CROSS REFERRENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to Chinese patent application No. 201220653796.7, filed on November 30, 2012, and entitled "Optical Component and Photovoltaic Device", the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

[0002] The present disclosure generally relates to optical material field, and more particularly, to an optical component and a photovoltaic device.

BACKGROUND

[0003] Generally, when light transmits from a first medium to a second medium, a portion of the light may change the propagation direction at the interface between the two mediums and return to the first medium. This phenomenon is known as light reflection. Furthermore, the strength of the light reflection at the interface between the different mediums usually increases with the difference between the refractive indexes of the different mediums.

[0004] Reducing light reflection in devices, such as a photovoltaic device or a display, has been a research focus. When lights transmit into a substrate, it is found by those skilled in the art that an antireflection layer may be formed on the substrate to reduce light reflection. Especially, when the antireflection layer meets the following requirements: the refractive index of the antireflection layer equals to the square root of a product of refractive indexes of the air and the substrate (a refractive indexes matching condition), and the thickness of the antireflection layer equals to one fourth of the light wavelength (a thickness matching condition), the antireflection layer may reduce reflection of lights having the wavelength effectively. Currently, the antireflection layer may be an antireflection layer with moth-eye structure, a porous silicon oxide layer, or a multi-layer antireflection coating including high refractive index material and low refractive index material alternatively stacked, etc.

[0005] However, the conventional antireflection layers mentioned above are usually not provided with the property of contamination resistance. Typically, to make a photovoltaic device or a display be contamination-resistant, the antireflection layer needs to be coated with an additional layer, such as a low surface energy layer, which may adversely influence the antireflection effect.

SUMMARY

[0006] In light of the problems mentioned above, embodiments of this disclosure provide an antireflection film having property of contamination resistance. In another aspect, a contamination-resistant layer may be formed on an antireflection film, which may not cause substantial degradation of antireflection effect.

[0007] In one embodiment, an optical component is provided, which may include: a substrate; and a first antireflection layer which comprises a packing medium and a particle array comprising a plurality of particles, wherein the packing medium fills at least in part voids formed between the plurality of particles.

[0008] It is found that the first antireflection layer having the above-mentioned structure may have properties of both antireflection and contamination resistance.

[0009] In some embodiments, the optical component further comprises a second antireflection layer between the substrate and first antireflection layer.

[0010] In some embodiments, the second antireflection layer may include a plurality of silica microspheres and voids formed between the plurality of silica microspheres. In some embodiments, the plurality of silica microspheres may have a diameter ranging from lOnm to 20nm.

[0011] In some embodiments, the plurality of particles may be microspheres which have a diameter ranging from 80nm to 250nm.

[0012] In some embodiments, the packing medium may include a plurality of nanoparticles.

[0013] In some embodiments, the plurality of particles and the plurality of nanoparticles may be one or more selected from silica microspheres, titanium oxide microspheres, aluminum oxide microspheres and zirconium oxide microspheres.

[0014] In some embodiments, the plurality of nanoparticles may include silica microspheres having a diameter ranging from 7nm to 12nm, and the plurality of particles may include silica microspheres having a diameter ranging from 80nm to 250nm.

[0015] In some embodiments, the packing medium may fill at least 90% of the voids formed between the plurality of particles.

[0016] In some embodiments, the plurality of particles and the packing medium may be integrated as a whole.

[0017] In one embodiment, a photovoltaic device is provided, which may include an optical component provided in embodiments of the disclosure, wherein the optical component comprises a transparent substrate; and a solar cell, located on a side of the substrate on which the first antireflection layer is not located.

[0018] The above descriptions summarize features and configurations of this disclosure. And additional features may be provided hereinafter, which provide embodiments of subject matter defined in the appended claims. The specific features and acts described above may be used to implement the claims. It should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts, to fulfill the same purpose as disclosed herein. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] A further understanding of the nature and advantages of various embodiments may be realized by reference to the following figures;

[0020] FIG. 1 schematically illustrates a cross-sectional view of an optical component 100 according to one embodiment of the present disclosure;

[0021] FIG. 2 schematically illustrates a cross-sectional view of an optical component 200 according to one embodiment of the present disclosure;

[0022] FIG. 3 schematically illustrates a cross-sectional view of an optical component 300 according to one embodiment of the present disclosure;

[0023] FIG. 4 schematically illustrates a cross-sectional view of an optical component 400 according to one embodiment of the present disclosure;

