Graduate Thesis Or Dissertation


Optical and Spin Properties of Singlet Fission Dimers Public Deposited

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  • Singlet fission is a process by which two triplet excitons (T1) are generated from a single photon via the electronic coupling between adjacent chromophores. This process has been extensively studied for its exciton-multiplication ability, which makes it a promising area of research for solar cell applications.

    Coupled triplet pairs (1TT, 3TT, and 5TT) formed in singlet fission are crucial for T1 generation. However, the evolution between the three different spin states and further to T1 is not fully understood. To gain a deeper understanding of the process, a weakly coupled organic dimer, Et2Si(TIPSTT)2 , was selected for investigation with transient absorption spectroscopy (fs/nsTA) and electron paramagnetic resonance spectroscopy (EPR). A straightforward mechanism is presented and supported in this thesis.

    In addition to the solar cell applications, singlet-fission-born 5TT has been reported as a promising candidate for qubits or qudits in quantum information science. Instead of maximizing T1 yield for solar cell applications, we optimize the strength of electronic coupling between the chromophores to maximize the 5TT yield while preventing the dissociation from 5TT to T1. Based on an analysis using a model spin exciton Hamiltonian, we studied a parallel-tetracene dimer bridged with pyrene to make a highly spin-polarized 5TT-based qubit. High 5TT yield is observed and the qubit characterization is also reported in this thesis.

    Overall, the investigation of singlet fission and its applications in solar cells and quantum information science hold great promise for advancing our understanding of fundamental physics and developing practical technologies.

Date Issued
  • 2023-06-11
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Last Modified
  • 2024-01-18
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