Enhanced Power Conversion Efficiency in Solution-Processed Rigid CuIn(S,Se)₂ and Flexible Cu(In,Ga)Se₂ Solar Cells Utilizing Plasmonic Au-SiO₂ Core-Shell Nanoparticles

Plasmonic resonance effect triggered by gold nanoparticles (NPs) is utilized to enhance light harvesting in different types of thin-film solar cells. However, there is no report using the plasmonic resonance effect triggered by metal NPs in chalcopyrite absorber-based devices because of the high reactivity between the metal NPs and indium/copper/gallium during the required high-temperature selenization process. In this work, Au NPs encapsulated by a thin protective silicon oxide shell in the chalcopyrite absorber-based solar cells deposited by scalable solution deposition techniques under the 600 °C selenization process are demonstrated. The increased scattering and surface plasmonic resonance induced field generated by the nanoparticles can lead to significant enhancement in light absorption and charge carrier generation across a broad spectral range. Enhanced power conversion efficiency in solution-processed rigid CuIn(S,Se)₂ from 1.95 to 2.26% and flexible Cu(In,Ga)Se₂ solar cells from 9.28% to 10.88% is achieved after the addition of plasmonic Au-SiO₂ core-shell NPs in the absorber layer. This work demonstrates a facile method for chalcopyrite solar cell enhancement, which is compatible with low-cost and high-throughput manufacturing process.