[0024] FIG. 5 schematically illustrates a cross-sectional view of an optical component 500 according to one embodiment of the present disclosure;

[0025] FIG. 6 schematically illustrates a flow chart of a method for forming an optical component according to one embodiment of the present disclosure;

[0026] FIG. 7 schematically illustrates a flow chart of a method for forming an optical component according to another embodiment of the present disclosure;

[0027] FIG. 8 schematically illustrates a flow chart of a process S300 shown in FIG. 7 according to one embodiment of the present disclosure;

[0028] FIG. 9 schematically illustrates a flow chart of a process S200 shown in FIG. 6 or FIG. 7 according to one embodiment of the present disclosure;

[0029] FIG. 10 schematically illustrates a flow chart of a process S200 shown in FIG. 6 or FIG. 7 according to another embodiment of the present disclosure; [0030] FIG. 11 schematically illustrates a transmission spectrum of an exemplary optical component 100 according to one embodiment of the present disclosure; and

[0031] FIG. 12 schematically illustrates a transmission spectrum of an exemplary optical component 200 according to one embodiment of the present disclosure.

[0032] Unless expressly stated to the contrary, like reference numerals and labels in different figures refer to similar elements. Further, the figures are drawn to emphasize specific features relevant to the exemplary embodiments, so elements in the figures may not be drawn to scale. For clarity of illustration, a sub-label may be associated with a reference numeral to denote one of mutiple similar components, materials or steps.

DETAILED DESCRIPTION

[0033] The disclosure will be described in detail with reference to certain embodiments. It will be understood by those skilled in the art that various changes may be made without departing from the spirit or scope of the disclosure. Accordingly, the present disclosure is not limited to the embodiments disclosed.

[0034] For the purpose of illustration, a device provided in embodiments of the present disclosure is described with reference to a method for forming the same device. It should be noted that the device is independent from the method. In other words, the device provided in embodiments of the present disclosure may be formed with other methods, and the method provided in embodiments of the present disclosure is not limited to obtain the device disclosed in the embodiments.

[0035] FIG. 6 schematically illustrates a flow chart of a method for forming an optical component according to one embodiment of the present disclosure.

[0036] First, in SI 00, a substrate is provided. The substrate may be made of any suitable material, including but not limited to, glass, metal, polymer or semiconductor. The substrate may have any suitable shape, such as a flat surface, a curved surface, etc.

[0037] In S200, a first antireflection layer is formed. The first antireflection layer includes a packing medium and a particle array including a plurality of particles. The packing medium fills at least in part voids formed between the plurality of particles.

[0038] An optical component 100 shown in FIG. 1 may be formed by using the method shown in FIG. 6.

[0039] Referring to FIG. 1, the optical component 100 includes a substrate 120 and a first antireflection layer 140 formed thereon. The first antireflection layer 140 includes a particle array including a plurality of particles 142, and a packing medium 144 which fills voids formed between the plurality of particles 142 in part.

[0040] Specifically, the packing medium 144 includes a plurality of nanoparticles, each of which has a diameter significantly less than that of the particles 142. That is, the first antireflection layer 140 has a heterogeneous particle structure.

[0041] It is found that the first antireflection layer 140 having a heterogeneous particle structure has properties of both antireflection and contamination resistance. That is, there is no need to coat a contamination-resistant layer on the antireflection layer, which may avoid potential degradation of antireflection effect caused by the contamination-resistant layer.

[0042] The phenomenon mentioned above may be interpreted as follows. The particle array formed by large-size particles 142 has a suitable roughness, which makes the heterogeneous particle structure have the capability of resisting contamination. And the small-size nanoparticles 144 can avoid a sudden change of the refractive index at the interface between the heterogeneous particle structure and the substrate, which makes the heterogeneous particle structure have the antireflective property. Specifically, the refractive index of the first antireflection layer 140 changes gradually from the top surface of the nanoparticles 144 to the interface between the heterogeneous particle structure and the substrate 120. Otherwise, if there are no nanoparticles 144, the refractive index may change sharply at the interface between the particles 142 and the substrate 120.

[0043] It should be noted that the term "particle array", as used herein, is intended to refer to a single-layer array including the plurality of particles 142. However, an array having a local multi-layer structure, such as a double layer which may appear due to limited experiment condition, also belongs to the scope of the term "particle array" disclosed herein.

