NOVELTY - The photovoltaic electrochromic device comprises a transparent substrate (702), thin-film solar cells (402) formed on the transparent substrate, an electrochromic thin film disposed on one surface of a cathode and the exposed surface of an anode (404) of the thin-film solar cell, and an electrolyte layer (700) covering the electrochromic thin films. The thin-film solar cells comprise anodes, photoelectric conversion layers, and cathodes (408). A portion of a surface of the anode is exposed from the thin film solar cell, and between the cathodes.    USE - The photovoltaic electrochromic device is useful: as a solar cell for electrical power generation and a smart window for building applications such as utility benefit with grid-tied building integrated photovoltaic (BIPV); and to fabricate color-changing rear view minors, windows for transportation vehicles, car roofs, displays, optical filters and optical sensors.    ADVANTAGE - The photovoltaic electrochromic device provides better efficiency in energy saving, and achieves better color change in electrochromic layers without additional power source.    DETAILED DESCRIPTION - The photovoltaic electrochromic device comprises a transparent substrate (702), thin-film solar cells (402) formed on the transparent substrate, an electrochromic thin film disposed on one surface of a cathode and the exposed surface of an anode (404) of the thin-film solar cell, and an electrolyte layer (700) covering the electrochromic thin films. The thin-film solar cells comprise anodes, photoelectric conversion layers, and cathodes (408). A portion of a surface of the anode is exposed from the thin film solar cell, and between the cathodes. A material of the electrochromic thin film comprises conducting polymer, transition metal oxide, transition metal or Prussian blue. The thin-film solar cell comprises silicon thin-film solar cell, copper indium gallium selenide (CIGS) thin-film solar cell, or cadmium telluride thin film solar cell. The silicon thin-film solar cell comprises amorphous silicon thin-film solar cell, amorphous silicon/multicrystalline silicon tandem thin-film solar cell, amorphous silicon/amorphous silicon tandem thin-film solar cell or multijunction amorphous silicon thin film solar cell. The thin-film solar cells are connected in series, in which anode of one of the thin-film solar cell is electrically connected to the cathode of another thin film solar cell. A shading area of the electrochromic thin film is determined by a width of an interval between the cathodes. A passivation layer is disposed on a sidewall of the photoelectric conversion layer of the thin-film solar cell. The electrolyte layer comprises solid electrolyte or liquid electrolyte. The transparent substrate comprises a glass, plastic or flexible substrate. A transparent non-conductive substrate is arranged for covering the electrolyte layer. A reflective film is disposed on a surface of the transparent non-conductive substrate to form a mirror. A DC/AC inverter is used to convert current generated by the thin-film solar cell into utility grid. A DC charge storage device is arranged to store the current generated by the thin-film solar cell. A thin-film transistor is connected to the anode and the cathode of the thin-film solar cell to control a switch between the thin-film solar cell and an exterior circuit. An INDEPENDENT CLAIM is included for a method of manufacturing a photovoltaic electrochromic device.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of a process for manufacturing a photovoltaic electrochromic device.    Thin film solar cells (402)    Anode (404)    Photoelectric conversion layer (406)    Cathode (408)    Electrolyte layer (700)    Substrate. (702)