Silicon-based Solar Cells Positive Silver Slurry Preparation And Research

In this paper,experimental studies on preparing the conductive silver paste of silicon solar cells and kinds of silver paste performances and preparing of silver powder,glass powder,organic carrier,which focus on the silver powder,glass powder by chemical reduction and high-temperature melting respectively,were carried out.Micro-sized silver power was prepared from AgNO3power by chemical reduction,and experimental optimization processes were showed by orthogonal experiment.The silver sol was obtained from silver nitrate via chemical reduction under ultrasonic wave and alkaline environment using polyethylene glycol (PEG-6000) as dispersant and alcohol as antifoam agent,and after agitation,the sol was filtered,washed and dried at constant temperature. Effects of reagents adding order,pH,dosage of alcohol, dosage of disperser were investigated.And the silver powders were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM),respectively.Results show that with0.3mol/L AgNO3solution, ethanol/reaction liquid=v%25,T=40℃,pH=7and15min ultrasonic wave, spherical silver power about1.13μm with narrow particle size distribution was fabricated.Lead-free glasses in the Bi2O3-B2O3-SiO2-Al2O3quaternary system were studied. The comprehensive performances of lead-free glass powder were improved with addition of a suitable amount of MnO2,MgO,NaF,TiO2and SnO2.The effects of various oxides on the soften point and viscosity of glass powder were studied in details,and focused on the effects of SnO2on softening temperature of the glass frits,some explanations about the effects of SnO2on the soften point of glass frits were given out. By using this formulation, the glass frits which low temperature and lead-free glass frits which softening temperature is462℃was successfully prepared,the XRD pattern of this glass frits showed that lead-free frits has the glass typical amorphous structure and the performance of forming glass was very good and the range of extension was very wide. And planetary ball milling of glass powder was studied.The glass frits about2.4μm with narrow particle size distribution was fabricated in condition that ball-to-water-to-powder weight ratio2.5:0.8:land16h.In this experiment,the mixed solution including terpineol,butylcarbitol,dibutyl phthalate,was prepared as organic solvents,and ethyl cellulose as organic resin by studying on evaporation mechanism of the organic carrier,the effects of the printed pattern on the percentage of mixed solution were studied.Finally,silver paste was fabricated by uniformly mixing with silver powder,glass powder and organic carrier,and silver electrodes of solar cells were made through a series of steps including artificial silk-screen printing, advection, drying, sintering. The effects of the sintering temperature,sintering time and glass powder content,silver grading on the silver film adhesion and square resistance respectively,were studied in details,and the relevant mechanism was analyzed,and the effects of the glass powder content on the solderability performance were studied,too.