Presentation Title

Synthesis of Tetracene Derivatives Useful for Singlet Fission

Faculty Mentor

Ming Lee Tang

Start Date

23-11-2019 10:00 AM

End Date

23-11-2019 10:45 AM

Location

235

Session

poster 3

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Solar cell efficiency could potentially be increased by exceeding the Shockley-Queisser limit through singlet fission. The Shockley-Queisser limit is the theoretical maximum efficiency of p-n junctions in a solar cell. Due to this limit, less than half of the light energy incident on a conventional photovoltaic material is converted to electrical energy. Some of this lost energy could be harvested through singlet fission. In the organic molecule, tetracene, singlet fission occurs efficiently like so: an absorbed photon creates a singlet state that splits into two triplet states—one in the original chromophore and one in a neighboring chromophore. Inorganic colloidal PbS nanocrystals (NC) then harvest the energy from triplet excitons generated by the tetracene. This energy transfer is known as the Dexter process, which is a simultaneous, correlated transfer of charge or energy from a donor to an acceptor non-radiatively. In this work, tetracene acts as the donor while PbS is the acceptor. Dexter transfer is enhanced by covalently attaching both species together to promote wavefunction overlap between donor and acceptor. However, non-functionalized tetracene cannot be attached to the nanocrystal. Therefore, tetracene must be functionalized in order to bind the species together. The target of our synthesis is tetracene functionalized with carboxylic acid and nonylphenyl groups. The former allows for PbS-Tetracene bonds while the latter serves to solvate the otherwise insoluble tetracene. This work describes the organic synthesis of our target and characterizes its synthesis intermediates by NMR and UV-vis spectroscopy.

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Nov 23rd, 10:00 AM Nov 23rd, 10:45 AM

Synthesis of Tetracene Derivatives Useful for Singlet Fission

235

Solar cell efficiency could potentially be increased by exceeding the Shockley-Queisser limit through singlet fission. The Shockley-Queisser limit is the theoretical maximum efficiency of p-n junctions in a solar cell. Due to this limit, less than half of the light energy incident on a conventional photovoltaic material is converted to electrical energy. Some of this lost energy could be harvested through singlet fission. In the organic molecule, tetracene, singlet fission occurs efficiently like so: an absorbed photon creates a singlet state that splits into two triplet states—one in the original chromophore and one in a neighboring chromophore. Inorganic colloidal PbS nanocrystals (NC) then harvest the energy from triplet excitons generated by the tetracene. This energy transfer is known as the Dexter process, which is a simultaneous, correlated transfer of charge or energy from a donor to an acceptor non-radiatively. In this work, tetracene acts as the donor while PbS is the acceptor. Dexter transfer is enhanced by covalently attaching both species together to promote wavefunction overlap between donor and acceptor. However, non-functionalized tetracene cannot be attached to the nanocrystal. Therefore, tetracene must be functionalized in order to bind the species together. The target of our synthesis is tetracene functionalized with carboxylic acid and nonylphenyl groups. The former allows for PbS-Tetracene bonds while the latter serves to solvate the otherwise insoluble tetracene. This work describes the organic synthesis of our target and characterizes its synthesis intermediates by NMR and UV-vis spectroscopy.