CN101244893A - Method for manufacturing reflection-preventing layer of glass substrate - Google Patents

Abstract

The invention discloses a method for decreasing the light reflection of film photovoltaic devices, and the photovoltaic device which takes glass as a substrate is immersed into liquid with glass beads, so as to lead the glass substance with sparse structure to deposit on the external surface of the substrate, and a film layer which has light refraction coefficient between that of air and glass is formed. The easy implemented anti-radiation layer making method is especially suitable for the production of photovoltaic components with large areas which uses glass as the substrate.

Description

The method for manufacturing reflection-preventing layer of glass substrate

Technical field

The invention belongs to the optical material scope, specially refer to the photoprocess means of solar photovoltaic device.

Background technology

Recent years, the development of photovoltaic cell and big area photovoltaic module has caused common people's extensive concern.Especially amorphous silicon hydride and nanocrystal silicon, they demonstrate great potential along with the widespread use of photovoltaic device in commercial and dwelling house facility.A distinguishing feature of producing thin film silicon photovoltaic device under temperature so lower below 260 ℃ is, the sedimentary semiconductor film relevant of big area with silicon with electrically contact rete and have premium properties.Simultaneously, use good sophisticated filming equipment and program, can make to industrialization template cheaply.Be applied to the laser scribing moulding process of the different films on the same glass substrate, allow a plurality of solar cell devices in film deposition process, directly to form the big area photovoltaic module of integrated form, reduced procedure of processing and also improved reliability of products.

For photovoltaic device, film photovoltaic device particularly, the key that makes its excellent property is to optimize the absorption of photoelectric conversion semiconductor layer to luminous energy, and reduces the optical loss in the device simultaneously.Can absorb luminous energy to greatest extent in very thin absorption layer, be the essential condition of high conversion efficiency.Here the hydrogenation thin film silicon of indication comprises the alloy firm of amorphous silicon hydride, hydrogenation nanocrystal silicon and these silicon materials and other element be combined into, the solar cell that the hydrogenation thin film silicon is constituted has the p-i-n structure usually, wherein p layer and n layer are sluggish " dead layers ", they set up a built-in electric field in non-adulterated i layer, thereby make photic current carrier by effective collection.The thickness of its absorption layer generally has only a hundreds of micron, is no more than about 2000 microns at most.P-i-n structure based on hydrogenated silicon film by utilizing is sandwiched in former and later two electrodes (electric contacting layer), and forms complete photovoltaic element.Electrode must have good transparency and electroconductibility before normally used, and it normally is made of transparent conductive oxide (TCO), such as thickness is the stannic oxide that is doped or the zinc-oxide film of 600-900 nanometer.Rear electrode is made of jointly a TCO and metallic film usually, and an one vital role is returned unabsorbed luminous reflectance among the p-i-n structure exactly.People had attempted improving absorption to light with various ways, comprising use coarse transparent before electrode.In addition, also use the very high back electrode of reflecting rate, and made unabsorbed light be got back in the battery by throwing again.Can not do very thickly for amorphous silicon battery absorption layer i layer, reason is the defective that this material has the light quality decay.So remarkable optical design has played decisive role for the efficiency of conversion of the thin-film solar cells as the silicon hydride.

Current modal solar photovoltaic device all is as its top protecting sheet or as the substrate of film photovoltaic device, because glass has good transparency, cost is low, and has good chemistry and mechanical stability by sheet glass.The optical refractive index of glass is about 1.53, and the specific refraction of air is 1, is 0.0439 at the luminous reflectance factor of glass and air interface, and promptly 4.4%, so should not be left in the basket in the reflected light loss of glass surface.For the efficiency of conversion that makes optoelectronic equipment reaches the highest, and reflected light obtains reducing to greatest extent, uses the way of vacuum plating usually at the skin of glass, plates one deck tapetum lucidum, such as MgF.But this way is difficult to be made on the big area substrate usually, and its employed expensive processing units and process are unfavorable for large batch of production.The optical refractive index of the uniform antireflection film an of the best is 1.24, and it is the geometrical mean of the optical refractive index of air and glass substrate.

