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Pompetti N, Smyser KE, Feingold B, Owens R, Lama B, Sharma S, Damrauer NH, Johnson JC. Tetracene Diacid Aggregates for Directing Energy Flow toward Triplet Pairs. J Am Chem Soc 2024; 146. [PMID: 38606884 PMCID: PMC11046478 DOI: 10.1021/jacs.4c02058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/13/2024]
Abstract
A comprehensive investigation of the solution-phase photophysics of tetracene bis-carboxylic acid [5,12-tetracenepropiolic acid (Tc-DA)] and its related methyl ester [5,12-tetracenepropynoate (Tc-DE)], a non-hydrogen-bonding counterpart, reveals the role of the carboxylic acid moiety in driving molecular aggregation and concomitant excited-state behavior. Low-concentration solutions of Tc-DA exhibit similar properties to the popular 5,12-bis((triisopropylsilyl)ethynl)tetracene, but as the concentration increases, evidence for aggregates that form excimers and a new mixed-state species with charge-transfer (CT) and correlated triplet pair (TT) character is revealed by transient absorption and fluorescence experiments. Aggregates of Tc-DA evolve further with concentration toward an additional phase that is dominated by the mixed CT/TT state which is the only state present in Tc-DE aggregates and can be modulated with the solvent polarity. Computational modeling finds that cofacial arrangement of Tc-DA and Tc-DE subunits is the most stable aggregate structure and this agrees with results from 1H NMR spectroscopy. The calculated spectra of these cofacial dimers replicate the observed broadening in ground-state absorption as well as accurately predict the formation of a near-UV transition associated with a CT between molecular subunits that is unique to the specific aggregate structure. Taken together, the results suggest that the hydrogen bonding between Tc-DA molecules and the associated disruption of hydrogen bonding with solvent produce a regime of dimer-like behavior, absent in Tc-DE, that favors excimers rather than CT/TT mixed states. The control of aggregate size and structure using distinct functional groups, solute concentration, and solvent in tetracene promises new avenues for its use in light-harvesting schemes.
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Affiliation(s)
- Nicholas
F. Pompetti
- National
Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, United States
- University
of Colorado, Boulder, Colorado 80401, United States
| | - Kori E. Smyser
- University
of Colorado, Boulder, Colorado 80401, United States
| | | | - Raythe Owens
- University
of Colorado, Boulder, Colorado 80401, United States
| | - Bimala Lama
- University
of Colorado, Boulder, Colorado 80401, United States
| | - Sandeep Sharma
- University
of Colorado, Boulder, Colorado 80401, United States
| | - Niels H. Damrauer
- University
of Colorado, Boulder, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute, University
of Colorado Boulder, Boulder, Colorado 80401, United States
| | - Justin C. Johnson
- National
Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute, University
of Colorado Boulder, Boulder, Colorado 80401, United States
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Dill RD, Smyser KE, Rugg BK, Damrauer NH, Eaves JD. Entangled spin-polarized excitons from singlet fission in a rigid dimer. Nat Commun 2023; 14:1180. [PMID: 36859382 PMCID: PMC9977721 DOI: 10.1038/s41467-023-36529-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 01/31/2023] [Indexed: 03/03/2023] Open
Abstract
Singlet fission, a process that splits a singlet exciton into a biexciton, has promise in quantum information. We report time-resolved electron paramagnetic resonance measurements on a conformationally well-defined acene dimer molecule, TIPS-BP1', designed to exhibit strongly state-selective relaxation to specific magnetic spin sublevels. The resulting optically pumped spin polarization is a nearly pure initial state from the ensemble. The long-lived spin coherences modulate the signal intrinsically, allowing a measurement scheme that substantially removes noise and uncertainty in the magnetic resonance spectra. A nonadiabatic transition theory with a minimal number of spectroscopic parameters allows the quantitative assignment and interpretation of the spectra. In this work, we show that the rigid dimer TIPS-BP1' supports persistent spin coherences at temperatures far higher than those used in conventional superconducting quantum hardware.