[0044] In some embodiments, the arrangement of the plurality of particles 142 may be ordered or disordered. In some embodiments, the plurality of particles 142 may include, but not limited to, silicon oxide, titanium oxide, aluminum oxide or zirconium oxide. In some embodiments, the plurality of particles 142 may have a shape of sphere, regular dodecahedron, triacontahedron or irregular polyhedron, or have any other suitable shape. The size of the particles 142 may be selected according to the thickness of the conventional single-layer antireflection layer, such as a magnesium fluoride layer, a porous silicon oxide layer. When the plurality of particles 142 are microspheres which are configured closely and voids formed between the plurality of particles is filled with the plurality of nanoparticles 144, the particles 142 may have a diameter substantially equal to the thickness of the single-layer antireflection layer. When the plurality of particles 142 are microspheres which are configured closely and the degree of filling for the voids formed between the plurality of particles exceeds 90%, the particles 142 may have a radius substantially equal to the thickness of the single-layer antireflection layer. The antireflection layer having a heterogeneous particle structure provided in embodiments of this disclosure may have properties of both antireflection and contamination resistance. In some embodiments, the particles 142 may have a diameter ranging from about 80nm to about 250nm.

[0045] In light of the above description, the first antireflection layer 140 described in the embodiments of this disclosure has a heterogeneous particle structure, which is provided with properties of both antireflection and contamination resistance.

[0046] It also should be noted that the term "voids formed between the plurality of particles", as used herein, is intended to refer to spaces between the plurality of particles which may have a height no greater than that of the particles, such as 80%, 70%, 60%, 50% height of the particles. When the plurality of nanoparticles 144 exceed the voids formed between the plurality of particles, it may cause degradation of antireflection effect of the antireflection layer. Referring to FIG. 1, the nanoparticles 144 fill the voids to a height of about 50% of the height of the particles 142, which may achieve a satisfactory effect of antireflection and contamination resistance.

[0047] Hereunder, the process S200 shown in FIG. 6 will be described in conjunction with FIG. 9.

[0048] In S210, a first suspension liquid, which includes silica microspheres having a diameter ranging from 80nm to 250nm, is provided. For example, silica microspheres having a diameter of lOOnm may be dispersed in ethanol, so as to obtain a suspension liquid wherein a mass ratio of the silica microspheres to the suspension liquid is about 1%.

[0049] In S220, the first suspension liquid is coated on the substrate 120 and the substrate 120 coated with the first suspension liquid is dried. Spinning coating, dip coating, spraying coating, or other suitable methods may be used to coat the substrate 120 with the first suspension liquid.

[0050] In S230, a second suspension liquid, which includes silica microspheres having a diameter ranging from 7nm to 12nm, is provided. For example, silica microspheres having a diameter ranging from lOnm to 12nm may be dispersed in ethanol, so as to obtain a suspension liquid wherein a mass ratio of the silica microspheres to the suspension liquid is about 0.5%.

[0051] In S240, the second suspension liquid is coated on the substrate 120 and the substrate 120 coated with the second suspension liquid is dried. Spinning coating, dip coating, spraying coating, or other suitable methods may be used to coat the substrate 120 with the second suspension liquid.

[0052] In some embodiments, the process S200 may further include, such as, annealing the substrate for two hours at a temperature of about 480°C after coating the substrate with the second suspension liquid, so as to enhance mechanical strength of the first antireflection layer 140.

[0053] It should be noted that examples shown in FIG. 9 are presented for exemplary purposes only, and the present disclosure should not be limited thereto. The process S200 may be implemented with any other suitable methods. For example, after the substrate is coated with the first suspension liquid and dried, the packing medium may be formed by Chemical Vapor Deposition (CVD), or formed through dipping and sintering.

[0054] An optical component 100 provided in embodiments of the present disclosure will be described hereinafter.

[0055] The optical component 100 may be formed according to the method shown in FIG. 9: providing a glass substrate, using silica microspheres having a diameter of about lOOnm as the particles 142, and using silica microspheres having a diameter ranging from about lOnm to about 12nm as the nanoparticles 144 which fill the voids formed between the plurality of particles 142 to a height about 50% of the height of the particles 142. Transmission spectra of the optical component 100 are shown in FIG. 11, which are illustrated by a full line labeled C910 and a dotted line labeled C920, respectively. The full line C910 denotes a transmission spectrum of the optical component 100 obtained after the optical component 100 has just been formed. The dotted line C920 denotes a transmission spectrum of the optical component 100 which has been placed on a housetop at an angle of 45° for two days. By contrast,, transmission spectra of a bare glass before and after being placed on a housetop at an angle of 45° for two days are also provided, which are marked with a full line labeled C930 and a dotted line labeled C940, respectively. In FIG. 11, the Y axis represents light transmittance (as a percent), and the X axis represents wavelength (in nanometers).

