Influence Of Laser Process On Photoelectrical Properties Of Crystalline Silicon Solar Cells

As a safe、clean and inexhaustible reproducible new energy, Photovoltics is considered to be one of the main way to solve the world energy crisis and environment problems. China’s PV cells output has been the dominant first in the world since2007. However, domestic studies on solar cells are relatively short, so the foundation of research and development is weak and the technology accumulations are still devoid. This situation serious restricts development of the PV industry.Crystalline silicon solar cells which accounts for more than85%worldwide PV market is also the main force of our country’s PV industry, so develop technologies of crystalline silicon solar cells became very important. In this thesis, researches of laser technologies applied in the fabrication of industrial crystalline silicon solar cells are carried to improve efficiency and control cost. Specific content is as follows:(1) Laser texturization of multicrystalline silicon wafer. In this work, the mc-Si surface was first textured by a1064nm wavelength laser, and then followed by a step of chemical solution etching to remove the laser induced surface damage layer. Through optimizing parameters of laser texturization and chemical etching, we obtained an antireflection structure of concave-convex pentahedra. The structure has very good light trapping effect, making the surface reflectivity down to8.0%in the range of300and1100nm. A surface damage layer was formed after the laser texturization step and chemical etching cannot remove it completely. To solve this problem, a passivation layer deposited by ALD was introduced and a better electrical property of wafer was get.(2) Intersected laser doped selective emitter silicon solar cells. This work is first designed to solve the difficult alignment between the screen-printed Ag gridlines and the high doped selective emitter. The core of our work is the intersected laser selective doping, that means the selective highly doped emitters are intersected to the Ag gridlines. First a homogeneous shallow doped emitter was gained through POCl3diffusion followed by a laser selective doping, and then the Ag gridlines were screen-printed intersecting to the highly doped area. Our work can perfectly solve the alignment problem while making LDSE solar cells and have a dramatically cell performance improvement (from14.39%to17.74%) owing to the improved electrical contact and FF properties.