NOVELTY - A cascaded photovoltaic/thermophotovoltaic energy conversion apparatus comprises a photovoltaic (PV) device (21) with an upper surface that receives solar radiation and a lower surface that produces a first thermal radiation output; and a first thermophotovoltaic (TPV) device (22) disposed a first predetermined distance below the lower surface of the PV device. The PV device produces a first electric current output. The first TPV device receives the first thermal radiation output and converts the received first thermal radiation output into a second electric current output.    USE - A cascaded photovoltaic/thermophotovoltaic energy conversion apparatus used as power sources for micro-electromechanical systems (MEMS) devices, energy sources in transportation, stand-alone gas furnaces, power systems for navigation of sailing boats, silent power supplies on recreational vehicles, co-generation of electricity and heat, remote electricity generators, transportation co-generation, electric-grid independent appliances, aerospace and military power supplies.    ADVANTAGE - The cascaded photovoltaic/thermophotovoltaic energy conversion apparatus has increased efficiency over conventional photovoltaic and thermophotovoltaic devices, and can significantly improve efficiencies of solar energy conversion.    DETAILED DESCRIPTION - A second thermophotovoltaic device is disposed in a cascaded arrangement a second predetermined distance below the first thermophotovoltaic device. It receives a second thermal radiation output from the first thermophotovoltaic device, and converts the second thermal radiation output into a third electric current output. An INDEPENDENT CLAIM is included for a method of forming the cascaded photovoltaic/thermophotovoltaic energy conversion apparatus.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic view of the cascaded photovoltaic/thermophotovoltaic energy conversion apparatus.    PV device (21)    First TPV device (22)    Output terminals (23, 24)