Pd_xAu_1-x alloys for opto-electronic devices from surface plasmon resonance sensors to photocatalysts

Pd_xAu_1-x alloys have shown promise as good candidates for applications in surface plasmon resonance (SPR) based sensors with tunable frequency and catalysis. In this work, we perform calculations using the transfer matrix method, Mie scattering, and finite-difference-time-domain analysis to evaluate the merit of various concentrations of Pd_xAu_1-x alloys. We evaluate these alloys as SPR sensors and in photocatalysis systems in seven different media (air, water, ethanol, polyethylene, phenol, and covalent triazine). We show that Au_0.65Pd_0.35 exhibits particular promise for angular-based SPR sensors in covalent triazine, and Au_0.86Pd_0.14 exhibited the best overall merit for angular based SPR sensors with its high sensitivity and good peak definition for all sensing media. Taken together, all alloys exhibit a strong response and show promise as nanoparticle photocatalysts due to their potential for wavelength tunability. Notably, Au_0.86Pd_0.14 demonstrated a particularly strong integrated absorption efficiency in all environments. In an antenna-reactor heterodimer system, all alloys outperformed pure gold in integrated absorption (while maintaining comparable values to pure Pd), with Au_0.86Pd_0.14 outperforming all other alloyed and pure samples.