Heterojunction tandem solar cell and method of manufacturing the same
By designing multiple connecting layers and an overall barrier layer, the problem of unstable electrical connection after stacking heterojunction solar cells and perovskite solar cells was solved, which improved the conversion efficiency and lifespan of the cells, reduced production costs, and enhanced the stability of the cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU TALESUN SOLAR TECH CO LTD
- Filing Date
- 2023-08-09
- Publication Date
- 2026-06-12
AI Technical Summary
The existing heterojunction solar cells and perovskite solar cells, when stacked, suffer from unstable electrical connections in the bonding layers, resulting in high carrier consumption, short cell lifespan, and high cost, making it difficult for them to gain a mainstream position in the market.
A multi-layer interconnect structure is adopted, including a first interconnect sub-layer, a second interconnect sub-layer, and a third interconnect sub-layer. By adjusting the doping concentration and work function of the conductive oxide, combined with the silicon dioxide tunneling layer and the overall barrier layer, the stability of current transmission and prevention of ion and water vapor intrusion are ensured, and the work function of the interconnect layer is improved to adapt to the structure of the cells on both sides.
It improves the conversion efficiency and lifespan of tandem solar cells, reduces production costs, enhances anti-PID performance, and ensures the stability and high-efficiency power generation of the solar cells.
Smart Images
Figure CN116847672B_ABST
Abstract
Description
[Technical Field]
[0001] This application relates to a heterojunction tandem solar cell, belonging to the field of solar cell technology. [Background Technology]
[0002] Heterojunction solar cells are bifacial heterojunction structures that can receive light and generate electricity from both sides. They offer advantages such as low fabrication temperatures, high conversion efficiency, and good high-temperature performance, and are considered a mainstream technology for the future photovoltaic industry. However, due to the need to reduce production costs, heterojunction solar cells have not yet achieved mainstream dominance. Among other cell technologies, perovskite solar cells are also a key area of research, but their commercial application is currently limited by issues related to large-area fabrication and stability.
[0003] Although heterojunction solar cells and perovskite solar cells do not currently occupy a mainstream position in the market, continuously improving conversion efficiency has always been a research focus of the industry. With the current fabrication technology of heterojunction solar cells and perovskite solar cells, it is relatively easy to stack the two. Current research has found that the efficiency of solar cells stacked together can reach 35%, far exceeding that of single-type solar cells.
[0004] There are many technical problems to be solved in tandem solar cells. The main technical problems include how to easily realize the fabrication of perovskite solar cells on crystalline silicon cells. In this process, it is necessary to ensure that the two cells can be electrically connected in a good and stable manner. Therefore, the connection layer between the two tandem cells is a very critical structure. This connection layer needs to be able to stably transport charge carriers and can be well adapted to heterojunction cells and perovskite cells. [Summary of the Invention]
[0005] The purpose of this application is to provide a heterojunction tandem solar cell, which can effectively transmit the current in the tandem solar cell, and the connecting layer can also be stable in the tandem cell, thereby ensuring the life of the tandem cell. By optimizing the structure of the connecting layer in the tandem cell, the internal consumption in the tandem structure is reduced.
[0006] The purpose of this application is achieved through the following technical solution: This application provides a heterojunction tandem solar cell, including a heterojunction cell layer and a perovskite cell layer. The heterojunction cell layer sequentially includes a transparent conductive layer, an N-type amorphous silicon layer, an intrinsic amorphous silicon layer, an N-type monocrystalline substrate layer, an intrinsic amorphous silicon layer, and a P-type amorphous silicon layer. The perovskite cell layer sequentially includes a transparent conductive layer, an electron transport layer, a perovskite absorber layer, and a hole transport layer. A connecting layer is included between the heterojunction cell layer and the perovskite cell layer. The specific thickness of each layer in the heterojunction cell layer can be kept consistent with the structure of heterojunction solar cells in the current industry.
[0007] The connecting layer includes a first connecting sublayer, a second connecting sublayer, and a third connecting sublayer. The connecting layer in this application includes at least three layers, and other materials may be included between the connecting sublayers.
[0008] The first connecting layer is made of a doped conductive oxide, the second connecting layer is made of a metal silicide, and the third connecting layer is a doped conductive oxide layer. Conductive oxides are widely used in tandem solar cells. However, research has shown that when connecting layers are made of the same material, the work function of the connecting layer will affect the conductivity at the contact point. Moreover, the same material often has a mismatch with one of the structural layers at both ends. By changing the dopants in the conductive oxide, the work function of the conductive oxide can be adjusted, thereby adjusting the work function of the connecting layer.
