Light-assisted patterning of salt precipitation on photovoltaic LiNbO3 substrates

Abstract

AbstractThe control of salt crystallization on a surface has important implications in many technological and industrial applications. In this work, we propose and demonstrate an optoelectrical method to define and control the spatial distribution of salt crystallization on a lithium niobate photovoltaic substrate. It is based on the bulk photovoltaic effect that generates an electric field on the illuminated regions of the crystal. The salt only crystallizes on these illuminated regions of the substrate. Single salt spots or more complicated spatial patterns, defined by the light intensity spatial distribution, have been achieved. In particular, some results have been obtained using scanning/moving laser beams, i.e., “drawing” the saline patterns. The role of light exposure time and salt concentration in the aqueous solution has been studied. The method has been checked with several salts with successful results showing its general applicability. A discussion on the possible physical mechanisms behind the method and their implication for the operation of photovoltaic platforms in other applications is also included.