Preparation And Characterization Of Silver Paste Glass Powder For Solar Cells

With the development of society and the continuous advancement of human beings,the demand for energy is increasing,while the traditional fossil energy is limited,and the traditional fossil energy reserves in China are far below the world average;on the other hand,with the concept of environmental protection Continuously strengthening,the development of clean and environmentally friendly renewable energy has become the trend of future energy development,and solar energy is an inexhaustible renewable energy,with the advantages of clean,wide application and sufficient resources,in our long-term energy strategy.Occupy an important position.In this paper,the silver paste glass powder for solar cells is used as research and development object.The glass powder for the silver paste on the front side of the solar cell and the silver paste on the back side is discussed.It is intended to be used in the preparation of the front and back electrode pastes of solar cells.The glass powder is developed by high-temperature melting,and the glass liquid is water-quenched to obtain coarser glass particles,and then the ultra-fine glass powder satisfying the requirements is prepared by air-jet grinding.The glass powder of Bi-B-Si-based positive silver and the glass powder of Bi-B-Zn-Si-based back silver were prepared in the whole subject.The melting bismuth material of silver paste glass powder and the main components of the glass system were separately studied.And the effect of mixing alkali metal and alkaline earth metal on the properties of silver back glass powder;using differential thermal analysis(DSC),X-ray diffraction analysis,infrared spectroscopy(IR),Raman spectroscopy,scanning electron microscopy(SEM+)EDS)and other characterization methods were used to analyze the properties and related mechanisms of the glass powder itself.The thermal expansion coefficient and expansion softening temperature of the glass block were analyzed by a thermal dilatometer.The study yielded the following results:(1)The best tantalum material for melting Bi-based silver paste glass powder is corundum crucible,but the use of corundum crucible will introduce Al2O3 during the melting process,and the excessive content of the glass Al2O3 may cause phase separation and melting difficulties.This experiment found that the mass fraction of Al2O3 in the glass system should be controlled within 8%.(2)In the Bi-B-Si-based positive silver glass system,the increase of SiO2 content in the design component can improve the chemical stability and thermal stability of the glass,but also increase the glass transition temperature Tg and melting temperature of the glass system.,to reduce the expansion coeficient of the glass,so when applied to the positive silver glass powder,the mass fraction of SiO2 is preferably not more than 10%.With the decrease of Bi2O3 content and the increase of B2O3 content,[BiO6]of octahedral structure gradually changes to[BiO3]of triangular pyramid structure,[BO3]of triangular structure gradually transforms to[BO4]of tetrahedral structure,bridge oxygen As the number of bonds increases,the glass structure becomes compact,which causes the Tg,TP,and Tf values of the glass to rise,the expansion coefficient of the glass to decrease,and the thermal stability and chemical stability of the glass to be improved.(3)In the glass system of Bi-B-Si-based positive silver,when Na2O is added alone,the expansion coefficient of the glass system becomes larger,and the values of Tg5 TP,and Tf decrease.When Na2O and K2O are mixed,it appears.The mixed alkali effect",the thermal stability and chemical stability of the glass are greatly improved.In the system of the positive silver glass system,the optimum mass ratio is:74Bi2O3-10.75B2O3-6.1SiO2-5.6Al2O3-1.8ZnO-0.75CeO2-0.5Na2O-0.5K2O.(4)In Bi-B-Zn-Te back silver glass,replacing a small amount of TeO2 with a different mass of B2O3 or ZnO2 will cause the[BO4]of the tetrahedral structure in the glass to gradually transform into a triangular structure[BO3],When the non-bridged oxygen bond is increased and the glass structure becomes loose,the glass transition temperature Tg,the crystallization temperature Tp,and the expansion softening temperature Tf of the glass are lowered,and the expansion coefficient is also increased.However,after replacing the equal mass fraction of Bi2O3 with a small amount of TeO2.the structure of[BiO6]and[BO4]in the glass structure will increase,the bridge oxygen bond in the glass structure will increase,and the glass network structure will become more compact,thus making Tg?Tp And Tf has improved,the coefficient of expansion decreased,comprehensive differential heat,thermal stability,chemical stability and cost analysis,the best mass ratio of the base glass powder system of glass powder for back silver is:67.9Bi2O3-9B2O3-9.5ZnO-4.7TeO2-5.6Al2O3-3.3SiO2.(5)In the back silver glass system,after adding a small amount of MgO alone,the expansion softening temperature gradually increases with the increase of MgO content,and the expansion coefficient decreases continuously.After adding equal mass fractions of CaO and MgO,there is a "appearance".The trend of double alkaline soil effect,thermal stability and chemical stability are enhanced,but the effect is not obvious,probably because the difference in radius between Ca2+ and Mg2+is small.(6)When grinding glass frit,the use of jet milling is more efficient than mechanical ball milling,and the time-saving,milled glass powder has a finer particle size and a more uniform particle size distribution.