[0009] The work functions of the first, second, and third connecting sublayers gradually increase; the work function of each connecting sublayer is adjusted by adjusting the dopant to avoid significant abrupt changes in the material structure and to prevent the concentration and aggregation of defects.
[0010] A silicon dioxide tunneling layer is included between the first and second connector layers; the tunneling oxide layer can prevent the migration of minority carrier holes and avoid minority carrier recombination.
[0011] An integral barrier layer is formed on the outer surface of the heterojunction tandem solar cell. The integral barrier layer covers the outer surface of the heterojunction tandem solar cell and is a layer formed by alternating inorganic material layers and organic material layers. Through the integral barrier layer, ions and water vapor are prevented from entering any layer of the tandem solar cell during application, thereby avoiding these factors from causing the performance degradation of the solar cell.
[0012] In one embodiment, the concentration of dopants in the first connecting sublayer gradually decreases from top to bottom.
[0013] In one embodiment, the concentration of dopants in the second connecting sublayer gradually increases from top to bottom.
[0014] In one embodiment, the thickness of the tunneling layer is 5-50 nm.
[0015] In one embodiment, the first and third connecting sublayers have the same thickness, and the thickness of the first connecting sublayer is 30%-45% of the thickness of the second connecting sublayer.
[0016] In one embodiment, the oxides of the first and third connecting layers are selected from one or more of the following oxides: zinc oxide, tin oxide, and indium oxide, and the dopants of the first and third connecting layers are selected from one or more of the following dopants: tungsten, vanadium, cobalt, and nickel.
[0017] This application also provides a method for manufacturing a heterojunction tandem solar cell, which is used to form the aforementioned tandem solar cell based on heterojunction and perovskite, comprising the following steps:
[0018] Step 1: Fabricate the heterojunction cell layer by forming an intrinsic amorphous silicon layer, an N-type amorphous silicon layer, an intrinsic amorphous silicon layer, and a P-type amorphous silicon layer on both sides of the N-type monocrystalline substrate.
[0019] Step 2: Form a connection layer on the heterojunction battery layer, forming a first connection sublayer, a second connection sublayer, and a third connection sublayer respectively;
[0020] Step 3: Form a perovskite solar cell layer on the connecting layer, and form a hole transport layer, a perovskite absorption layer, and an electron transport layer respectively;
[0021] Step 4: On the structure obtained in Step 3, a transparent conductive layer is formed on both sides;
[0022] Step 5: On the structure obtained in Step 4, an integral barrier layer is formed by alternating inorganic and organic material layers.
[0023] In one embodiment, the overall barrier layer is formed by forming an inorganic material layer by atomic layer deposition and an organic material layer by molecular layer deposition.
[0024] In one embodiment, the method of forming the connecting layer includes forming it using a chemical vapor deposition method, wherein the composition of the gas involved in the chemical vapor deposition is controlled during the formation of the first connecting sublayer and the third connecting sublayer, thereby controlling the composition of the first connecting sublayer and the third connecting sublayer.
[0025] In one embodiment, the step of forming a silicon dioxide tunneling layer is further included after forming the first connector sublayer.
[0026] Compared with the prior art, this application has the following beneficial effects: This application improves the connection layer structure in the tandem battery, regulates the work function of the connection layer, and adjusts it by changing the work function of the connection layer to adapt to the current output of the battery cells on both sides; a tunneling layer is set in the tandem battery to hinder the migration of minority carriers and avoid consumption inside the battery structure, further ensuring efficiency stability; furthermore, the process of forming the connection layer can also be used to form an overall barrier layer, which can prevent ion diffusion from the encapsulation material into the battery cell structure and improve anti-PID performance. [Attached Image Description]
[0027] Figure 1 This is a schematic diagram of the heterojunction tandem solar cell of this application.
[0028] Figure 2 This is a flowchart of the manufacturing method of the heterojunction tandem solar cell of this application. 【Detailed Implementation Methods】
[0029] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.
[0030] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.
