Layer-by-layer assembled porous CdSe films incorporated with plasmonic gold and improved photoelectrochemical behaviors

•A 3D porous CdSe film with plasmonic gold was fabricated by electrodeposition.•A prominent light absorption enhancement of CdSe films was attained by gold plasmon.•The photoelectrochemical response of CdSe was tunable by Au–CdSe bilayer number.•The porous Au–CdSe films had a potential application in energy conversion devices.

A simple method for creating three-dimensional porous wurtzite CdSe films incorporated with plasmonic gold by the electrochemical layer-by-layer assembly was proposed. A prominent enhancement in light absorption of CdSe films was attained by the efficient light scattering of gold plasmons as sub-wavelength antennas and concentrators and the near-field coupling of gold plasmons with the neighboring porous CdSe films. The broadband photocurrent enhancement of Au–CdSe composite systems in the visible light range and the local current maximum between 600 and 700 nm suggested the cooperative action of antenna effects and electromagnetic field enhancement resulting from localized surface plasmon excitation of gold. Furthermore, the photoelectrochemical response of porous Au–CdSe composite films was highly tunable with respect to the number of Au–CdSe bilayer. The optimal short-circuit current and open-circuit potential were obtained in a four-layer Au–CdSe system because the thicker absorber layer with less porous structure might limit the electrolyte diffusion into the hybrid electrode and impose a barrier for electron tunneling and transferring. The highly versatile and tunable properties of assembled porous Au–CdSe composite films demonstrated their potential application in energy conversion devices.

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