NOVELTY - An optoelectronic device comprises functional stack (230) capable of converting light into electricity on substrate (220), and having electrical contact(s) (240) with conductive connection tab coupled to each and defining a border zone (260) on substrate between edges of functional stack and substrate; barrier layer including inorganic films on substrate to cover a portion of functional stack and border zone; and envelope layer including polymer films on substrate to cover a portion of barrier layer, border zone and edges of substrate.    USE - An optoelectronic device (i.e. solar panel) for outdoor installation, particularly including photovoltaic cells for converting sunlight or other light into electricity.    ADVANTAGE - The back and edges of solar panel are protected from a wide variety of mechanical, chemical, electrical, thermal, biological and irradiative damage mechanisms; thus prolonging the useful life of solar panel and lowering total cost of operation. The materials used for protection will not produce by-products that cause internal corrosion or other types of damage, and are impervious to by-products and other damaging effects that may be produced by other parts of the panel. The coatings, which are directly adjacent to photovoltaic functional stack and faceplate, block and are not harmed by ions that may diffuse out of glass and insulate current-carrying metallic components against corrosive ionic currents. The solar panel passes certification tests required by applicable industrial quality and safety standards organizations. The geometry and arrangement of coating layers are optimized for known, required test conditions which are reasonably believed to simulate long-term outdoor exposure. The large-area, durable and with long life expectancy solar panel has minimized production cost. All of the component materials of multilayer protective coating are readily available at low cost and may be applied by standard commercial methods as part of a continuous process.    DETAILED DESCRIPTION - An optoelectronic device comprises:    (1) a substrate (220) transparent to a range of operating wavelengths;    (2) functional stack (230) capable of converting light into electricity on substrate, and having electrical contact(s) (240) with conductive connection tab coupled to each and defining a border zone (260) on substrate between edge(s) of functional stack and edge(s) of substrate;    (3) barrier layer including inorganic films on substrate to cover a portion of functional stack and border zone;    (4) envelope layer including polymer films on substrate to cover a portion of barrier layer, border zone and edges of substrate; and    (5) electrical connector connected to each of conductive connection tabs.    Inner and outer barrier films are highly electrically insulating, chemically inert, impermeable to moisture, chemicals and ions, and insensitive to long-term temperature and humidity fluctuations and prolonged exposure to electric fields and UV light. The inner barrier film also is corrosion resistant, and is silicon carbide or silicon nitride. The outer barrier film comprises a silicon oxide. An inner envelope layer is electrically insulating; elastically absorbs mechanical shocks; mechanically relieves adjacent rigid materials from external compression, tension, bending and torsion stresses; elastically responds to differential thermal expansion of other materials in the device; and is insensitive to long-term temperature and humidity fluctuations and prolonged exposure to electric fields and UV light. The polymer films comprises a polymer including acrylic, siloxane, urethane, polyester, epoxy, fluoropolymer and/or their modified derivatives. An INDEPENDENT CLAIM is included for a method of protectively coating back and edges of an optoelectronic device built as a functional stack on transparent substrate.    DESCRIPTION OF DRAWING(S) - The drawing shows a simplified horizontal cross-sectional view of a substrate and functional stack, illustrating a border zone around edges or perimeter of functional stack.    Substrate (220)    Functional stack (230)    Electrical contact (240)    Border zone (260)    Coating stack (300)