太阳能电池正面银浆用高分散超细银粉的制备

Preparation of Highly Dispersed Ultrafine Silver Powders for Silver Paste on Solar Cell Front

以AgNO3为原料,抗坏血酸为还原剂,羧甲基纤维素为分散剂,采用化学液相还原法制备超细银粉,重点研究了加料方式、分散剂用量、体系pH值和反应温度对银粉特性的影响。结果表明:加料方式和分散剂用量均对银粉分散性有直接影响;随着pH值的增加,银粉的粒度逐渐减小但分散性降低;而反应温度对银粉性能的影响很大,在30℃、35～45℃、50℃不同温度下,银粉形貌依次为球形、类球形、树枝状,其分散性和振实密度逐渐降低。最佳工艺条件如下:加料方式为将AgNO3溶液加入到还原溶液中,分散剂与还原剂质量比为0.015,控制pH值为2,反应温度为30℃。在此工艺条件下,制备出高分散性、振实密度4.6g/mL、平均粒度3.95μm的超细银粉,可满足太阳能电池正面银浆材料的要求。

The ultrafine silver powders were prepared from AgNO3 by chemical liquid-phase reduction,with ascorbic acid as the reducing agent and carboxymethyl cellulose as the dispersant. The effects of feeding way,dispersant dosage,pH value and reaction temperature on silver powder properties were emphatically researched. The results show that feeding way and dispersant dosage directly affect the dispersity of silver powders. As pH value increases,the reaction particle size of silver powders becomes smaller while the dis- persity decreases. The reaction temperature shows a significant influence on the properties of silver pow- ders. Spherical,sphere-like and dendritic silver powders are respectively obtained at 30 ℃, 35~45 ℃ and 50 ℃. Meanwhile,the dispersity and tap density of silver powders decrease when the temperature increa- ses. The optimized preparation conditions are：the feeding way of adding AgNOa solution into reducing so- lution,m（CMC）/m（C6 He O6） value of 0. 015, pH value of 2 and reaction temperature of 30℃. Under the conditions,the highly dispersed ultrafine silver powders,with a tap density of 4.6 g/mL and a mean parti- cle size of 3.95 μm,can be prepared to meet the requirements of silver paste on solar cell front.