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Affiliation(s)
- Ryan D. Dill
- grid.266190.a0000000096214564Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309 USA
| | - Kori E. Smyser
- grid.266190.a0000000096214564Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309 USA
| | - Brandon K. Rugg
- grid.419357.d0000 0001 2199 3636National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Niels H. Damrauer
- grid.266190.a0000000096214564Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309 USA ,grid.266190.a0000000096214564Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO 80309 USA
| | - Joel D. Eaves
- grid.266190.a0000000096214564Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309 USA ,grid.266190.a0000000096214564Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO 80309 USA
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Abstract
Short coherence times present a primary obstacle in quantum computing and sensing applications. In atomic systems, clock transitions (CTs), formed from avoided crossings in an applied Zeeman field, can substantially increase coherence times. We show how CTs can dampen intrinsic and extrinsic sources of quantum noise in molecules. Conical intersections between two periodic potentials form CTs in electron paramagnetic resonance experiments of the spin-polarized singlet fission photoproduct. We report on a pair of CTs for a two-chromophore molecule in terms of the Zeeman field strength, molecular orientation relative to the field, and molecular geometry.
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Affiliation(s)
- Sina G Lewis
- Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Kori E Smyser
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Joel D Eaves
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, USA
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Abstract
Singlet fission is a photoconversion process that generates a doubly excited, maximally spin entangled pair state. This state has applications to quantum information and computing that are only beginning to be realized. In this article, we construct and analyze a spin-exciton hamiltonian to describe the dynamics of the two-triplet state. We find the selection rules that connect the doubly excited, spin-singlet state to the manifold of quintet states and comment on the mechanism and conditions for the transition into formally independent triplets. For adjacent dimers that are oriented and immobilized in an inert host, singlet fission can be strongly state-selective. We make predictions for electron paramagnetic resonance experiments and analyze experimental data from recent literature. Our results give conditions for which magnetic resonance pulses can drive transitions between optically polarized magnetic sublevels of the two-exciton states, making it possible to realize quantum gates at room temperature in these systems.
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Affiliation(s)
- Kori E Smyser
- Department of Chemistry, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Joel D Eaves
- Department of Chemistry, University of Colorado Boulder, Boulder, CO, 80309, USA.
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Hill AH, Smyser KE, Kennedy CL, Massaro ES, Grumstrup EM. Screened Charge Carrier Transport in Methylammonium Lead Iodide Perovskite Thin Films. J Phys Chem Lett 2017; 8:948-953. [PMID: 28181440 DOI: 10.1021/acs.jpclett.7b00046] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
While organometal halide perovskites are promising for a variety of optoelectronic applications, the morphological and compositional defects introduced by solution processing techniques have hindered efforts at understanding their fundamental properties. To provide a detailed picture of the intrinsic carrier transport properties of methylammonium lead iodide without contributions from defects such as grain boundaries, we utilized pump-probe microscopy to measure diffusion in individual crystalline domains of a thin film. Direct imaging of carrier transport in 25 individual domains yields diffusivities between 0.74 and 1.77 cm2 s-1, demonstrating single-crystal-like, long-range transport characteristics in a thin film architecture. We also examine the effects of excitation density on carrier diffusivity, finding that transport is nearly independent of photoexcited carrier density between 6 × 1017 cm-3 and 4 × 1019 cm-3. Transport modeling of the observed density independence suggests that strong carrier-phonon scattering coupled with a large static relative permittivity is responsible for the unusual transport characteristics of methylammonium perovskite.
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Affiliation(s)
- Andrew H Hill
- Montana Materials Science Program and ‡Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Kori E Smyser
- Montana Materials Science Program and ‡Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Casey L Kennedy
- Montana Materials Science Program and ‡Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Eric S Massaro
- Montana Materials Science Program and ‡Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Erik M Grumstrup
- Montana Materials Science Program and ‡Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
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