| Abstract:As a clean,renewable energy,solar energy has broad application prospects and development space.The research of crystalline silicon solar cells has been the hotspot of science and engineering.On the current research and development situation,studies of front electrode of crystalline silicon solar cells is more and more into the concrete,while the research of back electrode is almost blank stage.Therefore,to develop excellent back silver paste,and to realize localization of solar cells production technology and to break the passive situation of foreign monopoly,is of far-reaching significance to the development of science and technology and economy in our country.In this article,the preparation and properties of back silver paste of crystalline silicon solar cells is studied,Using chemical reduction to prepare spherical silver powder,using mechanical milling to prepare flake silver powder,using different content of organic carboxylic acid to prepare organic vehicle,this article mainly discusses the effect of silver powder,organic vehicle and sintering peak temperature to back silver paste sinter film and battery performance.The main results are as follows:1.The sinter film of back silver paste and performance of cells are different prepared with different forms of silver powder.The back silver paste prepared by flake silver paste is best,with uniform,intensive silver film and good conductivity,and the average cell photoelectric conversion efficiency is highest,17.430%.The properties of back silver paste prepared by spherical silver powder are after those prepared by flake silver powder, the average cell photoelectric conversion efficiency17.315%. The properties of back silver paste prepared by dendritic silver powder are worst.The sinter film has many big holes,so it can not form a good conductive channel.The square resistance is large,adhesion bad,and the average cell photoelectric conversion efficiency is15.733%.2.Using three different dispersion of flake silver powder to prepare back silver paste and polycrystalline silicon solar cell,the result shows that the back silver sinter film prepared by bad disperation silver powder is not intensive,and the adhesion force is not large,3.37N,electrical conductivity,the photoelectric properties of the cell is also poor, the photoelectric conversion efficiency is only16.389%.Back silver sinter film prepared by better disperation silver is better, electrical conductivity improves,the square resistance0.96mΩ/□,the average battery photoelectric conversion efficiency17.042%.And back silver sinter film prepared by good disperation silver is very ideal,all the performance best, the average cell photoelectric conversion efficiency is also the biggest,17.437%.3.Comparison of back electrode thick film and cell performance prepared by five kind of silver powder of different tap density(1.5g/cm3) shows that the back electrode made of the lowest tap density silver powder is of worst quality, the adhesion force of electrode film2.46N, the square resistance2.86mΩ/□,the average battery photoelectric conversion efficiency low,16.792%.As tap density increases,sinter film is better.Hole rate reduces and adhesion force improves,conductive performance is also better, battery photoelectric conversion efficiency higher.When the tap density of silver powder is3.5g/cm3, adhesion force,4.28N, the average battery photoelectric conversion efficiency is highest,at17.414%.4.The effect of the amount of organic carboxylic acid in organic vehicle to back silver sinter film characteristics and cell performance is discussed.When without organic carboxylic acid,back electrode is bad,holes many and big,adhesion force general,1.53N,and the average cell photoelectric conversion efficiency is low,17.120%.With the addition of organic carboxylic acid,the back silver sinter film has a certain improvement.Hole rate and surface square resistance reduce,and photoelectric conversion efficiency increases.When the content(w) of organic carboxylic acid was1.22%, the average photoelectric conversion efficiency is the largest, at17.336%.When organic carboxylic acid content continues to increase,sinter film quality begins to decline.The adhesion force reduces,and surface square resistance increases,and the photoelectric conversion efficiency reduces. 5.Choosing different peak sinter temperature can get different back electrode sinter film.When peak sinter temperatrueis730℃,silver paste sintering is not complete,so sinter film is not tight with many holes,and adhesion force is low,only1.76N,surface square resistance4.37mΩ/□,the average cell photoelectric conversion efficiency only16.067%.Gradually with the increase of peak sinter temperature,silver paste sintering,the sinter film quality improves.As the temperature is790℃,the cell performance is best,photoelectric conversion efficiency is the highest on average,17.336%.If temperature continues to rise,due to the burnt,the sinter film quality will become worse.When peak sinter temperature is820℃,the average cell photoelectric conversion efficiency is17.258%. |
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