Electronic and Structural Effects in Porphyrin Metal-Organic Framework Sensitizers for Solid-State Dye-Sensitized
Tommy Taing1, Jesus Corona1, Sailaja Muduganti2
1Department of Chemistry and Biochemistry, California State University, Los Angeles, California, USA.
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Porphyrin metal-organic frameworks (PMOFs) offer structurally ordered and compositionally tunable platforms for sensitized photovoltaics. Titanium- and indium-based PMOFs, together with a tin-doped indium analog, were investigated as photosensitizers in solid-state dye-sensitized solar cells (ssDSSCs). Electrochemical and optical measurements confirmed favorable energy-level alignment with the TiO2 conduction band and the hole-transporting material, supporting charge injection and transport. Distinct crystallite morphologies between Ti- and In-based PMOFs govern interfacial geometry and recombination pathways within the mesoporous TiO2 scaffold. In contrast, the enhanced performance of In-PMOF(Sn) relative to In-PMOF is attributed primarily to dopant-induced modifications in redox behavior and interfacial charge-transfer kinetics rather than substantial shifts in frontier orbital energies. Although overall efficiencies remain modest, these findings establish clear structure-kinetics-performance relationships and demonstrate that node chemistry and dopant incorporation provide complementary strategies for tuning interfacial charge-transfer dynamics in PMOF-sensitized ssDSSCs.
