Solar cell and preparation method thereof

Abstract

The embodiment of the invention provides a solar cell and a preparation method thereof, the solar cell comprises a crystalline silicon substrate, and a first tunneling film layer, a doped polycrystalline silicon layer, a first passivation layer, an anti-reflection layer and a mask layer are prepared on one surface of the crystalline silicon substrate; and a second tunneling thin film layer, a heavily doped polycrystalline silicon layer, a second passivation layer, an overweight doped polycrystalline silicon layer and a transparent conductive layer are prepared on the other surface. Good chemical passivation and field effect passivation on the surface of the doped polycrystalline silicon layer are realized by introducing the passivation layer, the loss of carriers caused by recombination on the polycrystalline silicon layer is reduced, and the effective output of photon-generated carriers is improved; through introduction of the overweight doped polycrystalline silicon layer, field effect passivation of one surface is further enhanced, certain power is provided for output of photon-generated carriers to an external circuit through potential difference values generated by different doping concentrations, effective output of the carriers is increased again, and therefore the conversion efficiency of the solar cell is effectively improved.

Description

technical field [0001] The invention relates to the technical field of solar energy, in particular to a solar cell and a preparation method thereof. Background technique [0002] Crystalline silicon solar cells are the most mature and widely used solar cells, accounting for more than 90% of the photovoltaic market, and will occupy a dominant position for a long time in the future. Among the many factors affecting the photoelectric conversion efficiency of crystalline silicon solar cells, the recombination of the contact between metal electrodes and crystalline silicon is the key factor, which is considered to be the last limiting factor close to the theoretical limit efficiency. At present, the use of a tunnel oxide layer to passivate the metal contact structure can significantly reduce the recombination of the metal contact area, and at the same time have good contact performance, which can greatly improve the conversion efficiency of crystalline silicon solar cells. Compa...

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Problems solved by technology

The inventors of the present application have found in practice that the doped polysilicon layer in the contact structure provides field-effect passivation for the crystalline silicon itself and is responsible for forming an ohmic contact with the electrodes of the external circuit, but actually it still belongs to the photogenerated carrier of the solar cell The conductive carrier has a large number of recombination centers due to its own structural defects, which still has great restrictions on the final transfer of carriers to the external circuit, which reduces the conversion efficiency of solar cells to a certain extent.

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