CN204497253U - The thin-film solar cells of the many laminations of a kind of many knots - Google Patents

Abstract

The utility model discloses the many overlapping thin film solar batteries of a kind of many knots.At least one crystallite PIN junction of this battery, according to the order of depositional coating, deposits p-type amorphous layer, and deposit N-shaped amorphous layer after the crystallite intrinsic layer of described crystallite PIN junction after the p-type microcrystalline coating of described crystallite PIN junction.This solar cell can make up the thin-film solar cells microcrystal silicon defect of the many laminations of many knots, reduces the leakage current therefore caused, thus reaches the object promoting battery efficiency.Battery conversion efficiency can promote 1%-10%, and has good stability.

Description

The thin-film solar cells of the many laminations of a kind of many knots

Technical field

The utility model relates to a kind of structural design improving thin-film solar cells microcrystal silicon defect.

Technical background

The amorphous silicon membrane preparing function admirable is sent out from Spear and Lecomber glow discharge in 1975, after the Carlson D.E in RCA laboratory in 1976 and Wronski C.R utilizes amorphous silicon hydride to produce first non-crystal silicon solar cell, thin-film solar cells is born.The eighties in 20th century non-crystal silicon solar cell conversion efficiency and stability obtain important picture, area 0.5m ²conversion efficiency 5% amorphous silicon solar cell module is once the market mainstream at that time, the nineties in 20th century, the problem of poor stability of ground conversion efficiency was solved further, and lamination non-crystal silicon solar cell is developed, and becomes the new main flow on solar cell market gradually.But amorphous silicon thin-film solar cell also exists very large shortcoming, on the one hand, the conversion efficiency of battery is lower, and the product commercially produced only has 6% usually; On the other hand, amorphous silicon thin-film solar cell performance is stable not, and there is the attenuation effect of more serious light, these shortcomings constrain popularizing of amorphous silicon thin-film solar cell.

Microcrystalline silicon film has been adopted hydrogen PCVD since nineteen sixty-eight since 600 DEG C first preparation by Veprek and Maracek, people start there has been Preliminary study to its potential premium properties, until 1979, Usui and Kikuchi of Japan strengthens chemical vapour deposition technique by the method using plasma adding hydrogen, prepare doped microcrystalline silicon, people just study microcrystalline silicon materials and application in solar cells thereof gradually.1994, Switzerland m.J.Williams and M.Faraji team proposes to take microcrystal silicon as end battery first, and amorphous silicon is the concept of the laminated cell of top battery, and this battery combines the long-wave response of amorphous silicon good characteristic and microcrystal silicon and the advantage of good stability.At present, amorphous silicon/microcrystalline silicon tandem solar cell is generally acknowledged most important thin film solar technology, is the developing direction of the hull cell of most industrialization value.The amorphous silicon/microcrystalline silicon tandem battery component sample efficiencies of Mitsubishi heavy industrys in 2005 and Zhong Yuan chemical company reaches 11.1% (40cm × 50cm) and 13.5% (91cm × 45cm) respectively.Japanese Sharp company realizes amorphous silicon/microcrystalline silicon tandem solar cell industryization in September, 2007 and produces (25MW, efficiency 8% ?8.5%), Europe Oerlikon (Oerlikon) company announce in September, 2009 the most high conversion efficiency in its amorphous/crystallite lamination solar cell laboratory reach 11.9%, at 2010 6 in the solar cell exhibition " PVJapan 2010 " of Yokohama opening, Applied Materials (AMAT) announce that the conversion efficiency that the conversion efficiency of 0.1m × 0.1m module reaches 10.1%, 1.3m × 1.1m module reaches 9.9%.

At present, for adapting to industrialized development, the high-quality of microcrystalline silicon film is ensured while the technological difficulties of microcrystalline silicon deposition are to realize microcrystal silicon high speed deposition, because the crystallite dimension of microcrystal silicon, the base material of grain growth and growth all has strong impact to the performance of microcrystalline silicon film, thus affects the performance of whole battery performance.Be full of the compound that crack in microcrystal silicon and hole add charge carrier, and cause leakage current, seriously reduce Voc and FF value.2008, Python team points out to only have and can produce so-called " slight crack " when microcrystal silicon backing material is V-shape, therefore when they propose backing material to be prepared into the U-shaped tended towards stability, " slight crack " fades away, but this method requires higher to hatching layer or p layer, in commercially produced product, be more difficult to the surface topography controlling microcrystalline silicon intrinsic layer deposition substrate.

