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CN-119677206-B - Process for reducing thermal diffusion open pressure loss of molybdenum oxide composite silicon heterojunction solar cell

CN119677206BCN 119677206 BCN119677206 BCN 119677206BCN-119677206-B

Abstract

The molybdenum oxide (MoO X ) composite silicon heterojunction battery adopts transition metal oxide molybdenum oxide with wide band gap and high work function as a hole selection layer, reduces the absorption of a light-in surface, has higher hole carrier export capability, and avoids parasitic absorption caused by doping of the traditional heterojunction battery selection layer, but the molybdenum oxide has poor thermal stability, and can diffuse oxygen to silicon when exceeding 130 ℃, so that the molybdenum oxide is a main obstacle for realizing that the MoO X composite silicon heterojunction solar battery is applied to a screen printing process to obtain a larger light-in surface area so as to obtain higher short-circuit current. Therefore, a layer of ZnO is inserted between a-Si and H (i)/MoO X , and is annealed after screen printing, so that the ZnO prevents the mutual diffusion influence of MoO X and oxygen elements of a passivation layer, and the open voltage loss is restrained.

Inventors

  • DING BOWEN
  • ZHOU YURONG
  • LIU FENGZHEN

Assignees

  • 中国科学院大学

Dates

Publication Date
20260508
Application Date
20240624

Claims (5)

  1. 1. The preparation method of the silicon-based heterojunction solar cell using the screen printing MoOx compound is characterized by comprising the following steps of: (1) Adopting a Plasma Enhanced Chemical Vapor Deposition (PECVD) method, using SiH 4 、H 2 as a reaction gas, depositing and preparing a 3-5nm intrinsic amorphous silicon film on one surface of an n-type crystalline silicon substrate, and then using SiH 4 、H 2 、PH 3 and CO 2 as reaction gases, depositing a 15-20nm n-type microcrystalline silicon-oxygen film on the intrinsic amorphous silicon film, namely a back surface and an n surface; (2) Adopting a PECVD method, taking SiH 4 、H 2 as a reaction gas, depositing and preparing a 3-5nm intrinsic amorphous silicon film on the other surface of the crystalline silicon substrate, and then performing magnetron sputtering on the 2-3nm ZnO film; (3) A hot wire oxidation sublimation method (HWOSD) is adopted to deposit a 9nm MoOx film on ZnO; (4) Preparing a hydrogen doped ITO film by adopting Reactive Plasma (RPD) on two sides on the basis of the steps (2) and (3); (5) Evaporating silver on the n surface after the step (4) is completed; (6) And screen printing is adopted, silver grid lines are screen printed on the ITO film on the MoOx surface and cured, and the battery preparation is completed.
  2. 2. The method of claim 1, wherein the flow rate of the Ar gas in the magnetron sputtering in the step (2) is 30sccm, and the growth rate is controlled to be 8nm/min or less.
  3. 3. The method of claim 1, wherein the oxygen flow during the growth of step (3) is 10sccm.
  4. 4. The method according to claim 1, wherein the TCO of step (4) has a thickness of 70nm on the p-side and 120nm on the n-side.
  5. 5. The method of claim 1, wherein the silver grid lines produced by screen printing in step (6) have a fine grid line width of 30 microns and a main grid line width of 600 microns.

Description

Process for reducing thermal diffusion open pressure loss of molybdenum oxide composite silicon heterojunction solar cell Technical Field The invention belongs to the field of solar cells, and relates to a novel structure and a process method of a composite silicon-based heterojunction solar cell with improved molybdenum oxide thermal stability. Background With the rapid development of global economy, energy demand has increased dramatically, resulting in a rapid decrease in fossil energy reserves. The difficulty and cost of exploitation of traditional energy sources such as coal, petroleum and natural gas are continuously increased, and a great number of countries face a serious energy shortage problem. Meanwhile, environmental pollution and climate change are aggravated due to excessive dependence on fossil fuel, so that the energy crisis threatens economy and stability, and constitutes a great challenge for ecological environment and human health. The energy crisis is solved, global effort is needed, energy structure transformation is pushed, and a sustainable energy development path is found. Crystalline silicon solar cells play a vital role in modern energy conversion and are widely applied to various solar power generation systems, and are favored due to high-efficiency and stable performance and long service life. Particularly, the heterogeneous crystalline silicon solar cell remarkably improves photoelectric conversion efficiency and reduces energy loss by combining amorphous silicon and crystalline silicon. The innovative technology of the solar energy power generation system not only improves the overall power generation efficiency, but also promotes the progress of the solar energy technology, and provides powerful support for realizing more efficient and more environment-friendly energy utilization. In order to enable the existing silicon-based heterojunction battery to have higher short-circuit current. However, the parasitic absorption of the doped amorphous silicon and the passivated intrinsic amorphous silicon of the current selection layer can reduce the short-circuit current of the SHJ battery, and the doping difficulty of the p-type amorphous silicon can limit the work function change, which is a main obstacle for improving the efficiency of the SHJ battery at present. The short circuit current of the current high efficiency SHJ battery is about 40mA/cm 2, and the high work function wide bandgap oxide is an effective potential solution for further reducing parasitic absorption loss and limited energy level adjustment caused by the a-Si: H layer. The patent adopts a molybdenum oxide (MoO X) compound crystalline silicon heterojunction battery with a ZnO/MoO X structure. The structure utilizes the wide band gap and high work function of MoO X, and simultaneously utilizes ZnO to prevent oxygen in MoO X from diffusing at the curing temperature of screen printing grid lines, thereby reducing parasitic absorption loss, protecting MoO X and not affecting hole transmission. Disclosure of Invention The invention aims to solve the problem of MoO X thermal stability failure in a molybdenum oxide compound crystalline silicon heterojunction solar cell in the process of curing a screen printing grid line. The embodiment of the invention provides a preparation method of a molybdenum oxide surface silk screen grating linear compound silicon-based heterojunction solar cell. The method comprises the following steps: (1) Preparing an intrinsic amorphous silicon film with a thickness of 3-5nm by adopting a Plasma Enhanced Chemical Vapor Deposition (PECVD) method and using SiH 4、H2 as a reaction gas, depositing an n-type microcrystalline silicon oxide film with a thickness of 15-20nm on the intrinsic amorphous silicon film by using SiH 4、H2、PH3 and CO 2 as reaction gases (2) Adopting a PECVD method, taking SiH 4、H2 as a reaction gas, depositing and preparing a 3-5nm intrinsic amorphous silicon film on the other surface of the bottom of the crystalline silicon village, and then continuously depositing a 2-3nm ZnO film on the intrinsic amorphous silicon film by a magnetron sputtering method; (3) Growing a molybdenum oxide film with the thickness of 9nm on the ZnO film in the step (2) by adopting a thermal dead oxidation sublimation method; (4) Preparing a 70nm ITO film on the molybdenum oxide film in the step (3) by adopting Reactive Plasma (RPD); (5) Depositing a 120nm ITO film on the n film in the step (1) by adopting Reactive Plasma (RPD); (6) Thermally evaporating the silver electrode after the step (5) is completed; (7) And (3) on the basis of the step (6), screen printing is adopted on the back surface, ag electrodes are screen-printed on the p-surface ITO film area, and sintering and curing are carried out at 200 ℃, so that the battery preparation is completed. The preparation method of the novel molybdenum oxide compound silicon-based heterojunction solar cell of the screen printing grid line electrode a