The Effect Of Light Source On Light Induced Plating In Crystalline Silicon Solar Cells

At present,80%of solar cells are crystalline silicon materials,and the latest crystalline silicon solar cell energy conversion efficiency can reach 26.33%.In order to obtain high quality,high efficiency of crystalline silicon solar cells,crystalline silicon technology is the key.Front side electrode copper plating technology that use copper instead of silver electrode can effectively reduce the shadow loss and contact resistance and reduce the costs,in which one of the most critical steps in copper plating technology for front side electrodes is the preparation of copper diffusion barriers,and which are mainly prepared by light-induced plating(LIP).LIP combines the electroplating technique and the characteristics of the photovoltaic effect of the cell chip itself to carry out metal plating on the front side gride line electrode.In the early initial stage of our lab,we have developed a grating technique without laser grooving and photolithography.The mask was utilized to form the grating shape of the light,and then the wire was formed directly with LIP.So the light source becomes critical in the preparation of LIP diffusion barrier layer.Previous studies have found that LIP can form a uniform coating on silicon wafers and can form an ohmic contact with silicon after annealing,where Co is selected as the diffusion barrier.The intensity and wavelength range of the light source can affect the energy conversion efficiency of solar cells in light induced plating.In the process of LIP,the interfacial barrier of solution and semiconductor is directly related to the photoelectric effect of crystalline silicon solar energy.Therefore,the intensity of light source and the wavelength have a direct effect on the deposition rate of LIP.In this paper,we mainly study the influence of light intensity and wavelength of LIP,and the preparation of the metal cobalt gate line diffusion barrier by LIP.The photocurrent density of LIP was calculated by measuring the voltage with an electrochemical workstation.The effects of monochromatic light,optical power density and solution concentration on the LIP were observed.When the optical power density is located between 5 mW/cm2 and 80 mW/cm2,with the increased of illumination intensity,the photocurrent density increased.When the solution concentration is between 0.05 M and 0.25 M,the photocurrent density grows with the increase of the solution concentration.We can can choose white light and red light in the wavelength range of 580 nm to 690 nm when LIP cobalt.The design of the mask is directly related to the shape of the front side electrode,so its design is also very important.Using the optimized masking to LIP cobalt lines to characterize its morphology(SEM),it was found that a uniform and dense cobalt coating was formed on the substrate with a finger width of about 100 um and a busbar width of about 1 mm.In this paper,the influence factors of LIP and the design of mask have made a meaningful exploratory study in laser-free electroplating technology without laser slotting...