NOVELTY - A solar cell (600), comprises: a first metal layer (606) disposed on a substrate (607); a material layer (605) formed above the first metal layer, and operable as an electron reflector layer; an absorber material layer (604) formed above the material layer; a buffer material layer (603) formed above to the absorber material layer; a transparent conductive oxide material layer (602) formed above the buffer material layer; and a second metal layer (601) formed above the transparent conductive oxide material layer.    USE - As a solar cell (Claimed).    ADVANTAGE - The present solar cell has improved efficiency by including reflector layers between absorber materials and back contact metal layer; and also enhances back optical reflectance and quantum efficiency as possible back contact metal materials at the absorber backend.    DETAILED DESCRIPTION - A solar cell (600), comprises: a first metal layer (606) disposed on a substrate (607); a material layer (605) formed above the first metal layer, and operable as an electron reflector layer; an absorber material layer (604) formed above the material layer; a buffer material layer (603) formed above to the absorber material layer; a transparent conductive oxide material layer (602) formed above the buffer material layer; and a second metal layer (601) formed above the transparent conductive oxide material layer. The material layer is p+-type. The buffer material layer is n+-type. The material layer has a wider band gap than the absorber material layer; has an energy band gap of 0.3-0.7 electron volts higher than the energy band gap of the absorber material layer; and has an energy band gap height of 1.4 electron volts. An ohmic contact is present at an interface between the material layer and the first metal layer. The solar cell further comprises an antireflection coating layer between the second metal layer and the transparent conductive oxide material layer. An INDEPENDENT CLAIM is included for creating a thin film photovoltaic solar cell, involving: forming first metal layer above the substrate; forming material layer above the first metal layer; forming absorber material layer above the material layer; forming transparent conductive oxide materials above the buffer material layer; and forming a second metal layer above the transparent conductive oxide material layer, where the material is formed by a selenization process involving exposing the absorber material layer to at least one of H2Se, Se vapor, or diethylselenide.    DESCRIPTION OF DRAWING(S) - The figure shows a simplified schematic view of a solar cell having an electron reflector material layer formed on absorber material layer and back contact metal layer.    Solar cell (600)    Front contact grid material layer (601)    Transparent conductive oxide material layer (602)    Buffer material layer (603)    Copper indium gallium selenide absorber material layer (604)    Electron reflector material layer (605)    Back contact metal layer (606)    Substrate (607)    Anti-reflection coating layer (610)