阅读说明：本技术 一种高效稳定的钙钛矿/硅两端叠层太阳电池 (Efficient and stable perovskite/silicon two-end laminated solar cell ) 是由 张晓丹 陈兵兵 李兴亮 李玉成 王鹏阳 黄茜 许盛之 侯国付 魏长春 陈新亮 任 于 2020-04-01 设计创作，主要内容包括：本发明开发了一种高效稳定的钙钛矿/硅两端叠层太阳电池,该叠层电池以窄带隙钙钛矿电池为顶电池,通过中间连接层与底部晶硅电池构成两端的叠层结构电池,确保叠层电池获得高开压的前提下解决顶、底电池的电流匹配问题。即利用适当窄带隙钙钛矿电池开压损失小的特点,使顶部电池获得更大的电流,同时通过适当增加底部晶硅电池的受光面积来补偿底电池的电流损失,从而实现顶、底电池的电流匹配,在获得高效叠层电池效率的同时保障电池的稳定性。(The invention develops an efficient and stable perovskite/silicon two-end laminated solar cell, the laminated solar cell takes a narrow-band-gap perovskite cell as a top cell, and a laminated structure cell at two ends is formed by a middle connecting layer and a bottom crystalline silicon cell, so that the current matching problem of the top cell and the bottom cell is solved on the premise of ensuring that the laminated cell obtains high open voltage. The characteristics that the voltage-opening loss of a proper narrow-band-gap perovskite battery is small are utilized, so that the top battery obtains larger current, and meanwhile, the current loss of the bottom battery is compensated by properly increasing the light receiving area of the bottom crystalline silicon battery, so that the current matching of the top battery and the bottom battery is realized, and the stability of the battery is ensured while the efficiency of the high-efficiency laminated battery is obtained.)

1. A high-efficiency stable perovskite/silicon two-end laminated solar cell is characterized in that a perovskite cell with a narrow band gap of 1.40-1.65eV is used as a top cell, and a laminated structure at two ends is formed by a middle connecting layer and a bottom crystalline silicon cell; the areas of the top battery and the bottom battery in the laminated batteries at the two ends are not equal, the area ratio of the top battery to the bottom battery is 0.5-1.0, the current of the bottom battery is compensated by properly increasing the area of the bottom crystalline silicon battery, and the current matching of the top battery and the bottom battery is realized.

2. An efficient and stable perovskite/silicon two-terminal stacked solar cell as claimed in claim 1, wherein the perovskite top cell is a narrow band gap organic-inorganic hybrid perovskite material or an all-inorganic perovskite material; the components of the material are lead-based, tin-based or lead-tin mixed perovskite material.

3. A highly efficient stable perovskite/silicon two-terminal stacked solar cell as claimed in claim 1, wherein the perovskite top cell is prepared by a solution method of two-step sequential deposition or one-step anti-solvent deposition, or by evaporation deposition or chemical vapor deposition; the structure of the perovskite top battery and the structure of the bottom crystalline silicon battery select a pin battery structure or a nip battery structure.

4. An efficient and stable perovskite/silicon two-terminal laminated solar cell as claimed in claim 1, wherein the cavity material of the perovskite cell is inorganic NiO_XMnS or CuSCN, or is an organic material PTAA, Spiro-OMeTAD or Spiro-TTB; the electron layer transmission material is inorganic SnO₂Or TiO₂Etc. or organic material PCBM or C₆₀。

5. A highly efficient stable perovskite/silicon two-end laminated solar cell as claimed in claim 1, wherein the transparent electrode material on the upper surface of the perovskite top cell is ITO, IZO, IO: H or IZO.

6. An efficient and stable perovskite/silicon two-end laminated solar cell as claimed in claim 1, wherein the anti-reflection material on the transparent electrode material on the upper surface of the perovskite top cell is MgF₂LiF or SiO₂。

7. A highly efficient stable perovskite/silicon two-terminal stacked solar cell as claimed in claim 1, wherein the intermediate connection layer is a transparent conductive thin film ITO or IZO, or is an amorphous silicon, microcrystalline silicon, nanocrystalline silicon or silicon oxygen material, or is selected from a transparent conductive adhesive to realize the connection of the top perovskite and the bottom crystalline silicon cell.

