Patent Application
20100101641
The present invention generally relates to a solar cell material and a method for manufacturing the same and, more particularly, to a solar cell coating and a method for manufacturing the solar cell coating by mixing different materials.
As the amounts of conventional resources such as electricity, coal and petroleum are limited, the resource problems have become a bottleneck of economic growth. More and more countries have launched researches on solar energy as a potential motive force for economic development. The solar energy, as a renewable energy resource, has attracted tremendous amount of attention. The solar energy is realized using solar cells with less power consumption and environment friendliness. In recent years, with the increasing demand in the solar energy, the manufacturing technology has advanced significantly. Therefore, the solar energy has been the fastest developing industry.
In order to convert the solar energy into electrical energy, the solar cells are inevitable. The solar cell is a diode device with a p-n semiconductor junction, whereat the photoelectric effect is used to generate electricity. When a photon is absorbed on the surface of a diode to generate excitons, the built-in electric field in the depletion region at the p-n junction unbind the excitons to generate electrons and holes transmitted to respective electrodes to induce a current and thus construct a solar cell.
Because of the importance of the solar cell, lots of efforts have been made on the efficiency as well as manufacturing of the solar cell in a material aspect to achieve efficient and rapid carrier transport. For example, in “Solar Cells based on quantum dots: Multiple exciton generation and intermediate bands,” MRS BULLETIN, Volume 32, March 2007, by Antonio Luque et al., an n-type porous semiconductor titanium dioxide (TiO2) layer is formed on a conductive substrate. Generally, the porous titanium dioxide layer is formed by sintering titanium dioxide particles and depositing a p-type indium phosphide (InP) quantum dot material on the porous titanium dioxide to form a solar cell with a p-n junction. Moreover, in this paper, a quantum dot material such as cadmium selenide (CdSe) is mixed with hole-conductive polymer (poly(2methoxy, 5-(2′-ethyl)-hexyloxy-p-phenylenevinylene), referred to as MEH-PPV) and electron-conductive polymer to form a solar cell with a multi-layered p-n junction.
Moreover, in “Quantum Dot Sensitization of Organic-Inorganic Hybrid Solar Cells,” J. Phys. Chem. B 2002, 106, 7578-7580, by Robert Plass et al., a solar cell formed of a mixture of an organic material and an inorganic material is disclosed. Like Antonio Luque et al., Robert Plass et al. use high-temperature sintering to make titanium dioxide porous and then deposit lead sulfide (PbS) quantum dots on the TiO2 substrate by chemical vapor-phase deposition (CVD). Later, the TiO2 substrate with PbS quantum dots is dipped in a conductive organic material such as a p-type conductive organic material (for example, spiro-OMeTAD) or is coated with a p-type polymer material (for example, MEH-PPV). The conductive organic material, titanium dioxide and lead sulfide form p-n hetero-junctions therebetween.
In the above-mentioned prior arts, three materials with different energy levels are respectively overlapped to form an the active layer of a solar cell, which is time-consuming and labor-intensive. Therefore, there is need in providing a solar cell coating and a method for manufacturing the same to overcome the aforesaid problems.
It is an objective of the present invention to provide a solar cell coating and a method for manufacturing the same, wherein the solar cell coating is coated on a substrate to manufacture a solar cell. The method for manufacture the solar cell coating is characterized in that nano semiconductor materials are provided with different energy levels to be mixed with a conductive polymer to form a ladder structured band lineup to assist carrier transport. Nano materials and polymer with different energy levels can be solved at the same time and distributed uniformly in a solvent to form a liquid coating. The solar cell coating can be coated by dipping, spray or spin-coating to manufacture the active layer of a solar cell.
It is another objective of the present invention to provide a solar cell coating and a method for manufacturing the same, wherein the solar cell coating is coated on a substrate to manufacture a solar cell. The method for manufacture the solar cell coating is characterized in that nano semiconductor materials are provided with different energy levels to be mixed with a conductive polymer to form a ladder structured band lineup to assist carrier transport. Nano materials and polymer with different energy levels can be mixed by high-temperature milling to form a coating with flowability. The solar cell coating can be coated by dipping, spray or spin-coating to manufacture the active layer of a solar cell.
