NOVELTY - Photovoltaic or semiconductor encapsulant comprises polymeric material (P1); and a filler material, where the encapsulant has a thermal conductivity of at least 0.26 watt per meter per Kelvin and a dielectric constant of at least 2 measured at 60 hertz.    USE - As a photovoltaic or semiconductor encapsulant useful in solar panel (claimed).    ADVANTAGE - The solar panel containing photovoltaic cell operates at least 2 degrees C cooler in direct overhead sunlight, and produces at least 0.5 percent more power in direct overhead sunlight compared to a conventional photovoltaic cell or panel and operating in similar conditions. The encapsulant has thermal conductivity of at least 0.26 watt per meter per Kelvin.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for following:    (1) photovoltaic or semiconductor backsheet comprising a polymeric material (P2); and a filler material, where the backsheet has a dielectric constant of at least 2 measured at 60 hertz and a higher thermal conductivity than the polymeric material in neat form;    (2) solar panel comprising a front layer and at least one photovoltaic cell comprising the front layer disposed with respect to a front side of the at least one photovoltaic cell; an encapsulant contacting at least a portion of a back side of the at least one photovoltaic cell and disposed at least partially between the at least one photovoltaic cell and a backsheet, the encapsulant containing a first polymeric material and a first thermal conducting filler material, the encapsulant having a thermal conductivity of at least 0.26 watt per meter per Kelvin and a dielectric constant of at least 2 measured at 60 hertz; and the backsheet; and    (3) making a solar panel involving providing a front layer; placing a first sheet of encapsulant material over at least a portion of the front layer; placing at least one photovoltaic cell over the first sheet of encapsulant material; placing a second sheet of encapsulant material over the at least one photovoltaic cell, where the second sheet of encapsulant material comprising a first polymeric material and a first filler material, the second sheet of encapsulant material having a thermal conductivity of at least 0.26 watt per meter per Kelvin and a dielectric constant of at least 2 measured at 60 hertz; placing a backsheet over the second sheet of encapsulant material, where the backsheet comprising a second polymeric material and a second filler material, the backsheet having a dielectric constant of at least 2 and a higher thermal conductivity than the second polymeric material in neat form; and laminating the solar panel for a sufficient time and a sufficient temperature for sufficient crosslinking of the first sheet or the second sheet.