201128781 六、發明說明： 【發明所屬之技術領域】 [0001] 本發明係有關於一種具有多層結構的薄膜太陽能電池， 特別是有關於一種在光吸收層中具有複數個光電轉換層 的多層結構薄膜太陽能電池。 【先前技秫ί】 [0002] 20世紀70年代，由美國貝爾實驗室首先研製出的矽太陽 能電池逐步發展起來。隨著太陽電池之發展，如今太陽 能電池有多種類型，典型的有單晶矽太陽能電池、多晶 Θ . 梦太陽能電池、非晶^夕太陽能電、池、化合物太陽能電池 、染料敏化太陽能電池等。太陽能電池主要是利用光伏 效應（photovoltaic ef fect)，將光能吸收後直接轉換 成電能的一種P/N接面（p-n junction)的半導體結構。 近年來，為因應太陽能電池薄型化的要求，多層薄膜太 陽能電池成為現今之發展趨勢。多層薄膜太陽電池最大 優點就是生產成本較低，然其效率和穩定度的問題也尚 待改善。 [0003] 請參考第1圖，為一種習知之多層薄膜太陽能電池之剖 視圖，而此習知之多層薄膜太陽能電池10至少包含依序 堆疊形成的基板11、前電極層12、光吸收層13與背電極 層14，其中此光吸收層13之組成進一步包含依序堆疊 形成的非晶石夕（amorphous crystal si 1 icon，a-si) 層 131 與微晶石夕（micro-crystal silicon，u-si)層 13 2。然，在此習知之光吸收層13之材質中，由於非晶 矽層131所經之電流量，為較大安培之電流量，而微晶矽 099104288 表單編號A0101 第3頁/共13頁 0992008033-0 201128781 層1 3 2所經之電流量，為較小安培之電流量，因此非晶矽 層131與微晶矽層132兩者之間的電流量會互受侷限，造 成電流量會趨近於小安培之電流量，如第1圖電流C1所示 ，因此造成電流不匹配（Current Matching Issue)之 問題，導致此習知之多層薄膜太陽能電池之光電轉換 效率降低。 【發明内容】 [0004] 為了解決上述先前技術不盡理想之處，本發明提供了一 種具有多層結構的薄膜太陽能電池，至少包含依序堆疊 形成的基板、前電極層、具有複數個光電轉換層的光吸 收層與背電極層。此光吸收層，進一步包含依序堆疊形 成的第一光電轉換層、第一透明導電層、絕緣層、第二 透明導電層以及第二光電轉換層。藉此，在上述之具有 多層結構的薄膜太陽能電池中可成為至少兩個獨立之電 流通路，各自導通電流。 [0005] 因此，本發明之主要目的係提供一種具有多層結構的薄 膜太陽能電池，藉由其中之具有多層結構的薄膜太陽能 電池内可成為至少兩個獨立之電流通路，各自導通電流 ，故可以減少電流不匹配之問題。 [0006] 本發明之次要目的係提供一種具有多層結構的薄膜太陽 能電池，藉由其中之具有多層結構的薄膜太陽能電池内 可成為至少兩個獨立之電流通路，各自導通電流，藉以 提升光電轉換效率。 【實施方式】 [0007] 由於本發明係揭露一種具有多層結構的薄膜太陽能電池 099104288 表單編號A0101 第4頁/共13頁 0992008033-0 201128781 ，、中/t彻之太陽能電池之光電轉換原理及製作原理 為相關技術領域具有通常知識切㈣瞭，故以下 文中之說明，不再作完整描述。同時，以下文中所對照 之圖式’係表達與本發明特徵有關之結構Μ，並未亦 不需要依據實際尺寸完整繪製，特先敘明。 [0008] Ο 妓請參考第2圖，係本發明提出之第—較佳實施例，為 種具有夕層結構的薄膜太陽能電池20，至少包含依序 隹疊形成的基板21、前電極層22、具有複數個光電轉換 層的光吸收層23與背電極層24。此光吸收層23進一步包 含依序堆疊形成的第一光電轉換層231、第一透明導電層 232、絕緣層233、第二透明導電層234以及第二光電轉 換層235。上述之第一光電株換層231的材料較佳為非晶 矽、絕緣層233的材料可為矽氧化物或矽氮化物、第二 光電轉換層235的材料較佳為微晶矽。201128781 VI. Description of the Invention: [Technical Field] [0001] The present invention relates to a thin film solar cell having a multilayer structure, and more particularly to a multilayer structure film having a plurality of photoelectric conversion layers in a light absorbing layer Solar battery. [Previous Techniques] [0002] In the 1970s, the solar cells that were first developed by Bell Labs in the United States gradually developed. With the development of solar cells, there are many types of solar cells today, typically single crystal germanium solar cells, polycrystalline germanium. Dream solar cells, amorphous solar cells, cells, compound solar cells, dye-sensitized solar cells, etc. . A solar cell is mainly a P/N junction semiconductor structure that utilizes a photovoltaic effect to directly convert light energy into electrical energy. In recent years, multi-layer thin-film solar cells have become the trend of development in response to the demand for thinning of solar cells. The biggest advantage of multilayer thin-film solar cells is the low cost of production, but the problems of efficiency and stability have yet to be improved. 1 is a cross-sectional view of a conventional multilayer thin film solar cell, and the conventional multilayer thin film solar cell 10 includes at least a substrate 11 formed in a sequential stack, a front electrode layer 12, a light absorbing layer 13 and a back The electrode layer 14 , wherein the composition of the light absorbing layer 13 further comprises an amorphous crystal si 1 icon (a-si) layer 131 and micro-crystal silicon (u-si) formed in sequence. ) Layer 13 2 . However, in the material of the conventional light absorbing layer 13, the amount of current passing through the amorphous germanium layer 131 is the amount of current of a large amperage, and the microcrystal 矽 099104288 Form No. A0101 Page 3 / Total 