Fig. 1. Packaging process of high-power LED with nano-silver sintering

Fig. 2. Properties of Ag paste under various sintering temperatures. (a) Electrical resistivity; (b) shear strength; (c) XRD image of nano-silver paste after sintering at 200 ℃; (d) fracture morphology of bonding layer

Fig. 3. Cross-sectional images of LED module. (a) Cross-section of LED under optical microscope; (b) SEM image of nano-silver bonding layer

Fig. 4. Thermal properties of sintered LED with Ag NPs and SAC305. (a) Thermal image of Ag NPs sintered LED at 350 mA; (b) thermal image of SAC305 sintered LED at 350 mA; (c) working temperatures of LED under various currents; (d) junction temperature change of LED at 350 mA

Fig. 5. Thermal resistance of sintered LED with different pastes. (a) Differential thermal resistance; (b) integral thermal resistance

Fig. 6. Junction temperature change of LED under different driving currents and lighting pictures. (a) Junction temperature change;(b) picture of LED sintered with Ag NPs; (c) picture of LED sintered with SAC305

Fig. 7. Spectra of sintered LEDs at different currents. (a) Ag NPs; (b) SAC

Fig. 8. Thermal performance of LED sintered with different solder pastes after operated at 100 ℃ for 500 h. (a) Thermal resistance; (b) junction temperature change

Fig. 9. Photoelectric conversion efficiency of LED sintered with different solder pastes after operated at 100 ℃ for 500 h