A bioinspired Au-Cu_1.97S/Cu₂S film with efficient low-angle-dependent and thermal-assisted photodetection properties

Inspired by the geological processes, this study develops an innovative low-concentration-ratio H₂ reduction method to reduce the stoichiometric Au-CuS nanoparticles to produce completely reduced stoichiometric Cu₂S with "invisible" Au achieved for solid solution Au enhancement. A stable Au-Cu_1.97S/Cu₂S micro/nano-composite is then formed by spontaneous oxidation. From this composite, in combination with biomimetic technology, an omnidirectional photoabsorption and thermoregulated film (Au-Cu_1.97S/Cu₂S-C-T_FW) is designed and fabricated as a photothermal-assisted and temperature-autoregulated photodetector for broadband and low-angle-dependent photodetection that presents good performance with high responsivity (26.37 mA/W), detectivity (1.25×10⁸ Jones), and good stability at low bias (0.5 V). Solid solution Au exhibits significantly enhanced photodetection (1,000 times). This study offers a new concept for improving the stability and photoelectric properties of copper chalcogenides. Moreover, it opens up a new avenue toward enhancing the performance of optoelectronic and photovoltaic devices using solid solution metal atoms and thermal-assisted, anti-overheating temperature autoregulation.