[0056] Referring to FIG. 11, the light transmittance of the optical component 100 having the first antireflection layer 140 is substantially increased compared with that of the bare glass and changes very little after the optical component 100 having the first antireflection layer 140 is placed on the housetop for two days. While the maximum value of the light transmittance of the bare glass changes from 91.8% to 91.3%, after it is placed on the housetop for two days. That is, the first antireflection layer 140 have properties of both antireflection and contamination resistance.

[0057] FIG. 7 schematically illustrates a method for forming an optical component according to another embodiment of the present disclosure. Compared with the embodiments shown in FIG. 6, a process S300 is added between the processes SI 00 and S200 in the embodiment shown in FIG. 7.

[0058] In S300, a second antireflection layer is formed, which may be a conventional antireflection layer, or may be developed after the present application is filed. The second antireflection layer may include, but not limited to, a porous silicon oxide layer, a magnesium fluoride layer, a mesoporous silicon oxide particles layer, or a film with moth-eye structure.

[0059] An optical component 200 shown in FIG. 2 may be formed with the method shown in FIG. 7.

[0060] Referring to FIG. 2, compared with the optical component 100, the optical component 200 may further include a second antireflection layer 160 formed between the substrate 120 and the first antireflection layer 140.

[0061] It is found that, by forming the first antireflection layer 140 having a heterogeneous particle structure on the second antireflection layer 160, not only the contamination-resistant property can be achieved, but also the antireflection effect of the second antireflection layer 160 may not be affected substantially, which thereby may overcome or alleviate the problem of degradation of antireflection effect which may be caused by other contamination-resistant layers.

[0062] Hereunder, the process S300 shown in FIG. 7 will be described in conjunction with FIG. 8.

[0063] In S310, a suspension liquid including silica microspheres is provided. For example, silica microspheres having a diameter ranging from lOnm to 20nm may be dispersed in water to obtain a suspension liquid wherein a mass ratio of the silica microspheres to the suspension liquid is about 25%. The suspension liquid is then diluted with ethanol to have a mass ratio of about 0.5%.

[0064] In S320, a substrate is dipped into the suspension liquid.

[0065] In S330, the substrate is drawn out of the suspension liquid. For example, the substrate may be drawn out of the suspension liquid at a speed of 3mm/s.

[0066] It should be noted that examples shown in FIG. 8 are presented for descriptive purpose, but not intended to be limiting. The process S300 may be performed to form the suitable second antireflection layer 160 with any suitable method. For example, a magnesium fluoride layer may be formed with Magnetron Sputter Plating.

[0067] An optical component 200 provided in embodiments of the present disclosure will be described hereinafter.

[0068] Firstly, the second antireflection layer 160 is formed according to the method shown in FIG. 8. Specifically, a glass substrate is provided. Silica microspheres having a diameter ranging from lOnm to 20nm are dispersed in water to obtain a suspension liquid having a mass ratio of about 25%. The suspension liquid is then diluted with ethanol to have a mass ratio of about 0.5%. The glass substrate is dipped into the diluted suspension liquid. Then the glass substrate is drawn out of the suspension liquid and is dried in air. Then, the first antireflection layer 140 is formed according to the method shown in FIG. 9. Specifically, silica microspheres having a diameter of about lOOnm are used as the particles 142, and silica microspheres having a diameter ranging from lOnm to 12nm are used as the nanoparticles 144 which fill the voids formed between the plurality of particles 142 to a height of about 50% of the height of the particles 142.

[0069] The optical component 200 obtained in this way may have a transmission spectrum illustrated by a curved line labeled C110 shown in FIG. 12. By contrast, a curved line C120 denotes a transmission spectrum of a bare glass (which is illustrated by a thumbnail image on the upper right); a curved line labeled C130 denotes a transmission spectrum of an optical component having a second antireflection layer 160, but without a first antireflection layer 140 (which is illustrated by a thumbnail image on the lower left); and a curved line labeled CI 40 denotes a transmission spectrum of an optical component having a second antireflection layer 160, and a first antireflection layer 140 which has a plurality of large-size particles 142, but has no nanoparticles 144 (which is illustrated by a thumbnail image on the lower right). In FIG. 12, the Y axis represents light transmittance (as a percent), and the X axis represents wavelength (in nanometers).

