NOVELTY - A thermoplastic resin formulation for use as a light transmitting layer in a photovoltaic module comprises: (a) a light transmitting thermoplastic resin; (b) at least one down conversion material that exhibits a maximum in incident radiation absorption in the range of 280 to 500 nm and a maximum in radiation emission at a relatively longer wavelength in the range of 400 to 900 nm; and (c) a light stabilizer additive that transmits at least about 40 percent of the ultraviolet (UV) electromagnetic radiation having a wavelength in the range of from about 280 nm to about 380 nm.    USE - The thermoplastic resin formulation is useful as light transmitting layer in photovoltaic module (claimed).    ADVANTAGE - The resins provide improved combinations of photovoltaic module durability, energy conversion and cost effectiveness.    DETAILED DESCRIPTION - A thermoplastic resin formulation for use as a light transmitting layer in a photovoltaic module comprises: (a) a light transmitting thermoplastic resin; (b) at least one down conversion material that exhibits a maximum in incident radiation absorption in the range of 280 to 500 nm and a maximum in radiation emission at a relatively longer wavelength in the range of 400 to 900 nm and improves the efficiency of photovoltaic electric current generation in a photovoltaic module; and (c) a light stabilizer additive that transmits at least about 40 percent of the ultraviolet (UV) electromagnetic radiation having a wavelength in the range of from about 280 nm to about 380 nm. INDEPENDENT CLAIMS are:    (1) a sheet material for use as a light transmitting layer in a photovoltaic cell comprising the thermoplastic resin formulation; and    (2) a photovoltaic module for the conversion of incident electromagnetic radiation into electric energy, comprising: (i) a light transmitting exterior surface cover sheet; (ii) at least one light transmitting encapsulation sheet material providing protection to a photovoltaic cell from environmental effects, (iii) a protective exterior surface back sheet and (iv) least one photovoltaic cell adapted to convert into electric energy electromagnetic radiation that has passed through the cover sheet and encapsulation film.