Summary of the invention

Based on above-mentioned consideration, the applicant has worked out primary and foremost purpose of the present invention: provide a high efficiency antireflection film cheaply, to reduce the luminous reflectance factor of glass and air interface.

Further purpose of the present invention is that improving with glass is the efficiency of conversion of the solar photovoltaic device of top board.

In order to achieve the above object, the present invention adopts a kind of simple and easy to do reflective technology that can be plated on the large-area glass plates, its way is exactly that little glass sphere is put in the solution that has adhesion agent, and when glass substrate is placed in the solution, some glass sphere will deposit to glass surface.Owing between the glass sphere air clearance (hole is arranged) is arranged, so the density of " film " that these glass spheres are formed is littler many than sheet glass.Therefore its optical refractive index is lower than sheet glass, just in time is between glass and air, because this material itself is formed by glass and air mixed exactly.So effectively having played of the sparse glass substance of one deck increased to the effect of higher numerical value optical refractive index very stably by lower numerical value like this, thereby avoided sudden variation, just avoided the effectively mutagenicity of light reflex interface.

Description of drawings

The present invention will be further described below in conjunction with drawings and Examples.

Accompanying drawing has shown a laminate structure with thin-film solar cells of antireflection glass substrate.

Embodiment

Embodiments of the present invention should be carried out according to the purposes of indication sheet glass, and we are example with the photovoltaic template based on hydrogenated silicon film by utilizing only here.At first producing with glass by common mode is the film photovoltaic device of substrate, comprises the formation of back electrode.Use molten gel sedimentation (sol-gel) glass sphere to be plated to the top layer of glass substrate then.Specific practice is that the photovoltaic template is immersed the molten gel that contains glass beads and adhesion agent, and constantly stir molten gel or continuous moving substrate itself, thereby make glass beads adhere to the glass substrate appearance uniformly, then glass substrate is taken out from molten gel, under the depositing temperature that is not higher than semiconductor film in the photovoltaic device, heat-treat adhesion agent is solidified, to form the final low specific refraction rete that constitutes by glass beads and clearance.Its optical refractive index is determined by porosity, comprises the size of glass beads and the thickness of rete.In order to make anti-reflection effect the most remarkable, can repeatedly use the method that forms above-mentioned rete, and the big or small and/or density in solution of employed glass beads is all different in each implementation process, have the antireflection film of the edge of gradient thereby form a specific refraction, because the volume of air ratio (porosity) of this rete changes with thicknesses of layers perpendicular to the direction variation of glass baseplate surface.Like this can be so that the very mild numerical value from glass of the optical refractive index in this reflecting layer carry out the transition to the numerical value of air, thus minimum luminous reflectance obtained.

Used a film photovoltaic device of the present invention as shown in drawings, this device comprises successively: in the face of incident light anti-reflection layer 10; Glass substrate 1; The preceding electrode 2 that constitutes by transparent conductive oxide; P-I-N photovoltaic lamination 8 based on hydrogenated silicon film by utilizing; Second transparent conductive oxide 22 and have reflexive metallic membrane 45.

Claims (2)

1. glass anti-reflection layer, it is characterized in that: its forming process is that glass is immersed the molten gel that contains glass beads, make glass beads adhere to the glass substrate appearance uniformly, then glass substrate is heat-treated sticking power with the reinforcing glass bead.The top layer that is formed by glass beads has the optical refractive index between air and glass substrate, and the edge of this coefficient with gradient change perpendicular to the direction of glass baseplate surface, thereby plays effective antireflection effect in the glass air interface.

2. glass anti-reflection layer according to claim 1 is characterized in that: anti-reflection layer is applied in the preposition glass substrate of solar photovoltaic device or the outside surface in the face of sunlight of protector plate for glass.

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