Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

Ph.D. in Chemistry

First Advisor

Jared H. Delcamp

Second Advisor

Nathan I. Hammer

Third Advisor

Ryan C. Fortenberry


University of Mississippi

Relational Format



An urgent challenge limiting the improvement of dye-sensitized solar cell (DSC) technology is the availability of chromophores capable of harvesting the full spectrum of solar irradiation; this is especially evident at longer wavelengths. Therefore, the achievable power conversion efficiency (PCE) is effectively capped due to limited photocurrent generation. Molecular design strategies involving proaromaticity and cross-conjugation are employed in this work to facilitate access to low-energy near-infrared (NIR) photons. Utilizing the ubiquitous Donor–p-spacer–Acceptor (D–p–A) architecture, these concepts are studied by incorporating an indolizine donor (RR13 and RR14), and thieno[3,4-b]pyrazine (allowing additional substitution for cross-conjugation, JW1) and thieno[3,4-b]thiophene (AP25) p-spacers. The sensitizers are assessed computationally and systematically characterized. Proaromaticity is shown to reduce optical bandgaps relative to reference dyes in all cases, absorbing photons of energy as low as ~1.38 eV when immobilized on TiO2. As a result, optimized photovoltaic devices (via cosensitization and other photon management strategies) give outstanding photocurrent for allorganic DSCs in excess of 20 mA/cm2 and reach a record 25 mA/cm2 in the case of co-sensitized AP25. Subsequent integration within a sequential series multijunction device (SSM–DSC) results in a high 10.1% PCE and demonstrates practicality as a power source for the water-splitting reaction with 3.9% solar-to-hydrogen efficiency in a cost-effective, precious metal-free system. Finally, our champion NIR organic DSC is shown to be a competitive alternative to benchmark Ru DSCs and market-dominating Si and GaAs PVs as a back subcell in multijunction solar cells due to superior performance under filtered or reduced illumination.



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