Improved photosensing devices and methods are disclosed. Such devices and methods have application, among other things, as retinal implants and in imaging devices. In one embodiment, an exemplary retinal implant can include an array of photoreceptors adapted for positioning in the eye. Each photoreceptor can include a core, for example a carbon nanostructure, and a shell. The shell can include a light- responsive layer, and in many cases, the light-responsive layer can be formed of two semiconductor layers forming a heterojunction. The photoreceptors can be adapted to generate an electric field in response to incident light so as to stimulate a retinal neuron in its vicinity. The photoreceptors can be micron-sized or nano-sized, and can be arranged in densities similar to the density of rods and cones in the human eye. In one embodiment, an exemplary sensor for an imaging device can include a plurality of photosensors disposed on a substrate. Each photosensor can include a carbon nanostructure, a light-responsive layer coating at least a portion of the carbon nanostructure. The nanostructure and the light-responsive layer can be coupled to a set of contacts such that an electrical signal (e.g., voltage or current) developed across the contacts can represent the detection of light incident thereon and can correspond to a pixel in an image.
ARTIFICIAL RETINAL IMPLANT