Solar Panel Application With the development of solar energy industry, a variety of related components are increasingly becoming the hot topic of the industry. Packaging materials in solar modules have always been the most important material except silicon wafers, including glass, film, backplane, aluminum frame and silicone. Which because the backplane of the main material has been monopolized by foreign companies, in 07,08 was in short supply, so the backplane is also the most compelling packaging materials.
Common backplanes can be divided into TPT, TPE, PET and PET / polyolefin structure. Wherein T is a polyfluoroethylene (PVF) film of DuPont, Inc. under the trade name Tedlar. P refers to the biaxially stretched polyethylene terephthalate film, PET film, also known as polyester film or polyester film. E refers to ethylene-vinyl acetate resin EVA. Polyolefin refers to a variety of carbon-carbon structure as the main chain of plastic. In each of the indicated structure between the use of the appropriate adhesive bonding from the solar cell backplane.
To clarify the performance of solar cell backplane, we must first clear the performance of various fluorine materials. At present the most used fluorine plastic film for the PVF film. International production of PVF suppliers is very small, in addition to the United States DuPont, there are reports that China's blue sky environmental protection and dawn of the chemical industry have a small batch production. Such as chemical stability, water resistance, thermal stability, etc. are not as good as other fluorine plastic; the other hand, PVF processing is very troublesome, its melting point and decomposition point is very close to the extrusion film need to add latent solvent or copolymerization modification, This gives the membrane quality control and solvent recovery have brought a very high demand. Before the large number of solar panels used in front, PVF is mainly to promote the field of aluminum alloy building materials protection, pesticide packaging coatings. As DuPont first to promote its use in the solar cell backplane protection, with the recent surge in demand for Solar Panel Application, Tedlar demand also increased, and even in short supply.
Currently used in the transmission of conductive materials for the metal oxide, such as indium tin oxide (indium tinoxide, ITO), fluoride tin oxide (fluorine tin oxide, FTO), commonly known as conductive glass.Although the conductive glass is widely used in the field of solar cells, However,Solar Panel Application conductive glass has some drawbacks, such as ITO metal ions in the spontaneous diffusion, conductive glass on the infrared spectrum has a strong absorption and poor thermal conductivity of conductive glass.In addition, the conductive glass as a solar cell electrode , Need to be plated with a layer of platinum on its surface to enhance its conductivity, which greatly increases the cost of preparation. The above disadvantages restrict the development of solar cells with conductive glass as window electrode materials, and there is a great need for a low-cost material that can replace conductive glass or replace platinum to promote the industrialization of solar cells.As a kind of ultra- Good conductivity and good electrical properties of the conductor material, a metal oxide electrode is a better alternative material.Currently on the graphene as a translucent conductive electrode alternatives for the replacement of DSSC light anode light ITO / FTO, ITO / FTO for electrode plating, and ITO / FTO for organic polymer solar cell (OPSC).
The main structure of DSSC consists of three parts: the working electrode, the electrolyte and the counter electrode. The working electrode is composed of a porous semiconductor thin film on the transparent conductive substrate, and the working electrode is prepared by using DSSC as the transparent electrode. And then absorb the dye molecules in the porous film.The electrolyte can generally be liquid, it can be solid or quasi-solid. The electrode is usually platinum-plated ITO / FTO. DSSC works is adsorbed on the semiconductor film dye molecules After absorbing sunlight,Solar Panel Application from the ground state transition to the excited state: D + hv → D *; excited electrons are rapidly injected into the conduction band (CB) of the nanocrystalline crystal: D * → D + + e- (CB) The electrons in the conduction band reach the counter electrode via the external circuit: e- (CB) → e-; 3 I - ions diffuse to the electrode to get electrons: the continuous cycle of these reactions eventually achieves the photovoltage effect.
(A) dip coating is a commonly used method for preparing a thin film material. The main process comprises the following steps: (1) immersing the base material in the membrane material solution or the precursor solution; (2) controlling the speed pulling (3) the film coated on the substrate is dried or sintered, etc. Wang et al.  under the protection of H2 or Ar atmosphere, Graphene oxide, GO), and then the impregnation method was used to prepare the graphene thin layer material on the hydrophilic quartz sheet by controlling the temperature of the graphene solution and the number of times of impregnation, and the properties were tested. When the thickness of the film is (10.1 ± 0.76) nm, the sheet resistance is (1.8 ± 0.08) kΩ / □, and it still has good light transmittance in the infrared band, which is not comparable to ITO / FTO. The photoelectric conversion efficiency (0.26%) of the DSSC using this graphene as the light-transmitting electrode is lower than that of the FTO-based battery (0.84%). The low battery efficiency is mainly due to the large resistance of the graphene film, resulting in excessive battery series resistance ,Solar Panel Application Affecting the photoelectric conversion efficiency of the battery Although the electrode material prepared by this method did not improve the efficiency of the sensitized cell, the feasibility of graphene as a translucent conductive electrode was verified.
Although the impregnation method is easy to operate, but its operating conditions more difficult to control even in the case of uniform lift, the role of gravity will also cause uneven film thickness, to follow-up graphene film electrical properties of the study to bring some obstacles.
(B) spin coating A material solution or precursor solution which is added to the surface of the flat substrate is uniformly coated on the entire surface of the substrate by a centrifugal force generated by high-speed rotation, and after the drying or sintering process, And the uniformity of the film is better than that of the impregnation method by controlling the rotation speed of the substrate by controlling the rotation speed of the substrate, and the method of spin coating is used at room temperature The polystyrene and polystyrene sulfonic acid-doped ethylene composite was coated on ITO glass to prepare DSSC counter electrode with a surface film thickness of about 60 nm,Solar Panel Application a visible light transmittance greater than 80%, and a higher The DSSC efficiency was 4.5%, and the DSSC efficiency of platinum-coated ITO glass as a control was 6.3% as a control, and the reason why the photoelectric conversion efficiency was low was that the method The electrical properties of the prepared graphene films are still defective, and the conduction velocity and electrical conductivity of the electrons have yet to be further improved. Watcharotone mixes the GO solution with the silica sol, A method of spin coating is applied to a hydrophilic treated SiO2 / Si substrate,Solar Panel Application followed by reduction of GO and subsequent heat treatment to obtain a graphite / silicon composite material which is transparent and has good conductivity. Simple, easy to operate, can be prepared in the insulating glass substrate composite material to replace the ITO material, effectively reducing the ITO as part of the production costs of photovoltaic devices.There are also studied by spin coating on flexible transparent polymer (Reducedgrapheme oxide, RGO) film is coated and applied to a flexible solar cell.