NOVELTY - An electricity generation device comprises at least one photovoltaic cell that generates electricity from sunlight having first efficiency at first temperature and second efficiency at second temperature, where second efficiency is less than first efficiency; and phase change material (306) in thermal contact with photovoltaic cell having phase change temperature based on first temperature. The phase change temperature is - 40-150 degrees C.    USE - Electricity generation device for solar energy generation system (claimed).    ADVANTAGE - The device reduces amount of incident, thus increasing average operating efficiency; and reduces total range of temperature change, thus maximizing efficiency.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a solar energy generation system comprising solar energy collectors each has first energy generation efficiency at first temperature and second energy generation efficiency at second temperature; and phase change material cells in thermal contact with one or more of solar energy collectors, where energy collection surface is incorporated into exterior surface of a structure including vehicle, roofing shingle (300), plank or flexible sheet;    (2) a method for creating photovoltaic assembly comprising selecting photovoltaic cell having, selecting phase change material, and creating photovoltaic assembly having photovoltaic cell in thermal contact with phase change materials; and    (3) an article of manufacture comprising body enclosing at least one volume; at least one photovoltaic cell on body each has energy collection surface that when exposed to sunlight generates electricity at efficiency determined, at least in part, on temperature of photovoltaic cell.    DESCRIPTION OF DRAWING(S) - The drawing is cross-sectional view illustrating a roofing shingle.    Roofing shingle (300)    Shingle body (304)    Phase change material body (306)    Cavity (312)    Phase change material-filled pockets (316)