Utility model content

The technical problems to be solved in the utility model is, become large extruding gradually for silicon microcrystal grain growth and produce the blemish such as slight crack gap and breach, a kind of many knot many laminated silicon-base films solar cells making up microcrystal silicon growth defect are proposed, this battery can make up microcrystal silicon growth defect, effectively can cover slight crack gap and blemish that grain growth extrudes formation mutually, intrinsic microcrystalline silicon face is flattened cunning, the crystallite dimension preventing subsequent film from depositing increases further, can reverse leakage current be reduced like this, increase open circuit voltage and fill factor, curve factor; On the other hand, use the amorphous layer of N-shaped doping higher than the intrinsic amorphous layer conductivity of undoped, and energy gap relative intrinsic amorphous silicon is lower, therefore interface resistance is relatively little.

For achieving the above object, the technical solution of the utility model is:

The many overlapping thin film solar batteries of a kind of many knots, comprise at least one crystallite PIN junction, according to the order of depositional coating, after the p-type microcrystalline coating of described crystallite PIN junction, deposit p-type amorphous layer, and deposit N-shaped amorphous layer after the crystallite intrinsic layer of described crystallite PIN junction.

Described crystallite PIN junction preferably includes microcrystal silicon PIN junction, microcrystalline silicon carbide PIN junction and crystallite SiGe PIN junction.

Described p-type amorphous layer can be the amorphous layer of doped with boron element.

Tell the amorphous layer that N-shaped amorphous layer can refer to Doping Phosphorus element.

The thickness of described p-type amorphous layer and described N-shaped amorphous layer is all preferably 2nm ~ 30nm.

Described p-type amorphous layer energy gap (Eg) is preferably 2 ~ 2.1eV, and refractive index (n) is preferably 3.55 ~ 3.65, and conductivity is preferably greater than 2.00x10 ^?6s/cm (Siemens/cm).

Described N-shaped amorphous layer energy gap (Eg) preferably must not more than 1.70eV, and refractive index (n) is preferably 4.60 ~ 4.80, and conductivity is preferably greater than 6.00x10 ^?3s/cm (Siemens/cm).

Make up a solar cell for many knot many overlapping thin film solar batteries microcrystal silicon defects, according to the order of depositional coating, preferably include following battery structure:

(1) substrate/TCO/p ?a ?Si _{1 ?x}ge _x/ i ?a ?Si _{1 ?x}ge _x/ n ?a ?Si _{1 ?x}ge _x/ central reflector layer/p ?a ?Si/i ?a ?Si/n ?a ?Si/ central reflector layer/p ?uc ?Si _{1 ?x}ge _x/ p-type amorphous layer/i ?uc ?Si _{1 ?x}ge _x/ N-shaped amorphous layer/n ?uc ?Si _{1 ?x}ge _x/ central reflector layer/p ?uc ?Si/p type amorphous layer/i ?uc ?Si/n type amorphous layer/n ?uc ?Si/ central reflector layer/p ?a ?SiC/i ?a ?SiC/n ?a ?SiC/ central reflector layer/p ?uc ?SiC/p type amorphous layer/i ?uc ?SiC/n type amorphous layer/n ?uc ?SiC/TCO/ antireflective coating;

(2) substrate/TCO/p ?a ?Si _{1 ?x}ge _x/ i ?a ?Si _{1 ?x}ge _x/ n ?a ?Si _{1 ?x}ge _x/ central reflector layer/p ?a ?Si/i ?a ?Si/n ?a ?Si/ central reflector layer/p ?uc ?Si _{1 ?x}ge _x/ p-type amorphous layer/i ?uc ?Si _{1 ?x}ge _x/ N-shaped amorphous layer/n ?uc ?Si _{1 ?x}ge _x/ central reflector layer/p ?uc ?Si/p type amorphous layer/i ?uc ?Si/n type amorphous layer/n ?uc ?Si/ central reflector layer/p ?uc ?SiC/i ?uc – SiC/p type amorphous layer/i ?uc ?SiC/n type amorphous layer/n ?uc ?SiC/TCO/ antireflective coating;

(3) substrate/TCO/p ?a ?Si _{1 ?x}ge _x/ i ?a ?Si _{1 ?x}ge _x/ n ?a ?Si _{1 ?x}ge _x/ central reflector layer/p ?a ?Si/i ?a ?Si/n ?a ?Si/ central reflector layer/p-type amorphous layer/i ?uc ?Si _{1 ?x}ge _x/ N-shaped amorphous layer/n ?uc ?Si _{1 ?x}ge _x/ central reflector layer/p ?uc ?Si/p type amorphous layer/i ?uc ?Si/n type amorphous layer/n ?uc ?Si/TCO/ antireflective coating;

(4) substrate/TCO/p ?a ?Si/i ?a ?Si/n ?a ?Si/ central reflector layer/p ?uc ?Si _{1 ?x}ge _x/ p-type amorphous layer/i ?uc ?Si _{1 ?x}ge _x/ N-shaped amorphous layer/n ?uc ?Si _{1 ?x}ge _x/ central reflector layer/p ?uc ?Si/p type amorphous layer/i ?uc ?Si/n type amorphous layer/n ?uc ?Si/TCO/ antireflective coating;

Wherein, the rete between tco layer and adjacent central reflector layer and between adjacent two central reflector layer is a knot, 0 < x < 1; "/" represent two-layer between interface; Substrate is glass, stainless steel or macromolecular material.

