TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Process: In the process (M1), the nanodiamond material comprises particles having a size of 5-7 nm. The suspension includes the nanodiamond material in an amount of less than or equal to 0.1 wt./wt.%. The nanodiamond-polymer layer has a thickness of less than or equal to 25 microns. The step of forming a coating includes: (i) applying the suspension to the top surface of the solar cell; and drawing a blade across the suspension to form the coating to a desired thickness; (ii) screen printing the suspension on the top of the solar cell; (iii) dipping the solar cell into a bath of the suspension; withdrawing the solar cell from the bath such that a wet layer of the suspension adheres to the top of the surface of the solar cell as the coating; and drying the coating by evaporation of solvent in the suspension. The process further involves: mixing a nanodiamond material with a non-polymer solvent to form a second suspension; coating the second suspension on a top surface of a photovoltaic material within the solar cell to form a coating; drying the coating such that a dried nanodiamond-polymer layer remains bonded to the photovoltaic material. The second suspension includes less than or equal to 0.1 wt./wt.% of the nanodiamond material. The nanodiamond-polymer layer has thickness of less than or equal to 100 microns.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The non-polymer solvent is dimethyl sulfoxide.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The liquid in the coating (C1) comprises a non-polymer or polymer solvent. The liquid polymer is polyvinylidene fluoride. EXAMPLE - Nanodiamond was blended into a liquid PVDF material for coating on a solar cell. In one example, a suspension including: nanodiamond (0.01 wt./wt.%); Kynara (RTM: polyvinylidine fluoride (PVDF) resin) (used as the polymer matrix material) (0.01 wt./wt.%); and dimethyl sulfoxide (DMSO) (balance), was prepared. A coating of the suspension was applied to the top-surface of the solar cell and allowed to dry, leaving the nanodiamond particles suspended in a film of PVDF polymer in a narrow band of distances above the top surface of the solar cell. Coatings having thickness of 40 microns to 100 microns were tested, and the resulting change in efficiency of the solar cell was measured. It was observed that the efficiency improvement in the solar cell was inversely proportional to wet coating thickness, with a 100-micron coating achieving more than a 4% increase in efficiency and a 40-micron coating achieving nearly 7.5% increase in efficiency.