[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0032] Please see Figure 1 , Figure 1This is a schematic diagram of the heterojunction tandem solar cell of this application. In a preferred embodiment of the heterojunction tandem solar cell of this application, the structure of the connecting layer between the cell layers is improved. By improving the connecting layer structure, the two cell layers are better connected in series, avoiding the additional consumption of charge carriers at the connecting layer. In the embodiments of this application, a heterojunction solar cell layer 1 and a perovskite solar cell layer 2 are included. The heterojunction solar cell layer 1 sequentially includes a first transparent conductive layer 11, an N-type amorphous silicon layer 12, a first intrinsic amorphous silicon layer 13, an N-type monocrystalline substrate layer 14, a second intrinsic amorphous silicon layer 15, and a P-type amorphous silicon layer 16. The perovskite solar cell layer 2 sequentially includes a second transparent conductive layer 21, an electron transport layer 22, a perovskite absorption layer 23, and a hole transport layer 24. A connecting layer 3 is included between the heterojunction solar cell layer 1 and the perovskite solar cell layer 2. The heterojunction solar cell layer 1 and the perovskite solar cell layer 2 can be made of any material that can be used as a solar cell layer structure. The heterojunction solar cell forms a PININ structure by forming an intrinsic amorphous silicon layer and a doped amorphous silicon layer on both sides of the substrate layer, and the specific material of the perovskite solar cell layer can be any material that can form the various structures of the perovskite solar cell layer. This application does not further limit the relevant materials.
[0033] The connection layer 3 includes a first connection sublayer, a second connection sublayer, and a third connection sublayer (not specifically shown in the attached figures). The definition of the above connection sublayers is not a strict spatial definition, but mainly reflects the three parts. It does not exclude the inclusion of other functional layers between each layer.
[0034] The first connecting layer is made of a doped conductive oxide, the second connecting layer is made of a metal silicide, and the third connecting layer is a doped conductive oxide layer. Metal silicides are common electrode materials in the semiconductor field, and their work function is closer to that of silicon-based semiconductors than that of metals. Each connecting layer needs to ensure light transmission; when using metal silicides, their thickness is controlled to reduce or even eliminate light absorption. The thickness of the metal silicide material can be controlled between 50-150 nm.
[0035] The work function of the first connecting sublayer, the second connecting sublayer, and the third connecting sublayer gradually increases. By adjusting the dopant, the work function is adjusted so that there are no obvious abrupt changes in the material composition and structure. While satisfying the work function change, the increase of defects in the material structure is avoided. This connection structure enables the tandem solar cell to better connect the two cell layers in series and minimizes the influence of the connecting layer on the charge carriers.
[0036] A silicon dioxide tunneling layer is included between the first and second connector layers; the tunneling oxide layer can prevent the migration of minority carrier holes and avoid minority carrier recombination.
[0037] An integral barrier layer is formed on the outer surface of a heterojunction tandem solar cell. This integral barrier layer covers the outer surface of the heterojunction tandem solar cell and is composed of alternating inorganic and organic material layers. This integral barrier layer prevents ions and moisture from entering any layer of the tandem solar cell during application, thereby avoiding performance degradation caused by these factors. In this application, the integral barrier layer is formed by stacking inorganic and organic material layers, specifically using molecular layer deposition (MLD) and atomic layer deposition (ALD) methods. This eliminates the influence of inconsistencies and differences in the surface morphology of the tandem solar cell. Furthermore, the alternating organic and inorganic barrier layers utilize the barrier effects of both organic and inorganic layers. The introduction of the organic layer alleviates the stress generated in the inorganic layer during thermal changes, preventing cracks in the inorganic layer and thus reducing its barrier effect.
[0038] Specifically, the concentration of dopants in the first connecting sublayer gradually decreases from top to bottom.
[0039] Specifically, the concentration of dopants in the second connecting sublayer gradually increases from top to bottom.
[0040] Specifically, the thickness of the tunneling layer is 5-50 nm, and the thickness of the tunneling layer is further limited to 5-20 nm, more preferably 5-10 nm.
[0041] Specifically, the first and third connecting sublayers have the same thickness, and the thickness of the first connecting sublayer is 30%-45% of the thickness of the second connecting sublayer.
