a nanodiamond coating for use on a solar cell , the coating including a nanodiamond material suspended in a liquid , wherein the nanodiamond material has a size range from about 1 nm to about 10 nm . methods for improving the efficiency of a solar cell , including mixing a nanodiamond material with a liquid polymer or non - polymer solvent to form a nanodiamond - polymer suspension , forming a coating of the suspension on a top surface of a solar cell , and drying the coating such that a dried nanodiamond - polymer layer remains bonded to the solar cell .