.1021/acs.jpcb.1c05013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the distance dependence of the parameters underpinning Marcus theory is imperative when interpreting the results of experiments on electron transfer (ET). Unfortunately, most of these parameters are difficult or impossible to access directly with experiments, necessitating the use of computer simulations to model them. In this work, we use molecular dynamics simulations in conjunction with constrained density functional theory calculations to study the distance dependence of the electronic coupling matrix element, |HRP|, for bimolecular ET. Contrary to what is typically assumed for such intermolecular reactions, we find that the magnitude of |HRP| does not decay exponentially with the center-of-mass separation of the reactants, rCOM. The addition of other simple measures of donor/acceptor (D/A) orientation did not improve the correlation of |HRP| with rCOM. Using the minimum distance separation, rmin, of the reactants as the structural descriptor allowed the system to be partitioned into high-coupling/close-contact and low-coupling/non-contact regimes, but large fluctuations of |HRP| were still found for the close-contact reactant pairs. Despite the persistent large fluctuations of |HRP|, its mean value was found to decay piecewise exponentially with increasing rmin, which was attributed to significant changes in the average D/A pair structure. The results herein advise one to use caution when interpreting the experimental results derived from spherical reactant models of bimolecular ET.
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Affiliation(s)
- Christopher A Rumble
- Départment de Chimie Physique, Université de Genève, 30 Quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
| | - Eric Vauthey
- Départment de Chimie Physique, Université de Genève, 30 Quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
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3
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Holtrop F, Jupp AR, van Leest NP, Paradiz Dominguez M, Williams RM, Brouwer AM, de Bruin B, Ehlers AW, Slootweg JC. Photoinduced and Thermal Single-Electron Transfer to Generate Radicals from Frustrated Lewis Pairs. Chemistry 2020; 26:9005-9011. [PMID: 32259331 PMCID: PMC7496419 DOI: 10.1002/chem.202001494] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/06/2020] [Indexed: 12/17/2022]
Abstract
Archetypal phosphine/borane frustrated Lewis pairs (FLPs) are famed for their ability to activate small molecules. The mechanism is generally believed to involve two-electron processes. However, the detection of radical intermediates indicates that single-electron transfer (SET) generating frustrated radical pairs could also play an important role. These highly reactive radical species typically have significantly higher energy than the FLP, which prompted this investigation into their formation. Herein, we provide evidence that the classical phosphine/borane combinations PMes3 /B(C6 F5 )3 and PtBu3 /B(C6 F5 )3 both form an electron donor-acceptor (charge-transfer) complex that undergoes visible-light-induced SET to form the corresponding highly reactive radical-ion pairs. Subsequently, we show that by tuning the properties of the Lewis acid/base pair, the energy required for SET can be reduced to become thermally accessible.
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Affiliation(s)
- Flip Holtrop
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Andrew R. Jupp
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Nicolaas P. van Leest
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | | | - René M. Williams
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Albert M. Brouwer
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Bas de Bruin
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Andreas W. Ehlers
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
- Department of ChemistryScience FacultyUniversity of JohannesburgPO Box 254, Auckland ParkJohannesburgSouth Africa
| | - J. Chris Slootweg
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
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4
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Colella M, Danos A, Monkman AP. Less Is More: Dilution Enhances Optical and Electrical Performance of a TADF Exciplex. J Phys Chem Lett 2019; 10:793-798. [PMID: 30726086 PMCID: PMC7005938 DOI: 10.1021/acs.jpclett.8b03646] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 02/06/2019] [Indexed: 05/25/2023]
Abstract
A surprising yet highly practical approach to improve the performance of a TADF exciplex blend is reported. Using the TSBPA donor and PO-T2T acceptor to form an exciplex, we are able to blue shift the emission, increase PLQY from 58 to 80%, and increase the device EQE from 14.8 to 19.2% by simply diluting the exciplex with an inert high triplet energy host material-here either UGH-3 or DPEPO. These effects are explained in terms of an increasing donor-acceptor distance and associated charge separation, while different behaviors observed in the different hosts are attributed to different energy barriers to electron transfer through the host. We expect that the observed performance-enhancing effects of dilution will be general to different exciplex blends and host materials and offer a new way to optimize the electrical properties of exciplex emission layers with narrow blue emission.
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Tierce NT, Chen CH, Chiu TL, Lin CF, Bardeen CJ, Lee JH. Exciton dynamics in heterojunction thin-film devices based on exciplex-sensitized triplet–triplet annihilation. Phys Chem Chem Phys 2018; 20:27449-27455. [DOI: 10.1039/c8cp05261a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A triplet-diffusion-singlet-blocking layer and fluorescent dopant enhance blue emission due to triplet–triplet annihilation in an organic light emitting diode structure.
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Affiliation(s)
- Nathan T. Tierce
- Department of Chemistry, University of California, Riverside
- Riverside
- USA
| | - Chia-Hsun Chen
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering
- National Taiwan University
- Taiwan
- Republic of China
| | - Tien-Lung Chiu
- Department of Electrical Engineering
- Yuan Ze University
- Taiwan
- Republic of China
| | - Chi-Feng Lin
- Department of Electro-Optical Engineering
- National United University
- Taiwan
- Republic of China
| | | | - Jiun-Haw Lee
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering
- National Taiwan University
- Taiwan
- Republic of China
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Ito A, Fang Z, Brennaman MK, Meyer TJ. Long-range photoinduced electron transfer dynamics in rigid media. Phys Chem Chem Phys 2014; 16:4880-91. [PMID: 24473124 DOI: 10.1039/c3cp54801e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In semi-rigid PEG-DMA550 films with added reductive quenchers, electron transfer quenching of the metal-to-ligand charge transfer excited state(s) of [Ru(bpy)3](2+) (bpy = 2,2'-bipyridine) occurs by both rapid, fixed-site, and slow, diffusional, quenching processes. Stern-Volmer analysis of diffusional quenching reveals diffusion-controlled quenching both in the fluid and film with the latter greatly inhibited by the high viscosity of the medium. The data for fixed-site quenching are consistent with electron tunneling with the expected exponential distance dependence. Based on this analysis long-range electron transfer occurs with a distance attenuation factor β of ∼0.47 Å(-1) with a notable decrease, β = 0.16 Å(-1), when the quencher is incorporated into the PEG backbone. Fixed-site electron transfer quenching varies with driving force. Back electron transfer is complex, as expected for a distribution of fixed sites, and varies with power law kinetics.
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Affiliation(s)
- Akitaka Ito
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
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Zarea M, Ratner MA, Wasielewski MR. Electron transfer in a two-level system within a Cole-Davidson vitreous bath. J Chem Phys 2014; 140:024110. [DOI: 10.1063/1.4860972] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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