[0042] Specifically, the oxides of the first connecting sublayer and the third connecting sublayer are selected from one or more of the following oxides: zinc oxide, tin oxide, and indium oxide, and the dopants of the first connecting sublayer and the third connecting sublayer are selected from one or more of the following dopants: tungsten, vanadium, cobalt, and nickel. Specific Implementation Example 1:
[0044] The first connecting sublayer between the heterojunction solar cell layer structure and the perovskite solar cell layer structure is tungsten-doped tin oxide, and the second connecting sublayer is cobalt-doped indium oxide, with the doping concentration remaining unchanged. Specific Implementation Example 2:
[0046] The first connecting sublayer between the heterojunction solar cell layer structure and the perovskite solar cell layer structure is tungsten-doped tin oxide, and the second connecting sublayer is cobalt-doped indium oxide. The doping concentration varies, causing its work function to change gradually.
[0047] Comparative example:
[0048] The connecting layer between the heterojunction solar cell layer structure and the perovskite solar cell layer structure is made of metal silicide.
[0049] The heterojunction battery layer structure, perovskite battery layer structure, and the material of the second connecting sublayer are consistent in the specific embodiments and comparative examples.
[0050] The experimental results showed that the efficiency of the tandem solar cell in Specific Embodiment 2 was 0.3% higher than that in Specific Embodiment 1, while the efficiency of the comparative example was 0.5% lower than that of the tandem solar cell in Specific Embodiment 1. This demonstrates that the tandem solar cell used in this application has a superior conversion efficiency.
[0051] Please see Figure 1 This application provides a flowchart of a method for manufacturing a heterojunction tandem solar cell, comprising the following steps:
[0052] Step 1: Fabricate heterojunction cell layer 1. Form a first intrinsic amorphous silicon layer 13, an N-type amorphous silicon layer 12, a second intrinsic amorphous silicon layer 15, and a P-type amorphous silicon layer 16 on both sides of the N-type monocrystalline substrate layer 14, respectively. The heterojunction cell layer 1 and the perovskite cell layer 2 can be made of any material that can be used as the cell layer structure. The heterojunction solar cell forms a PININ structure by forming an intrinsic amorphous silicon layer and a doped amorphous silicon layer on both sides of the substrate layer, and the specific material of the perovskite cell layer can be any material that can form the various structures of the perovskite cell layer.
[0053] Step 2: Form a connection layer 3 on the heterojunction battery layer 1, forming a first connection sublayer, a second connection sublayer, and a third connection sublayer respectively;
[0054] Step 3: Form a perovskite solar cell layer 2 on the connecting layer 3, and form a hole transport layer 24, a perovskite absorption layer 23, and an electron transport layer 22 respectively;
[0055] Step 4: On the structure obtained in Step 3, a transparent conductive layer 11 is formed on both sides;
[0056] Step 5: On the structure obtained in Step 4, an integral barrier layer is formed by alternating inorganic and organic material layers.
[0057] The first connecting layer is made of a conductive oxide with dopants, the second connecting layer is made of a metal silicide, and the third connecting layer is a conductive oxide layer with dopants. The thickness of the metal silicide material can be controlled between 50-150 nm, and the thickness of the first and third connecting layers can be controlled to be 1.2-2.5 times the thickness of the second connecting layer.
[0058] Specifically, the overall barrier layer is formed by forming an inorganic material layer using atomic layer deposition (ALD) and an organic material layer using molecular layer deposition (MLD). This overall barrier layer prevents ions and moisture from entering any layer of the tandem solar cell during application, thus avoiding performance degradation caused by these factors. The overall barrier layer is formed by stacking inorganic and organic material layers, specifically using molecular layer deposition and atomic layer deposition methods, which eliminates the influence of inconsistencies and differences in surface morphology of the tandem solar cell.
[0059] Specifically, the method for forming the connecting layer 3 includes using chemical vapor deposition (CVD). During the formation of the first and third connecting sublayers, the composition of the gas involved in the CVD is controlled to regulate the composition of the first and third connecting sublayers. By adjusting the gas composition of the CVD, the composition of the material layers is adjusted in situ to achieve the desired work function and its variation as needed.
[0060] Specifically, after forming the first connector layer, the process further includes forming a silicon dioxide tunneling layer. The thickness of the tunneling layer is 5-50 nm, and is further limited to 5-20 nm, more preferably 5-10 nm.
