High performance photovoltaic devices are provided. Certain embodiments relate to the use of Boron-Nitride (BN) thin films as anti-reflection coating (ARC) material on Si and GaAs solar cells. A low and wide reflectance window covering a large energy range of the solar spectrum is available. For a large part of the useful solar spectrum, the index of refraction of the grown BN thin films remains constant at about 2.8. In another embodiment, a BN ARC is applied directly on ordinary window glass providing the device's mechanical strength.