Synergistic effect of graphene on improving laser sealing performance of inorganic glass solder

Inorganic glass solder has high application potential in laser sealing of electronic components, but its ability to convert light energy into heat energy still needs to be further improved. This paper demonstrates that graphene can help bismuthate glass solder perform much better in laser sealing. As demonstrated here, the shear strength (bonding strength) of the seal had more than doubled. However, in order to obtain the maximum shear strength, the optimum mass content of graphene should be ca. 0.5–1.0%, because cracks may form at the interface between graphene and glass, thus reducing the mechanical strength. The further results show that the participation of graphene led to improvement in the photothermal conversion efficiency of the glass solder, and favorable changes in the flow characteristics of the glass melt. When only 1% graphene was added, the photothermal conversion efficiency of the glass solder under 915 nm laser increased from 48.4 to 60.1%, which is very close to 64.3% of graphene alone. In addition, the contact angle between glass melt and quartz glass chip was reduced from around 140° to 25°, implying more beneficial fluidity and wettability.