To achieve the foregoing objectives, in one embodiment, the present invention provides a solar cell coating, comprising: a conductive polymer material corresponding to a first highest occupied molecular orbit (HOMO) and a first lowest unoccupied molecular orbit (LUMO); a low bandgap material corresponding to a second HOMO and a second LUMO, the low bandgap material being mixed with the conductive polymer material so that the low bandgap material is coupled to the conductive polymer material and the second HOMO and the second LUMO have lower energy than the first HOMO and the first LUMO, respectively; and a semiconductor material corresponding to a third HOMO and a third LUMO, the semiconductor material being mixed with the conductive polymer material so that the semiconductor material is coupled to the low bandgap material and the second HOMO and the second LUMO have higher energy than the third HOMO and the third LUMO, respectively.
In another embodiment, the present invention provides a method for manufacturing a solar cell coating, comprising steps of: providing a solvent; and forming a mixture by adding a conductive polymer material, a low bandgap material and a semiconductor material to the solvent; wherein the conductive polymer material corresponds to a first highest occupied molecular orbit (HOMO) and a first lowest unoccupied molecular orbit (LUMO), the low bandgap material corresponds to a second HOMO and a second LUMO, and the semiconductor material corresponds to a third HOMO and a third LUMO; wherein the low bandgap material is coupled to the conductive polymer material and the second HOMO and the second LUMO have lower energy than the first HOMO and the first LUMO, respectively, and the semiconductor material is coupled to the low bandgap material and the second HOMO and the second LUMO have higher energy than the third HOMO and the third LUMO, respectively.
In another embodiment, the present invention provides a method for manufacturing a solar cell coating, comprising steps of: forming a mixture by mixing a conductive polymer material, a low bandgap material and a semiconductor material; and forming a liquid mixture with flowability by performing high-temperature milling on the mixture; wherein the conductive polymer material corresponds to a first highest occupied molecular orbit (HOMO) and a first lowest unoccupied molecular orbit (LUMO), the low bandgap material corresponds to a second HOMO and a second LUMO, and the semiconductor material corresponds to a third HOMO and a third LUMO; wherein the low bandgap material is coupled to the conductive polymer material and the second HOMO and the second LUMO have lower energy than the first HOMO and the first LUMO, respectively, and the semiconductor material is coupled to the low bandgap material and the second HOMO and the second LUMO have higher energy than the third HOMO and the third LUMO, respectively.
The objectives and spirits of several embodiments of the present invention will be readily understood by the accompanying drawings and detailed descriptions, wherein:
The present invention can be exemplified but not limited by various embodiments as described hereinafter.
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The semiconductor material 22 corresponds to a third highest occupied molecular orbit (HOMO) 222 and a third lowest unoccupied molecular orbit (LUMO) 221 and is mixed with the conductive polymer material 20. The semiconductor material 22 is coupled to the low bandgap material 21. The second highest occupied molecular orbit (HOMO) 212 and the second lowest unoccupied molecular orbit (LUMO) 211 have higher energy than the third highest occupied molecular orbit (HOMO) 222 and the third lowest unoccupied molecular orbit (LUMO) 221. The semiconductor material is a nano-scale organic semiconductor material or a nano-scale inorganic semiconductor material. The inorganic semiconductor material is an n-type nano-scale inorganic material. In the present embodiment, the inorganic material comprises titanium dioxide (TiO2), zinc oxide (ZnO) or tin dioxide (SnO2). The organic semiconductor material comprises polyvinylcarbazole and is not limited thereto.
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Accordingly, the present invention discloses a solar cell coating and a method for manufacturing the solar cell coating by mixing different materials so that the solar cell coating exhibits high capability in transporting carriers effectively to transmit the electrons and holes to respective electrodes rapidly. Therefore, the present invention is novel, useful, and non-obvious.
Although this invention has been disclosed and illustrated with reference to particular embodiments, the principles involved are susceptible for use in numerous other embodiments that will be apparent to persons skilled in the art. This invention is, therefore, to be limited only as indicated by the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 097140986 | Oct 2008 | TW | national |
