Date of Award
1-1-2024
Document Type
Dissertation
Degree Name
Ph.D. in Chemistry
First Advisor
Jared H. Delcamp
Second Advisor
Nathan Hammer
Third Advisor
Jonah W. Jurss
School
University of Mississippi
Relational Format
dissertation/thesis
Abstract
Small organic molecules with the ability to access photons at longer wavelengths are greatly needed in the fields of dye sensitized solar cells and biological imaging. Firstly, an urgent challenge limiting the improvement in photocurrent of dye-sensitized solar cell (DSC) technology is the availability of chromophores capable of harvesting the full spectrum of solar irradiation and the judicious employment of these chromophores with other components of the DSC device in order to achieve higher efficiencies. Therefore, strategies are put forward to fabricate and optimize the DSC devices by using novel cross conjugated organic photosensitizers based on benzo[b]thiophene and fused dibenzosilin double donors, which are capable of harvesting photons at longer wavelengths, particularly in the near infrared (NIR) region of the solar spectrum. As a result, optimized photovoltaic devices give outstanding photocurrents and reach a record photocurrent (JSC) value of ~ 27.5 mA/cm2, which is the highest photocurrent in the singly-sensitized DSC field. Secondly, fluorescence imaging with high resolution and sensitivity has been widely studied for bioimaging applications. However, unfavorable light attenuation and autofluorescence in tissues at conventional visible and NIR-I imaging windows (400–1000 nm) have severely restricted imaging depth and resolution. Thus, there is an immediate need in the advancement of fluorophores that can absorb in the NIR-II window (NIR-II, 1000-1700 nm), where low auto-fluorescence, reduced photon scattering, and high tissue penetration depth lead to visualization of deep anatomical features in vivo with high resolution and sensitivity. To achieve this target NIR-II window, xanthene based novel florescent bioimaging dyes were synthesized, which are able to absorb and emit in the NIR-II window. Among xanthene-based emissive dyes, emission values >1200 nm are rare but, in this study, a peak emission value of around ~1310 nm was observed.
Recommended Citation
Kaur, Ravinder, "Small Organic Molecules Absorbing Low Energy Photons for Dye Sensitized Solar Cells and Biological Imaging" (2024). Electronic Theses and Dissertations. 2947.
https://egrove.olemiss.edu/etd/2947