Tunable asymmetric reflectance in silver films near the percolation threshold

TL;DR

This paper demonstrates tunable asymmetric reflectance in nanostructured silver films, linking optical properties to charge percolation, with potential applications in light-harvesting technologies.

Contribution

Introduces a method to produce silver films with adjustable asymmetric reflectance and correlates optical response with charge transport phenomena.

Findings

Reflectance asymmetries are tunable in sign and magnitude.

Spectral crossover point indicates charge percolation onset.

Broadband, dispersion-tunable asymmetric reflectors are achievable.

Abstract

We report on the optical characterization of semicontinuous nanostructured silver films exhibiting tunable optical reflectance asymmetries. The films are obtained using a multi-step process, where a nanocrystalline silver film is first chemically deposited on a glass substrate and then subsequently coated with additional silver via thermal vacuum-deposition. The resulting films exhibit reflectance asymmetries whose dispersions may be tuned both in sign and in magnitude, as well as a universal, tunable spectral crossover point. We obtain a correlation between the optical response and charge transport in these films, with the spectral crossover point indicating the onset of charge percolation. Such broadband, dispersion-tunable asymmetric reflectors may find uses in future light-harvesting systems.