8. An efficient and stable perovskite/silicon two-end laminated solar cell as claimed in claim 1, wherein the crystalline silicon bottom cell is a planar silicon cell, a single-sided textured or double-sided textured silicon solar cell.

9. A highly efficient stable perovskite/silicon two-terminal stacked solar cell as claimed in claim 9, wherein said silicon cell is one of the following: n-type silicon chip, p-type silicon chip, CZ type or FZ type; the silicon cell is one of the following: a silicon heterojunction cell, TOP-Con cell, POLO cell, DASH cell, or homojunction cell; the homojunction battery is specifically a PERC, PERL or PERT battery.

10. An efficient and stable perovskite/silicon two-terminal-stacked solar cell as claimed in claim 1, wherein the structure of the perovskite cell is planar, mesoporous or organic.

Technical Field

The invention relates to the technical field of solar cells, in particular to design and preparation of a high-efficiency and stable perovskite/silicon two-end laminated solar cell.

Background

Perovskite and crystalline silicon tandem cells have attracted much attention in recent years due to the higher conversion efficiencies that can be achieved. The perovskite and crystalline silicon laminated cell is mainly combined in two modes, one mode is a perovskite and crystalline silicon cell two-end series laminated mode, and the other mode is a perovskite and crystalline silicon cell four-end laminated mode which is independent respectively. In the two-end laminated structure, the two-end laminated structure is more compatible with the preparation process of a large-scale assembly in the current photovoltaic market, and becomes the key point of the current perovskite and crystalline silicon laminated cell research. From 2015, the first perovskite/silicon crystal is preparedThe conversion efficiency of the tandem cell has been improved from 13.7% to 29.15% by the end-to-end tandem solar cell, which is far more than the highest efficiency of single crystal silicon, namely 26.7%. Major research units for perovskite/silicon two-terminal tandem solar cells that have been reported to have efficiencies exceeding 25% include the U.S. Stanford university McGehe group, the Switzerland Federal institute of technology Ballif group, the U.S. North Carolina university Huangjinson group, the Germany Helmholtz Berlin energy and materials research institute (HZB), and the England photovoltaics. It is worth pointing out that in the two-end laminated cell structure, according to kirchhoff's law, the current in the series structure design is limited to the minimum current value, that is, when the currents of the top and bottom cells are equal, the cell obtains the maximum current output, and the highest conversion efficiency is realized. Therefore, the current matching problem of the top and bottom cells is involved in the two-terminal stack design, so that stricter requirements are put on the absorption band gaps of the top and bottom cells. It is reported in the literature that to achieve a better match with the bandgap of crystalline silicon bottom cells (1.1eV), it is necessary to achieve current matching with a higher open circuit voltage using an appropriate wide bandgap perovskite cell. However, practical studies have found that the loss in open voltage of wide bandgap (greater than 1.65eV) perovskite cells is particularly severe compared to narrow bandgap (1.55eV) perovskite cells. From the results published to date, 27.1% higher conversion efficiency was achieved for the perovskite/crystalline silicon tandem cell of mcgehe group, university of stanford, usa, with an open circuit voltage of 1.886V and a short circuit current density of 19.12mA/cm²The fill factor was 75.3%. The top cell of the laminated cell is a perovskite cell with a band gap of 1.67eV, the single-junction cell obtains 20.42% of conversion efficiency, the open-circuit voltage is 1.217V, and the short-circuit current density is 20.18mA/cm²The filling factor is 83.16%, which is the highest cell efficiency obtained by the pin type wide band gap perovskite cell reported at present. According to the open-circuit voltage loss formula Eg/q-Voc, the open-circuit voltage loss is 460 mV. However, in current narrow band gap cells, the fipronil group also achieves an open circuit voltage of 1.2eV in perovskite cells with a reported band gap of 1.51 eV. And the larger the short-circuit current obtained is 23.5mA/cm due to the narrower band gap thereof²Finally, 21.9 percent of conversion efficiency is obtained, the open-circuit voltage loss of the conversion efficiency is only 310mV,much lower than the wide bandgap open voltage loss. In addition, numerous studies have also shown that wide band gap perovskite cells are more unstable. The wide-band-gap perovskite battery is mostly realized by adding more bromine, but the addition of the bromine can cause phase separation of the battery under the illumination condition, and is not favorable for the stability of the battery while the efficiency of the battery is not favorable.

