A kind of low recombination firing-through screen-printing aluminum (Al) paste is proposed in this work to be used for a boron-diffused N-type solar cell front side metallization. A front side fire-through contact (FTC) approach has been carried out for the formation of local contacts for a front surface passivated solar cell. With a low contact resistivity (ρc) of 1.0 mΩ·cm2, good ohmic contact between the boron-doped front surface of the silicon sample and the Al paste was realized. To obtain a good energy conversion efficiency, a balance can be achieved between the open circuit voltage (Voc) and contact resistivity (ρc) of the cell by combining suitable Al powders and appropriate additives. The detailed micro-contact difference in Si/metallization between the firing-through Al paste and silver-aluminum (Ag-Al) paste was analyzed. The dark saturation current density beneath the metal contact (J0, metal) of the Si/metallization region using our firing-through Al paste was discussed, which was proven to be 61% lower than using Ag-Al paste. The pseudo energy conversion efficiency of the cell using Al paste measured by Suns-VOC was also higher than using Ag-Al paste. The role of Al paste in low surface metal recombination is discussed. The utilization of this new kind of Al paste was much cheaper and more convenient, compared to the traditional process using Ag or Ag-Al paste.

Melamine sponge (MS) has the characteristics of multilayer network structure, high porosity, adjustable pore structure, and low price, which is considered to be an ideal material for oil leakage treatment. Here, a facile, economical, environmental friendly, and one step reaction was developed to fabricate Ag nanoparticles (NPs) decorated MS composite with tannic acid (TA) as a reducing agent. By reduction reaction, the super-hydrophobic and super-oleophylic surface of the MS–TA–Ag composite was formed, demonstrating a single selectivity for oil and water. Thus, the adsorption capacity of MS–TA–Ag composites for various oils/organic solvents can reach 48~129 times its own weight and and display superior efficiency to separate oil/organic solvent from the water. In addition, the MS–TA–Ag composite has stable super-hydrophobicity and reusability. It is exciting that modified MS exhibits excellent chemical stability properties after a long processing time with strong alkali, strong acids, and salt solutions. The simple strategy provides a method for the preparation of large-scale oil spill cleaning and recovery materials.