13 Page 0992008033 -0 201128781 The amount of current passed by layer 1 3 2 is the amount of current of a small amperage. Therefore, the amount of current between the amorphous germanium layer 131 and the microcrystalline germanium layer 132 is mutually limited, resulting in a current amount. The amount of current close to the small amperage, as shown by the current C1 in Fig. 1, causes a problem of current mismatch (Current Matching Issue), resulting in a decrease in the photoelectric conversion efficiency of the conventional multilayer thin film solar cell. SUMMARY OF THE INVENTION [0004] In order to solve the above-mentioned prior art, the present invention provides a thin film solar cell having a multilayer structure, comprising at least a substrate formed by sequentially stacking, a front electrode layer, and a plurality of photoelectric conversion layers. Light absorbing layer and back electrode layer. The light absorbing layer further includes a first photoelectric conversion layer, a first transparent conductive layer, an insulating layer, a second transparent conductive layer, and a second photoelectric conversion layer which are sequentially stacked. Thereby, in the above-described thin film solar cell having a multilayer structure, at least two independent current paths can be formed, and currents are respectively conducted. [0005] Therefore, the main object of the present invention is to provide a thin film solar cell having a multilayer structure, in which a thin film solar cell having a multilayer structure can be used as at least two independent current paths, each of which conducts a current, thereby reducing The problem of current mismatch. [0006] A secondary object of the present invention is to provide a thin film solar cell having a multilayer structure, in which a thin film solar cell having a multilayer structure can be used as at least two independent current paths, each of which conducts a current, thereby improving photoelectric conversion. effectiveness. [Embodiment] [0007] Since the present invention discloses a thin film solar cell having a multi-layer structure 099104288 Form No. A0101 Page 4 / 13 pages 0992008033-0 201128781, the photoelectric conversion principle and fabrication of the solar cell of the medium/t The principle is that the related art has the usual knowledge (4), and therefore, the description below will not be completely described. At the same time, the drawings referred to in the following texts represent structural structures related to the features of the present invention, and are not required to be completely drawn according to actual dimensions, as described in detail. [0008] Referring to FIG. 2, a first preferred embodiment of the present invention is a thin film solar cell 20 having a layer structure comprising at least a substrate 21 and a front electrode layer 22 which are sequentially stacked. The light absorbing layer 23 and the back electrode layer 24 having a plurality of photoelectric conversion layers. The light absorbing layer 23 further includes a first photoelectric conversion layer 231, a first transparent conductive layer 232, an insulating layer 233, a second transparent conductive layer 234, and a second photoelectric conversion layer 235 which are sequentially stacked. The material of the first photovoltaic layer change layer 231 is preferably amorphous, the material of the insulating layer 233 may be tantalum oxide or tantalum nitride, and the material of the second photoelectric conversion layer 235 is preferably microcrystalline germanium.