Rete between tco layer and adjacent central reflector layer and between adjacent two central reflector layer is a knot, often knot in each rete semi-conducting material used identical and form because adulterating difference pin knot; 0 < x < 1; "/" represent two-layer between interface; N ?represent electron type (N-shaped) semiconductor, i ?represent intrinsic semiconductor, p ?represent cavity type (p-type) semiconductor; A ?represent noncrystal, μ c ?represent crystallite.

Described p-type amorphous layer and described N-shaped amorphous layer by the one of C, Si, Ge or bi-material composition arbitrarily, can be such as a ?Si, a ?SiGe, a ?the material such as SiC.

Described p-type amorphous layer is the amorphous layer of doped with boron element or doped with boron element and the non-crystal composite layer of the unadulterated p/i of intrinsic or the amorphous layer with gradient concentration or structure doped with boron element.

Tell N-shaped amorphous layer and refer to the amorphous layer of Doping Phosphorus element or intrinsic is not adulterated and the non-crystal composite layer of the i/n of Doping Phosphorus element or refer to the amorphous layer of the Doping Phosphorus element with gradient concentration or structure.

Make up a method for many knot many overlapping thin film solar batteries microcrystal silicon defects, according to the order of depositional coating, adopt the thin-film solar cells of the many laminations of the many knots of PECVD depositing operation deposition, after having deposited p-type microcrystalline coating, deposit one deck p-type amorphous layer; And after deposition of microcrystalline intrinsic layer, deposit one deck N-shaped amorphous layer.

Such as: the described manufacture method making up many knot many laminated silicon-base films solar cells of microcrystal silicon growth defect is that using plasma strengthens chemical vapour deposition technique (PECVD) after p-type microcrystal silicon layer (p ?uc ?Si), deposits one deck p-type amorphous silicon layer, between microcrystalline silicon intrinsic layer (i ?uc ?Si) and N-shaped microcrystal silicon layer, one deck N-shaped amorphous layer is deposited.

Described N-shaped amorphous layer, it deposits the uniformity had on large area substrates, as at 1.1 × 1.3m ²substrate be divided into 15 × 13 dot matrix measure film thickness uniformity must not more than 15%;

Compared with prior art, technical advantage of the present utility model is:

The utility model can constant in the end battery intrinsic layer thickness and p-type microcrystal silicon layer pattern keeping amorphous silicon/microcrystalline silicon tandem solar cell while, reduce leakage current and defect state that the slight crack gap that causes due to silicon microcrystal grain abnormal growth and blemish cause, increase the fill factor, curve factor of end battery open circuit voltage and whole battery, thus improve the electricity conversion of whole battery, battery conversion efficiency can promote 1%-10%, and there is good stability, preparation and the actual volume industrial that can be applied to silicon-based film solar cells are produced.

Accompanying drawing explanation

Fig. 1 is the utility model example structure schematic diagram;

Fig. 2 is the utility model the first battery structure schematic diagram applicatory;

Fig. 3 is the utility model the second battery structure applicatory schematic diagram;

Fig. 4 is the utility model the third battery structure schematic diagram applicatory;

Fig. 5 is the utility model the 4th kind of battery structure schematic diagram applicatory;

Fig. 6 is the surface gap schematic diagram that in microcrystal silicon, grain growth produces;

Fig. 7 is the slight crack gap TEM sectional view existed in microcrystal silicon layer in laminated cell;

Fig. 8 is that the utility model has N-shaped amorphous layer and the IV curve of binode laminated cell not having N-shaped amorphous layer.

Embodiment

Below in conjunction with accompanying drawing, by embodiment, the utility model is described further.

The many overlapping thin film solar batteries of a kind of many knots, comprise at least one crystallite PIN junction, it is characterized in that, according to the order of depositional coating, after the p-type microcrystalline coating of described crystallite PIN junction, deposit p-type amorphous layer, and deposit N-shaped amorphous layer after the crystallite intrinsic layer of described crystallite PIN junction.

