Optimization and comparative analysis of Cs ion intercalated H3PMO12O40 photocathode: one-step hydrothermal strategy

The current study focused on fabrication of phosphomolybdic acid (H3PMo12O40) (PMA) and cesium intercalated phosphomolybdic acid (Cs3PMo12O40) (Cs-PMA) thin films via simplistic and low-cost hydrothermal reaction. We explored comparative analysis of PMA and Cs+ intercalated PMA for their optoelectronic and photoelectrochemical properties. UV-Visible absorption study demonstrates the decrement in band gap energy from 2.37 to 2.22 eV, forming a well-grown cubic crystal structure with alteration in the surface morphology. XPS analysis validates the presence of Cs, P, Mo, and O in its valence states of +1, +5, +6, and - 2, respectively. The p-type semiconducting nature of Cs3PMo12O40 films was confirmed by thermoelectric measurement. The photoelectrochemical solar cell exhibited a conversion efficiency (eta) of 0.21 and 0.82% for PMA and Cs-PMA photocathode, respectively. The photoelectrochemical performance of PMA and Cs-PMA photocathodes was thoroughly described using Nyquist plots and a circuit model of the electron impedance spectra. The enhancement in the conversion efficiency is attributed to compact nanospheres like microstructures with improved crystallinity as well as optimal band gap energy of Cs-PMA photocathode.

Automated summary

The study focused on fabricating PMA and Cs-PMA thin films via low-cost hydrothermal reaction and compared their optoelectronic and photoelectrochemical properties, with Cs-PMA showing higher efficiency. XPS analysis confirmed the p-type semiconducting nature of Cs3PMo12O40 films, and the enhanced conversion efficiency of Cs-PMA was attributed to its optimal band gap energy and improved crystallinity.