*Conductive Powder Synthesis Technology for Improving Electrical Conductivity by One-Pot… DOI: http://dx.doi.org/10.5772/intechopen.108937*

structure using the spray pyrolysis process has been reported in several papers [21–24]. Composite powders of this structure are manufactured by mixing silver nitrate and a salt comprising glass in a precursor solution under the same process of synthesizing powder (pure Ag) through ultrasonic spray pyrolysis process, as shown in **Figure 1**. It is analyzed that during the pyrolysis and melting process, the glass is pushed into the shell due to the density difference between glass and Ag (glass: 2.4–2.8 g/cm3 , Ag: 10.5 g/cm3 ), forming a core-shell structure. Structural analysis of these particles showed that glass is present on the surface by comparing the composition of the shell and core in the DES analysis using STEM, as shown in **Figure 2**.

**Figure 2.** *Element mapping and EDS results of the composite powder [21].*

**Figure 3.** *SEM photographs of surfaces and specific resistivity of silver conducting films sintered at a temperature of 450°C [21].*

For the electrode layer thus formed, the effect of the composite powder on the densification of the electrode was analyzed through SEM and resistivity analysis as shown in **Figure 3**. As can be confirmed from the SEM analysis, in the electrode layer using only Ag powder, there are several pores without complete connection between the Ag particles, whereas in the case of the electrode layer using the composite powder, the pores on the surface of the electrode layer are significantly reduced, and the contact force between the electrode powders is improved. The specific resistances of the electrodes formed using Ag powder, Ag powder and spherical glass powder mixture, and Ag-glass composite powder were 19 μΩ∙cm, 9 μΩ∙cm, and 3.6 μΩ∙cm, respectively. The specific resistivity was lowered to approximately 50% compared to using only Ag, and approximately 40% compared to the composite powder through ideal

#### **Figure 4.**

*SEM photographs of surfaces of silver conducting films with various contents of glass sintered at a temperature of 400 and 550°C [24].*

*Conductive Powder Synthesis Technology for Improving Electrical Conductivity by One-Pot… DOI: http://dx.doi.org/10.5772/intechopen.108937*

**Figure 5.**

*Specific resistance of silver conducting thick films as a function of sintering temperature and content of glass additive.*

dispersing glass frit. This shows that the composite power has the effect of improving conductivity by enhancing the density of the electrode.

Although glass frit can be advantageous in facilitating sintering, it is an amorphous oxide, and should be applied in a minimum amount. Therefore, studies have been reported on the content of glass compared to Ag. Since composite powders can ideally disperse glass and Ag, a previous study observed the density of the electrode according to the glass wt.% through SEM. Further, the effect of glass content on the heat treatment temperature for the electrode was also investigated [24]. As shown in **Figure 4**, an increase in the glass content had a positive effect on the electrode density improvement, and the lowest glass content varied depending on the post-heat treatment temperature. In the results of this study, 5.3 and 2.3 μΩ∙cm showed the lowest resistivity values at post-treatment temperatures of 400 and 550°C, respectively, as shown in **Figure 5**. Moreover, the glass content was 3 wt.% and 1 wt.%.