In summary, the deficiencies of the existing wide band gap perovskite and crystalline silicon battery tandem cell technology can be summarized as follows: 1) wide band gap perovskite cells are chosen as top cells for current matching, but the open circuit losses of current wide band gap cells are more severe, resulting in stack cell open circuit voltages much lower than the ideal open circuit voltage. 2) The phase separation phenomenon of the wide-band-gap perovskite battery is easier to occur in the illumination process, the efficiency of the battery is not facilitated, the perovskite battery is made to be more unstable, and the practical application of the battery is not facilitated.

Disclosure of Invention

In order to solve the problems, the invention provides a perovskite with a proper narrow band gap as a top battery which forms a two-end laminated structure with a crystalline silicon battery, so that the perovskite/crystalline silicon laminated battery with higher efficiency and better stability is obtained. The following invention aims are achieved: 1) the problem of unmatched current caused by narrow band gap of the top battery is solved; 2) the narrow band gap is easier to realize and has smaller open-circuit voltage loss, so that the high open-circuit voltage advantage of the laminated battery is ensured; 3) compared with a wide-band-gap perovskite battery, the narrow-band-gap battery is more stable when being illuminated, and the stability of the laminated battery can be improved.

The technical scheme of the invention is as follows:

a high-efficiency stable perovskite/silicon two-end laminated solar cell takes a perovskite cell with a proper narrow band gap (between 1.40 and 1.65eV) as a top cell, and forms a laminated structure at two ends with a bottom crystalline silicon cell through an intermediate connecting layer; the structure design of the laminated cell is mainly embodied in that the areas of the top cell and the bottom cell are not equal, the area of the bottom crystalline silicon cell is slightly larger than that of the top perovskite cell, and the area ratio of the top cell to the bottom cell is 0.5-1.0. A proper narrow-band perovskite battery is adopted as a top battery of the laminated battery, the top battery can obtain larger current, and if the laminated battery still adopts the existing structure, the current of the top battery and the current of the bottom battery are not matched, so that the battery efficiency is influenced. The invention compensates the current of the bottom battery by increasing the area of the bottom crystalline silicon battery, and realizes the current matching of the top battery and the bottom battery. In addition, a perovskite battery with a narrower band gap is adopted as a top battery, so that a laminated battery with more stable illumination can be obtained.

The perovskite roof battery is an organic-inorganic hybrid perovskite material with a proper narrow band gap (between 1.40 and 1.65eV), or is an all-inorganic perovskite material; the components of the material are lead-based, tin-based or lead-tin mixed perovskite material. The perovskite roof cell is prepared by a solution method of two sequential depositions or one antisolvent deposition, or by an evaporation deposition or chemical vapor deposition method. The cavity material of the perovskite battery is inorganic NiO_XMnS or CuSCN, or is an organic material PTAA, Spiro-OMeTAD or Spiro-TTB; the electron layer transmission material is inorganic SnO₂Or TiO₂Etc. or organic material PCBM or C₆₀. The transparent electrode material on the upper surface of the perovskite top battery is ITO, IZO, IO H or IZO. The anti-reflection material on the transparent electrode material on the upper surface of the perovskite top battery is MgF₂LiF or SiO₂。

The middle connecting layer is made of transparent conductive film ITO or IZO, or amorphous silicon, microcrystalline silicon, nanocrystalline silicon or silicon oxygen material, or the middle connecting layer is made of transparent conductive adhesive to realize the connection of the top perovskite and the bottom crystalline silicon cell.