[0009] G 請繼續參考第2圖，在光線L射入此具有多層結構的薄膜 太陽能電池20之後，在第一光電轉換層231與第二光電 ：；：：: - .............- 轉換層235之中备自產生光電，轉換效應，產生電流C2與C3 。而藉由絕緣層233的阻隔，前電極層22、第一光電轉換 層231及第一透明導電層232形成為一個獨立之第一電流 通路25，使得電流C2僅於第一電流通路25中流動。同樣 地，第二透明導電層234、第二光電轉換層235以及背電 極層24則形成為另一個獨立之第二電流通路26 ’使得電 流C3僅於第二電流通路26中流動。 又，流經第一電流通路25的電流C2通常具有較大之安培 數，而流經第二電流通路26的電流c3則通常具有較小之 099104288 表單編號A0101 第5頁/共13頁 0992008033-0 [0010] 201128781 安培數，並且，上述電流C2與C3不會互受干擾及侷限， 故本發明可以減少習知多層薄膜太陽能電池的電流匹 配問題。 [0011] 重要的是，在此具有多層結構的薄膜太陽能電池20 中，為了要形成至少兩個各自獨立的第一電流通路25與 第二電流通路26，本發明是在第一光電轉換層231與第二 光電轉換層235之中設置有第一透明導電層232、絕緣層 233以及第二透明導電層234。但是為了保持其光電轉換 效率，不使其加入其他多層結構而降低其光電轉換效率 $ ，亦即為了可以讓第一光電轉換層231與第二光電轉換層 235都充分地吸收到光線L，光吸收層23中之絕緣層233 以具有75%以上的穿透率為佳，而第一透明導電層231及 第二透明導電層235則以具有80%以上的穿透率為佳。 [0012] 請再參考第1圖，倘若以先前技術結構的多層薄膜太陽能 10,即光吸收層13中僅由依序堆疊的非晶矽層131與 微晶矽層132所形成，經過本發明之實驗測試，此種多層 薄膜太陽能電池10的光電轉換效率約為11%。而依據本發 I. 明所提供的具有多層結構的薄膜太陽能電池20，當其 中絕緣層233、第一透明導電層231及第二透明導電層 235的穿透率在95%以上時，測試結果顯示，本發明所提 供之具有多層結構的薄膜太陽能電池20所具有的光電 轉換效率，約為先前技術所提供的多層薄膜太陽能電池 10光電轉換效率（11%)之1. 1416倍。也就是說，利用 本發明提供的具有多層結構的薄膜太陽能電池2所產生 的光電轉換效率，會比先前技術所提供之多層太陽能電 099104288 表單編號A0101 第6頁/共13頁 0992008033-0 201128781 池1〇所產生的光電轉換效率再增進1416%。因此，本發 月了以改善先削技術的缺點，可以'進而提升發電效率。 [0013] 上述之基板21、前電極層22、第一透明導電層232及第二 透明導電層234均選用的材質為透光的材質’基板21係為 玻璃基板，前電極層22、第—透明導電層232及第二透明 導電層234可為單層結構或多層結構之透明導電氧化物 (TCO. Transparent Conductive Oxide)，而其可選 ❹ 用材料為二氧化錫（Sn〇2)、氧化銦錫（IT0)、氧化鋅 (ZnO)、氧化铭辞（AZ〇)、氧化鎵錫（GZ〇)或氧化銦辞 (ιζο)等所構成的材料；光吸收層23為多層結構所組成， 而其可選用材料為非晶矽 '微晶矽、矽氡化物或矽氮化 物所構成的材料；背電極層24可為單結構或多層結構所 組成’其包含一金屬層，其金屬層可選用材料為銀（Ag) 、鋁（A1)、鉻（Cr)、鈦（Ti)、鎳（Ni)或irUu)等金屬 ，此外背電極層24進一步包含一透明導電氧化物，其可 選用材料為二氧化錫（Sn09)、氧化銦錫（IT0)、氧化鋅 L. Ο [0014] (ZnO) '氧化鋁鋅（AZ0)、氧化鎵鋅（GZ0)或氧化銦鋅 (IZ0)等所構成的材料。 請參考第3圖，係本發明提出之第二較佳實施例，為另一 種具有多層結構的薄膜太陽能電池30,至少包含依序堆 疊形成的基板31、前電極層32、具有複數個光電轉換層 的光吸收層33與背電極層34。此光吸收層33進一步包含 依序堆疊形成的非晶矽光電轉換層331、第一透明導電層 332、絕緣層333、第二透明導電層334以及微晶矽光電 轉換層335。此具有多層結構的薄膜太陽能電池30之其 099104288 表單編號A0101 第7頁/共13頁 0992008033-0 201128781 他特徵如前述之第一較佳實施例所揭露者。 [0015] 以上所述僅為本發明之較佳實施例，並非用以限定本發 明之申請專利權利；同時以上的描述，對於熟知本技術 領域之專門人士應可明瞭及實施，因此其他未脫離本發 明所揭示之精神下所完成的等效改變或修飾，均應包含 在申請專利範圍中。 【圖式簡單說明】 [0016] 第1圖為一先前技術所提供之多層薄膜太陽能電池。 [0017] 第2圖為一刮視圖，係根據本發明提供之第一較佳實施例 ，為一種多層薄膜太陽能電.池。.[0009] Please continue to refer to FIG. 2, after the light L is incident on the thin film solar cell 20 having the multilayer structure, in the first photoelectric conversion layer 231 and the second photoelectric:::::-... .......- The conversion layer 235 is prepared to generate photoelectricity, conversion effects, and generate currents C2 and C3. The first electrode layer 22, the first photoelectric conversion layer 231 and the first transparent conductive layer 232 are formed as a separate first current path 25 by the barrier of the insulating layer 233, so that the current C2 flows only in the first current path 25. . Similarly, the second transparent conductive layer 234, the second photoelectric conversion layer 235, and the back electrode layer 24 are formed as another independent second current path 26' such that the current C3 flows only in the second current path 26. Moreover, the current C2 flowing through the first current path 25 usually has a larger amperage, and the current c3 flowing through the second current path 26 is usually smaller. 