Abstract: The present invention relates to a photosensitive ring oscillator, its preparation method, and a flexible artificial retina. Specifically, the photosensitive ring oscillators (PROs) based on 2D semiconducting materials have been fabricated on flexible biological compatible substrates, which transduces light information into electrical pulse signals directly, propagating through the optic nerve. The output oscillating frequency varies quasi-linearly with the change of light intensity. The flexible electronic devices can be used as implantable biomimetic retina for artificial vision to recover the sight sense for sight-handicapped people.