[0070] Referring to FIG. 12, compared with the optical component having the second antireflection layer 160, but without the first antireflection layer 140 (corresponding to the curved line labeled CI 30), the antireflection effect of the optical component 200 (corresponding to the curved line labeled CI 10) is not substantially degraded. Instead, the antireflection effect is improved in the wavelength range of 400nm to 2000nm, which makes the optical component 200 advantageous in applications on a photoelectric device which works in the wavelength range of 400nm to 2000nm.

[0071] Compared with the optical component in which the first antireflection layer 140 has a plurality of large-size particles 142, but has no nanoparticles 144 (corresponding to the curved line labeled C140), the optical component 200 (corresponding to the curved line labeled CI 10) has better antireflection effect over the whole wavelength range.

[0072] FIG. 10 schematically illustrates the process S200 shown in FIG. 6 or FIG. 7 according to another embodiment of the present disclosure.

[0073] The process S200 may further include S250: annealing the substrate to make the silica microspheres in a molten state.

[0074] An optical component 300 shown in FIG. 3 may be obtained according to the method illustrated in FIG. 10.

[0075] Referring to FIG. 3, compared with the first antireflection layer 140 of the optical component 100 or 200, a packing medium 344 of a first antireflection layer 340 of the optical component 300 fills at least 90% of the voids formed between the plurality of particles 142, and the plurality of particles 142 together with the packing medium 344 are integrated as a whole. Similar to the first antireflection layer 140, the first antireflection layer 340 has properties of both antireflection and contamination resistance. Other than the advantages of the first antireflection layer 140, the first antireflection layer 340 may further prevent water or impurities from entering thereinto.

[0076] It should be noted that the packing medium 344 may be formed with, but not limited to, the method shown in FIG. 10. For example, the packing medium 344 may be formed by Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), dipping and sintering, or any other suitable method. [0077] FIG. 4 schematically illustrates a cross-sectional view of an optical component 400 according to one embodiment of the present disclosure. In the optical component 400, a packing medium 444 may include one or more selected from porous silicon oxide, porous titanium oxide, porous aluminum oxide and porous zirconium oxide. Similar to the first antireflection layer 140, a first antireflection layer 440 of the optical component 400 has the properties of both antireflection and contamination resistance as well.

[0078] It should be noted that the first antireflection layer 440 may be formed with any appropriate method. In some embodiments, tetraethoxysilane (TEOS) collosol and silica particles 142 may be mixed, and the substrate 120 may be coated with the mixture by spin coating. Then a heat treatment may be performed on the substrate to obtain the first antireflection layer 440, where the packing medium 444 includes porous silicon oxide.

[0079] FIG. 5 schematically illustrates a cross-sectional view of an optical component 500 according to one embodiment of the present disclosure. Referring to FIG. 5, the optical component 500 includes a transparent compact layer 580, which is disposed between the first antireflection layer 440 and the substrate 120. The transparent compact layer 580 may include one or more materials selected from a group consisting of silicon oxide, titanium oxide, aluminum oxide and zirconium oxide. The transparent compact layer 580 may prevent outward diffusion of alkali metal ions or alkali earth metal ions from the substrate 120.

[0080] It should be noted that the transparent compact layer 580 can be combined with other embodiments of the disclosure. For example, the transparent compact layer 580 may be provided between the first antireflection layer 140 and the substrate 120 of the optical component 100, or provided between the second antireflection layer 160 and the substrate 120 of the optical component 200, or provided between the first antireflection layer 340 and the substrate 120 of the optical component 300. [0081] In the above description, silica microspheres are taken as an example to illustrate the particles 142 and the nanoparticles 144. It should be noted that the particles 142 and the nanoparticles 144 may include titanium oxide microspheres, aluminum oxide microspheres or zirconium oxide microspheres. The particles 142 may include a material same as or different from that of the nanoparticles 144. The particles 142 may include one or more kinds of materials, and the nanoparticles 144 may also include one or more kinds of materials. The particles 142 and the nanoparticles 144 may have a shape of sphere, but not limited thereto. In some embodiments, the particles 142 and the nanoparticles 144 may have a shape of regular dodecahedron or triacontahedron, or irregular polyhedron, or any other suitable shape.

[0082] Although the present disclosure has been disclosed above with reference to preferred embodiments thereof, it should be understood that the disclosure is presented by way of example only, and not limitation. Those skilled in the art can modify and vary the embodiments without departing from the spirit and scope of the present disclosure.