The crystalline silicon bottom cell is a planar silicon cell, a single-sided textured or double-sided textured silicon solar cell. The silicon cell is one of the following: n-type silicon chip, p-type silicon chip, CZ type or FZ type. The silicon cell is one of the following: a silicon heterojunction cell, TOP-Con cell, POLO cell, DASH cell, or homojunction cell; the homojunction battery is specifically a PERC, PERL or PERT battery.

The structure of the perovskite top battery and the structure of the bottom crystalline silicon battery select a pin battery structure or a nip battery structure. The structure of the perovskite battery is a planar type, a mesoporous type or an organic structure type.

In the preparation process of the battery, firstly, determining the absorption range and the obtainable integral current of the top perovskite battery through an external quantum efficiency tester (EQE); the effective battery area of the bottom crystalline silicon battery is properly increased through simulation calculation, and the current loss caused by narrowing of the band gap at the top is compensated, so that the current matching of the top battery and the bottom battery is realized; and after the areas of the top cell and the bottom cell are determined, preparing the top perovskite cell by adopting a solution method or a gas phase method, and finishing the laminated cell.

The invention has the advantages and positive effects that:

according to the invention, a perovskite battery with a proper narrow band gap is used as a top battery of the laminated battery, and the current loss of the bottom battery is compensated by adjusting the effective battery areas of the top battery and the bottom battery, so that the current matching of the top battery and the bottom battery is realized; meanwhile, on the premise of ensuring the high open voltage of the laminated battery, the invention improves the short-circuit current of the battery, thereby obtaining the perovskite/crystalline silicon laminated battery with higher efficiency; on the other hand, perovskite cells with narrow band gaps are more stable in light, so the design can also increase the stability of the tandem cell.

The mechanism analysis of the invention is as follows:

according to the invention, the problem of insufficient current of the bottom battery caused by reduction of the band gap of the top battery is compensated by increasing the effective absorption area of the bottom silicon battery, so that the short-circuit current of the laminated battery is further improved on the premise of ensuring smaller open-circuit loss of the top narrow-band-gap battery, and higher efficiency of the perovskite and crystalline silicon laminated battery is expected to be realized; in addition, due to the fact that the wide-bandgap perovskite battery has the phenomenon of illumination phase separation, the battery is extremely unstable in the illumination process, and the illumination stability of the laminated battery can be further enhanced by adopting the perovskite battery with a proper narrow bandgap.

Drawings

Fig. 1 is a schematic structural diagram of a pin-type narrow band gap organic-inorganic hybrid perovskite/silicon heterojunction tandem solar cell used in the invention.

Fig. 2 is a schematic structural diagram of a stacked solar cell adopting an nip type narrow band gap organic-inorganic hybrid perovskite/silicon heterojunction.

Fig. 3 is a schematic structural diagram of a pure tin-based inorganic perovskite/silicon heterojunction tandem solar cell used in the present invention.

Fig. 4 is a schematic diagram of a pin-type narrow band gap organic-inorganic hybrid perovskite/silicon heterojunction tandem solar cell used in the present invention, wherein a conductive adhesive is selected as a structural diagram of an upper cell connection layer and a lower cell connection layer.

FIG. 5 is a schematic structural diagram of a pin-type narrow band gap organic-inorganic hybrid perovskite/TOP-Con tandem solar cell used in the present invention.

Fig. 6 is a schematic structural diagram of a pin-type narrow band gap organic-inorganic hybrid perovskite/silicon heterojunction tandem solar cell used in the invention, wherein the silicon heterojunction is a single-side polished single-side textured structure.

Fig. 7 is a schematic structural diagram of a pin-type narrow band gap organic-inorganic hybrid perovskite/silicon heterojunction tandem solar cell used in the present invention, wherein the silicon heterojunction is a double-sided textured structure.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.