In the real case of amorphous silicon/microcrystal silicon binode laminated cell, solar battery structure as shown in Figure 1, comprising: substrate/TCO/p ?a ?Si/i ?a ?Si/n ?a ?Si/ central reflector layer/p ?uc ?Si/p type amorphous layer/i ?uc ?Si/n type amorphous layer/n ?uc ?Si/TCO/ antireflective coating;

The detailed process of preparing of above-mentioned application structure is as described below:

1. header board glass cleaning

Utilize industrialization cleaning machine, with alkaline proportioning cleaning agent cleaning substrate, rinsed with deionized water is also air-dry.

Electrode deposition before 2.TCO

In vacuum equipment, pass into DEZ with LPCVD method, B ₂h ₆with H ₂o react deposition B doping ZnO (BZO) material as front electrode, deposit thickness is 1500 ~ 1800nm;

Electrode laser segmentation (sub-battery forming process 1) before 3.TCO

Electrode before employing 355nm long wavelength laser segmentation TCO, for the circuit structure of sub-battery lays the foundation;

4. amorphous silicon top cell deposition

With the condition of 40.68MHz PECVD method 200 DEG C of underlayer temperatures deposition a ?Si:H push up battery, comprise PIN complete structure, alternative deposition Window layer, resilient coating etc. optimize rete, and incorporate processing technology of interface and improve; Top cell thickness is between 200 ~ 300nm.

5. central reflector layer deposition

With the central reflector layer of 40.68MHz PECVD method 200C underlayer temperature deposition 2 layers or multilayer 15 ~ 20nm on the battery n layer of top.

6. cell deposition at the bottom of microcrystal silicon

In microcrystalline silicon deposition chamber, with 40.68MHz PECVD method be that under the condition of 160 DEG C, on the substrate that deposited amorphous silicon top battery, (1) passes into SiH in temperature ₄, H ₂, TMB uses the operation pressure of 2 ~ 3mbar, the p-type microcrystal silicon doped layer of deposition about 1 ~ 20nm; (2) SiH is passed into ₄, H ₂, TMB uses the operation pressure of 0.5 ~ 2mbar, radio frequency power density 10 ~ 50mW/cm ², the p-type amorphous silicon doped layer of deposition about 2 ~ 30nm; (3) SiH is passed into ₄, H ₂mist, use the operation pressure of 2 ~ 4mBar, radio frequency power density 50 ~ 250mW/cm2, deposits about 800nm ~ 1000nm microcrystalline silicon intrinsic layer; (4) after microcrystalline silicon intrinsic layer, SiH is passed into ₄, H ₂, 2%PH ₃/ H ₂mist, uses the operation pressure of 0.5 ~ 2mBar, radio frequency power density 10 ~ 50mW/cm ², deposition one deck N-shaped amorphous covering layer, thickness range 2nm ~ 30nm; (5) after N-shaped amorphous covering layer, SiH is passed into ₄, H ₂, 2%PH ₃/ H ₂, CO ₂mist, uses the operation pressure of 0.5 ~ 2mBar, radio frequency power density 50 ~ 250mW/cm ², depositing n-type microcrystal silicon layer, thickness range 1 ~ 20nm.

7. silica-base film layer laser separation (sub-battery forming process 2)

The position of carving with reference to front one laser scribing offsets about 100um, adopts 532nm long wavelength laser segmentation silicon thin film, for the circuit structure of sub-battery lays the foundation;

8.TCO back electrode deposits

In vacuum equipment, pass into DEZ with LPCVD method, B2H6 and H2O react deposition B doping ZnO (BZO) material as back electrode, deposit thickness is 1500 ~ 1800nm;

9. silica-base film layer and TCO back electrode laser separation (sub-battery forming process 3)

The position of carving with reference to front one laser scribing offsets about 100um, and adopt 532nm long wavelength laser segmentation silicon thin film and TCO back electrode, such 3 road laser separation techniques complete, and the common basic circuit forming battery connects framework;

10. circuit connects

Based on the battery basic framework that laser scribing is formed, with conducting resinl, conductive strips are bonded to the both positive and negative polarity of battery, pass through welding bridge joint with friendship conductive strips vertical with it between conductive strips, form 3 groups of series parallel circuit structures, obtain low voltage performance.

11. cell package and parts assembling

Using EVA as encapsulation and back reflection layer material, encapsulate whole battery together with back-panel glass, and the parts such as terminal box are installed, complete performance test and roll off the production line.

Claims (8)

1. tie many overlapping thin film solar batteries one kind more, comprise at least one crystallite PIN junction, it is characterized in that, according to the order of depositional coating, after the p-type microcrystalline coating of described crystallite PIN junction, deposit p-type amorphous layer, and deposit N-shaped amorphous layer after the crystallite intrinsic layer of described crystallite PIN junction.

