Photovoltaic nanoassembly of nanowire arrays sensitized with colloidal nanocrystals for near-infrared retina photostimulation

Abstract

Nanowires have served as a transformative platform for advanced neural and tissue interfaces. While their photovoltaic properties hold exceptional promise for neural modulation, existing photostimulation approaches predominantly rely on visible light-activated photoelectrochemical mechanisms. Here, we present a solution-processed photovoltaic nanoassembly comprising a ZnO nanowire array sensitized with AgBiS2 nanocrystals that enables efficient near-infrared (NIR) neural stimulation through capacitive photocurrents. By optimizing nanowire morphology and nanocrystal interdigitation, the platform achieves high charge injection densities (tens of microcoulombs per square centimeter) at low NIR intensities (<1 milliwatt per square millimeter). The nanoassembly was subretinally placed in an ex vivo blind rat retina, where it elicited repeatable and robust responses in retinal ganglion cells under NIR pulses. Notably, these responses were achieved at light intensities substantially below established ocular safety limits. The nexus of neuronal systems and nanoassemblies offers potential for enabling unconventional visual prosthetics and advanced neuromodulation therapies.