Metal-blacks for plasmonic enhancement of solar-cell efficiency

This Phase I STTR proposal will demonstrate nanostructured “metal-black” coatings to enhance absorption by thin film solar cells. The problem is that silicon has low absorption due to its indirect gap. The opportunity is that nano-scale metallic scattering centers increase the effective optical path length and enhance the solar electric-field strength in thin-film solar cells, leading to more efficient harvesting of solar photons. We propose deposition of so-called “metal blacks”, a nano-structured conductor that requires no lithographic patterning and gives a broad particle-size distribution. Effects of coverage, particle size distribution, co-deposition of dielectric polymers, and co-deposition of different metal-blacks will be investigated. The role of plasma oscillations will be elucidated and optimized by correlating efficiency improvements with Photo-Electron Emission Microscopy images of resonance hot-spot distributions. BENEFIT: Anticipated benefits of this research are order-of-magnitude increases in light harvesting and photo-voltaic conversion efficiency by means of a simple low-cost coating process. This can substantially decrease the number and weight of solar panels. In addition to usual photo-voltaic power generation, commercial opportunities significantly include space-flight and airborne applications having restricted weight budgets.