2. tie many overlapping thin film solar batteries according to claim 1, it is characterized in that, described crystallite PIN junction comprises microcrystal silicon PIN junction, microcrystalline silicon carbide PIN junction and crystallite SiGe PIN junction more.

3. solar cell according to claim 1 or 2, is characterized in that, described p-type amorphous layer is the amorphous layer of doped with boron element.

4. solar cell according to claim 1 or 2, is characterized in that, tell the amorphous layer that N-shaped amorphous layer refers to Doping Phosphorus element.

5. solar cell according to claim 1 or 2, is characterized in that, the thickness of described p-type amorphous layer and described N-shaped amorphous layer is 2nm ~ 30nm.

6. solar cell according to claim 1 or 2, is characterized in that, the energy gap of described p-type amorphous layer is 2 ~ 2.1eV, and refractive index is 3.55 ~ 3.65, and conductivity is greater than 2.00x10 ^?6s/cm.

7. solar cell according to claim 1 or 2, is characterized in that, the energy gap of described N-shaped amorphous layer is no more than 1.70eV, and refractive index is 4.60 ~ 4.80, and conductivity is greater than 6.00x10 ^?3s/cm.

8. solar cell according to claim 1 or 2, is characterized in that, according to the order of depositional coating, comprises following battery structure:

(1) substrate/TCO/p ?a ?Si _{1 ?x}ge _x/ i ?a ?Si _{1 ?x}ge _x/ n ?a ?Si _{1 ?x}ge _x/ central reflector layer/p ?a ?Si/i ?a ?Si/n ?a ?Si/ central reflector layer/p ?uc ?Si _{1 ?x}ge _x/ p-type amorphous layer/i ?uc ?Si _{1 ?x}ge _x/ N-shaped amorphous layer/n ?uc ?Si _{1 ?x}ge _x/ central reflector layer/p ?uc ?Si/p type amorphous layer/i ?uc ?Si/n type amorphous layer/n ?uc ?Si/ central reflector layer/p ?a ?SiC/i ?a ?SiC/n ?a ?SiC/ central reflector layer/p ?uc ?SiC/p type amorphous layer/i ?uc ?SiC/n type amorphous layer/n ?uc ?SiC/TCO/ antireflective coating;

(2) substrate/TCO/p ?a ?Si _{1 ?x}ge _x/ i ?a ?Si _{1 ?x}ge _x/ n ?a ?Si _{1 ?x}ge _x/ central reflector layer/p ?a ?Si/i ?a ?Si/n ?a ?Si/ central reflector layer/p ?uc ?Si _{1 ?x}ge _x/ p-type amorphous layer/i ?uc ?Si _{1 ?x}ge _x/ N-shaped amorphous layer/n ?uc ?Si _{1 ?x}ge _x/ central reflector layer/p ?uc ?Si/p type amorphous layer/i ?uc ?Si/n type amorphous layer/n ?uc ?Si/ central reflector layer/p ?uc ?SiC/i ?uc – SiC/p type amorphous layer/i ?uc ?SiC/n type amorphous layer/n ?uc ?SiC/TCO/ antireflective coating;

(3) substrate/TCO/p ?a ?Si _{1 ?x}ge _x/ i ?a ?Si _{1 ?x}ge _x/ n ?a ?Si _{1 ?x}ge _x/ central reflector layer/p ?a ?Si/i ?a ?Si/n ?a ?Si/ central reflector layer/p-type amorphous layer/i ?uc ?Si _{1 ?x}ge _x/ N-shaped amorphous layer/n ?uc ?Si _{1 ?x}ge _x/ central reflector layer/p ?uc ?Si/p type amorphous layer/i ?uc ?Si/n type amorphous layer/n ?uc ?Si/TCO/ antireflective coating;

(4) substrate/TCO/p ?a ?Si/i ?a ?Si/n ?a ?Si/ central reflector layer/p ?uc ?Si _{1 ?x}ge _x/ p-type amorphous layer/i ?uc ?Si _{1 ?x}ge _x/ N-shaped amorphous layer/n ?uc ?Si _{1 ?x}ge _x/ central reflector layer/p ?uc ?Si/p type amorphous layer/i ?uc ?Si/n type amorphous layer/n ?uc ?Si/TCO/ antireflective coating;

Wherein, the rete between tco layer and adjacent central reflector layer and between adjacent two central reflector layer is a knot, 0 < x < 1; "/" represent two-layer between interface; Substrate is glass, stainless steel or macromolecular material.