NOVELTY - A solar cell comprises: a substrate having a p-n doped structure formed in it; and a material including a mixture of glass, organic medium, aluminum-containing material and additives, attached on back surface of the substrate.    USE - As a solar cell (claimed).    ADVANTAGE - The solar cell improves the requirements of thin solar cells to reduce the warping of silicon wafer, can be formed by a lead-free process, and has high conversion efficiency. The solar cell employs the back surface field (BSF) effect structure, by adding a special material or adhesive having a specific ratio of aluminum, glass and organic medium to the back surface of solar cells; which enhances the rigidity to solve problem of warping, changes structural stress, strengthens the overall solar cell structure, improves structure's abilities against strain or stress, effectively reduces wafer broken rate and improves performance of solar cells, and improves solar cell conversion efficiency. By using a composition of aluminum powder, glass frit having multiple glass compositions and organic medium as the adhesive material, the structural stress is reduced and substrate deformation is prevented. The changing of the material or adhesive and utilization of glass frit, improves the degree of deformation, and raises the conversion efficiency of solar cells. The formation of aluminum-silicon alloy layer on the back surface of the silicon wafer, improves the structural stress of thin solar cells. The mixing of different glass compositions and additives alters the thermal expansion coefficient i.e. changes the expansion coefficient under room temperature, such that the expansion coefficient is modified to be near the expansion coefficient of silicon substrate. Also, as the solar cell only requires adding a specific ratio of aluminum paste material to achieve better performance; as compared to the prior art laser-fired contact (LEC) process and screen printing method that utilizes low wrap aluminum paste and halftones with high mesh count followed by LEC process; the process not only reduces wafer broken rate during production process, but also reduces production cost and improves conversion efficiency. The solar cells can be formed by mass production by printing of the aluminum paste to the solar cells.    DETAILED DESCRIPTION - A solar cell comprises: a substrate having a p-n doped structure formed in it; and a material including a mixture of glass, organic medium, aluminum-containing material and additives, attached on back surface of the substrate. The mixture of glass includes at least two main compositions, where at least two main compositions include first glass composition and second glass composition. The aluminum-containing material has aluminum powder content of (60-80 mass%), and has a purity of 90-99.99%. The average grain size of the aluminum in aluminum-containing material is 1-20 mu m. The additives are present in an amount of (less than 5 mass%). The content of organic medium is (20-35 mass%). The organic medium includes ether class solvent (60-90 mass%), cellulosic resin (10-20 mass%), and a leveling agent, rheological agent or thixotropic agent (1-5 mass%). An INDEPENDENT CLAIM is included for an adhesive material comprising: a mixture of glass, organic medium, material with aluminum and additives, where the main compositions of the mixture of glass include Al2O3, Bi2O5, B2O3, SiO2, PbO, Tl2O3 or ZnO, and further include Fe2O3P2O5, MgO, Ga2O3, Li2O, Na2O, ZrO2, AgO, Sc2O5, SrO, BaO, CaO, Pd, Pt, or Rh.