Silver nanosheets with a two-dimensional sheet structure exhibit excellent electrical, optical and chemi-cal properties and are widely used in electronics, catalysis, biology and other fields. The diameter of silver nanosheets prepared by chemical reduction methods is usually less than 1 μm, and the yield is low. In order to solve the above problems, large-sized silver nanosheets were prepared by a chemical reduction method with guanine as the structural inducer and silver nitrate as the silver source. The optimized preparation conditions were as fol-lows:at 0℃, the dropping speed was 1. 0-1. 3 mL/min, the stirring speed was 300 r/min, and the concentra-tions of guanine and AgNO3 in solution B were 16. 56 mmol/L and 0. 50 mol/L, respectively. Under the optimal conditions, large-sized silver nanosheets with a diameter of 10 -20 μm were prepared, and the yield of silver nanosheets per unit volume of reaction solution was as high as 15 g/L. The results of X-ray diffraction ( XRD) and Raman spectroscopy show that the growth mechanism of silver nanosheets is that the carbonyl oxygen atoms of gua-nine molecules are selectively adsorbed on the (111) crystal plane of silver crystals to form a coating, and the re-duced silver atoms are deposited on the ( 110 ) and ( 100 ) crystal planes to form silver nanosheets by lateral growth . A conductive adhesive was prepared using the large-sized silver nanosheets prepared under the optimal con-ditions as fillers with diethylene glycol monobutyl ether and ethanol as solvents. The percolation threshold of the re-sulting materials was as low as 30％ -40％( mass fraction) .
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