099104288 Form No. A0101 Page 5 / Total 13 Page 0992008033- [0010] 201128781 Amperage, and the above currents C2 and C3 do not interfere with each other and are limited, so the present invention can reduce the current matching problem of the conventional multilayer thin film solar cell. [0011] What is important is that in the thin film solar cell 20 having a multilayer structure, in order to form at least two independent first current paths 25 and second current paths 26, the present invention is in the first photoelectric conversion layer 231. A first transparent conductive layer 232, an insulating layer 233, and a second transparent conductive layer 234 are disposed in the second photoelectric conversion layer 235. However, in order to maintain its photoelectric conversion efficiency, it is not added to other multilayer structures to reduce its photoelectric conversion efficiency, that is, in order to allow the first photoelectric conversion layer 231 and the second photoelectric conversion layer 235 to sufficiently absorb light L, light The insulating layer 233 in the absorbing layer 23 preferably has a transmittance of 75% or more, and the first transparent conductive layer 231 and the second transparent conductive layer 235 have a transmittance of 80% or more. [0012] Please refer to FIG. 1 again, if the multilayer thin film solar energy 10 of the prior art structure, that is, the amorphous germanium layer 131 and the microcrystalline germanium layer 132 which are sequentially stacked in the light absorbing layer 13, are formed by the present invention. Experimentally, the photoelectric conversion efficiency of such a multilayer thin film solar cell 10 was about 11%. According to the thin film solar cell 20 having a multi-layer structure provided by the present invention, when the transmittance of the insulating layer 233, the first transparent conductive layer 231, and the second transparent conductive layer 235 is 95% or more, the test result is obtained. The photo-electric conversion efficiency (11%) of the multilayer thin-film solar cell 10 provided by the prior art is 1. 1416 times, which is provided by the present invention. That is to say, the photoelectric conversion efficiency produced by the thin film solar cell 2 having the multilayer structure provided by the present invention is higher than that of the prior art provided by the multi-layer solar power 099104288 Form No. A0101 Page 6 / Total 13 Page 0992008033-0 201128781 The photoelectric conversion efficiency produced by 1〇 is further increased by 1416%. Therefore, this month to improve the shortcomings of the cutting technology, can further improve power generation efficiency. [0013] The substrate 21, the front electrode layer 22, the first transparent conductive layer 232, and the second transparent conductive layer 234 are all made of a transparent material. The substrate 21 is a glass substrate, and the front electrode layer 22 is first. The transparent conductive layer 232 and the second transparent conductive layer 234 may be a single layer structure or a multilayer structure of transparent conductive oxide (TCO. Transparent Conductive Oxide), and the optional material is tin dioxide (Sn〇2), oxidation. a material composed of indium tin (IT0), zinc oxide (ZnO), oxidized inscription (AZ〇), gallium oxide tin (GZ〇) or indium oxide (ιζο); the light absorbing layer 23 is composed of a multilayer structure. The optional material is a material composed of amorphous 微 'microcrystalline germanium, germanide or germanium nitride; the back electrode layer 24 may be composed of a single structure or a multilayer structure, which comprises a metal layer, and the metal layer thereof may be The material selected is a metal such as silver (Ag), aluminum (A1), chromium (Cr), titanium (Ti), nickel (Ni) or irUu), and the back electrode layer 24 further comprises a transparent conductive oxide, and an optional material thereof Tin dioxide (Sn09), indium tin oxide (IT0), zinc oxide L. Ο [0014] (Zn O) A material composed of alumina zinc (AZ0), gallium zinc oxide (GZ0) or indium zinc oxide (IZ0). Please refer to FIG. 3 , which is a second preferred embodiment of the present invention. The thin film solar cell 30 having a multilayer structure includes at least a substrate 31 and a front electrode layer 32 which are sequentially stacked, and have a plurality of photoelectric conversions. The light absorbing layer 33 of the layer and the back electrode layer 34. The light absorbing layer 33 further includes an amorphous germanium photoelectric conversion layer 331, a first transparent conductive layer 332, an insulating layer 333, a second transparent conductive layer 334, and a microcrystalline germanium photoelectric conversion layer 335 which are sequentially stacked. The thin film solar cell 30 having the multilayer structure is 099104288 Form No. A0101 Page 7 of 13 0992008033-0 201128781 The features are as disclosed in the first preferred embodiment described above. The above description is only a preferred embodiment of the present invention, and is not intended to limit the patent application rights of the present invention. The above description should be understood and implemented by those skilled in the art, so that the others are not separated. Equivalent changes or modifications made in the spirit of the present invention should be included in the scope of the patent application. BRIEF DESCRIPTION OF THE DRAWINGS [0016] Fig. 1 is a multilayer thin film solar cell provided by a prior art. 2 is a plan view showing a multilayer thin film solar cell according to a first preferred embodiment of the present invention. .
[0018] 第3圖為一剖視圖，係根據本發明提供之第二較佳實施例 ，為另一種多層薄膜太陽能電池。 【主要元件符號說明】 [0019] 多層薄膜太陽能電池（先前技術）1 0 [0020] 前電極層（先前技術） 11 [0021] 光吸收層（先前技術） 13 [0022] 非晶矽層（先前技術） 131 [0023] 微晶矽層（先前技術） 132 [0024] 背電極層（先前技術） 14 [0025] 電流（先前技術）C1 [0026] 多層結構的薄膜太陽能電池20、30 [0027] 基板21、31 表單編號A0101 第8頁/共13頁 099104288 0992008033-0 201128781 [0028] [0029] [0030] [0031] [0032] [0033] [0034]3 is a cross-sectional view showing another multilayer thin film solar cell according to a second preferred embodiment of the present invention. [Main Element Symbol Description] [0019] Multilayer Thin Film Solar Cell (Prior Art) 10 [0020] Front Electrode Layer (Prior Art) 11 [0021] Light Absorbing Layer (Prior Art) 13 [0022] Amorphous germanium layer (previously Technology] 131 [0023] Microcrystalline germanium layer (prior art) 132 [0024] Back electrode layer (prior art) 14 [0025] Current (Prior Art) C1 [0026] Multilayer structured thin film solar cells 20, 30 [0027] Substrate 21, 31 Form No. A0101 Page 8 / Total 13 Pages 099104288 0992008033-0 201128781 [0028] [0030] [0033] [0033]
[0035] . [0036] [0037] [0038] [0039] Γ r\r\ j λ Ί LUU4UJ ❹ [0041] 前電極層22、32 光吸收層23、33 第一光電轉換層231 第一透明導電層232、332 絕緣層233、333 第二透明導電層234、334 第二光電轉換層235 背電極層24、34 第一電流通路25 第·-電流通路2 6 電流C 2、C 3 非晶矽光電轉換層331 J.Ut O .1- ▲士 \ U C? Ο Γ» Γ- ®品·电得換層 CM 0[0039] [0039] [0039] Γ r\r\ j λ Ί LUU4UJ ❹ [0041] front electrode layer 22, 32 light absorbing layer 23, 33 first photoelectric conversion layer 231 first transparent Conductive layer 232, 332 Insulating layer 233, 333 Second transparent conductive layer 234, 334 Second photoelectric conversion layer 235 Back electrode layer 24, 34 First current path 25 Current current path 2 6 Current C 2, C 3 Amorphous矽 photoelectric conversion layer 331 J.Ut O .1- ▲士\ UC? Ο Γ» Γ-® product·electricity change layer CM 0
光線L 099104288 表單編號A0101 第9頁/共13頁 0992008033-0Light L 099104288 Form No. A0101 Page 9 of 13 0992008033-0