[0061] The heterojunction tandem solar cell and its fabrication method disclosed in this application include a heterojunction cell layer and a perovskite cell layer, with a connecting layer between the heterojunction cell layer and the perovskite cell layer. The work function of each connecting sublayer gradually increases, which improves the connecting layer structure in the tandem cell. By adjusting the work function of the connecting layer, it can be adapted to the current extraction of the cell structures on both sides. The process of forming the connecting layer can also be used to form an overall barrier layer. The overall barrier layer can prevent ion diffusion from the encapsulation material into the cell structure and improve the anti-PID performance.
[0062] The heterojunction tandem solar cell of this application includes a heterojunction cell layer and a perovskite cell layer. By improving the connecting layer, the formed tandem solar cell can more effectively utilize the solar spectrum and obtain higher open-circuit voltage and short-circuit current, thus significantly improving the conversion efficiency of the tandem cell.
[0063] The above is only one specific implementation of this application, and any other improvements made based on the concept of this application shall be considered within the scope of protection of this application.
Claims
1. A heterojunction tandem solar cell, comprising a heterojunction cell layer and a perovskite cell layer, wherein the heterojunction cell layer sequentially comprises a transparent conductive layer, an N-type amorphous silicon layer, an intrinsic amorphous silicon layer, an N-type monocrystalline substrate layer, an intrinsic amorphous silicon layer, and a P-type amorphous silicon layer, and the perovskite cell layer sequentially comprises a transparent conductive layer, an electron transport layer, a perovskite absorber layer, and a hole transport layer, and a connecting layer is included between the heterojunction cell layer and the perovskite cell layer, characterized in that... The connection layer includes a first connection sublayer, a second connection sublayer, and a third connection sublayer; The first connecting sublayer is made of a doped conductive oxide, the second connecting sublayer is made of a metal silicide, and the third connecting sublayer is a doped conductive oxide layer. The work functions of the first connection sublayer, the second connection sublayer, and the third connection sublayer gradually increase; A silica tunneling layer is included between the first connector layer and the second connector layer; An integral barrier layer is formed on the outer surface of the heterojunction tandem solar cell. The integral barrier layer covers the outer surface of the heterojunction tandem solar cell and is a layer formed by alternating inorganic material layers and organic material layers. The thickness of the tunneling layer is 5-50 nm; The first and third connecting sublayers have the same thickness, and the thickness of the first connecting sublayer is 30%-45% of the thickness of the second connecting sublayer.
2. The heterojunction tandem solar cell as described in claim 1, characterized in that, The concentration of dopants in the first connecting sublayer gradually decreases from top to bottom.
3. The heterojunction tandem solar cell as described in claim 2, characterized in that, The concentration of dopants in the second connecting sublayer gradually increases from top to bottom.
4. The heterojunction tandem solar cell as described in claim 1, characterized in that, The oxides of the first and third connecting layers are selected from one or more of the following oxides: zinc oxide, tin oxide, and indium oxide. The dopants of the first and third connecting layers are selected from one or more of the following dopants: tungsten, vanadium, cobalt, and nickel.
5. A method for manufacturing a heterojunction tandem solar cell according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Fabricate the heterojunction cell layer by forming an intrinsic amorphous silicon layer, an N-type amorphous silicon layer, an intrinsic amorphous silicon layer, and a P-type amorphous silicon layer on both sides of the N-type monocrystalline substrate. Step 2: Form a connection layer on the heterojunction battery layer, forming a first connection sublayer, a second connection sublayer, and a third connection sublayer respectively; Step 3: Form a perovskite solar cell layer on the connecting layer, and form a hole transport layer, a perovskite absorption layer, and an electron transport layer respectively; Step 4: On the structure obtained in Step 3, a transparent conductive layer is formed on both sides; Step 5: On the structure obtained in Step 4, an integral barrier layer is formed by alternating inorganic and organic material layers.
6. The method for manufacturing a heterojunction tandem solar cell as described in claim 5, characterized in that, The overall barrier layer is formed by forming an inorganic material layer by atomic layer deposition and an organic material layer by molecular layer deposition.
7. The method for manufacturing a heterojunction tandem solar cell as described in claim 5, characterized in that, The method for forming the connecting layer includes using chemical vapor deposition, wherein the composition of the gas involved in the chemical vapor deposition is controlled during the formation of the first and third connecting sublayers, thereby controlling the composition of the first and third connecting sublayers.
8. The method for manufacturing a heterojunction tandem solar cell as described in claim 7, characterized in that, The process includes forming a silicon dioxide tunneling layer after the formation of the first connector layer.