Light Trapping on Plasmonic-Photonic Nanostructured Fluorine-Doped Tin Oxide

Plasmonic Au nanoparticles of similar to 50-200 nm in diameter were generated via thermally assisted self-assembly from Au films evaporated on fluorine-doped tin oxide (FTO). A comparative study has been made on the light trapping effects of the plasmonic Au nanoparticles on original FTO and FTO with photonic nanopatterns fabricated using nanoimprint lithography. While strong localized surface plasmon resonance (LSPR) in the visible spectrum has been confirmed in both cases, quantitative differences exist and may be attributed to the Au nanoparticle morphology and their interface with FTO. In particular, the LSPR frequency depends on the Au nanoparticle structure and size, while the LSPR peak width is affected by FTO surface morphology (original or nanopatterned). It has been found that the combined plasmonic-photonic nanostructured FTO has the best light trapping, which agrees well with the finite difference time domain simulations and provides a promising transparent electrode for high-efficiency thin film solar cells and other optoelectronic devices.