A medical device comprising a least one photocatalytic layer or superhydrophilic layer. In some embodiments, the medical device comprises a waveguide. In some embodiments, the medical device comprises an electrode comprising an optically transparent conductive oxide. In some embodiments, the medical device comprises a electroluminescent layer. In some embodiments, the medical device comprises a photovoltaic cell. According to some embodiments, the medical device comprises a doped semiconductor oxide. A method for increasing the energy efficiency of a photocatalytic surface comprises electrically biasing a transparent conductive oxide layer. A method for illuminating a complex three-dimensional surface comprises illuminating a photocatalytic layer with electromagnetic radiation from an electroluminescent layer. A method for removing or preventing the formation of organic matter on a sensor window.