Weiping Gan

Effect of silver powders on a low curing temperature silver conductive adhesive

In this paper, some different types of epoxy electrical conductive adhesive (ECA) are prepared and investigated. Flake silver, spherical silver and the mixture of them are employed to fabricate ECA samples, respectively. With different percentage of filler loading, the morphology, adhesion, hardness, resistivity and differential scanning calorimeter (DSC) test of the silver filled ECA samples are compared and analyzed. By comparing the samples, it is found that the adhesion do not change a lot from each other. While in terms of hardness and resistivity, flake silver shows a better performance than spherical silver. The scanning electron microscopy figures of the ECA samples reveals that the mixed silvers have a better filler distribution and form a more dense conductive network than the single component—flake silver or spherical silver. Furthermore, when the ratio of flake silver to spherical silver reaches a suitable value, the ECA achieves the optimum electrical conductivity. Finally, the DSC test result shows the appropriate curing temperature for the ECAs.

Preparation of silver-coated glass frit and its application in silicon solar cells

A simple electroless plating process was employed to prepare silver-coated glass frits for solar cells. The surface of the glass frits was modified with polyvinyl-pyrrolidone (PVP) before the electroless plating process. Infrared (IR) spectroscopy, field emission scanning electron microscopy (FESEM), and x-ray diffraction (XRD) were used to characterize the PVP modified glass frits and investigate the mechanism of the modification process. It was found that the PVP molecules adsorbed on the glass frit surface and reduced the silver ions to the silver nanoparticles. Through epitaxial growth, these nanoparticles were uniformly deposited onto the surface of the glass frit. Silicon solar cells with this novel silver coating exhibited a photoelectric conversion efficiency increase of 0.33%. Compared with the electroless plating processes, this method provides a simple route to prepare silver-coated glass frits without introducing impurity ions.

Effect of solid content on performance of conductive silver paste for crystalline silicon solar cells

Abstract The effect of solid content of conductive silver paste on the film thickness, microstructure of screen-printed front contact, and electrical performance of crystalline silicon solar cells was investigated. Three different solid content pastes were tested. It is found that the solid content of silver paste strongly affects the film thickness, microstructure of the thick film, and electrical performance of the cells. The paste with 84 wt.% solid content has higher viscosity and density than the ones with 82 wt.% and 83 wt.%. After sintering, the front Ag electrode thick film prepared using the paste with 84 wt.% solid content has a larger film thickness and the corresponding cell exhibits higher photoelectric conversion efficiency than the ones with 82 wt.% and 83 wt.% under the same conditions. This indicates that increasing film thickness can improve the conversion efficiency.

Thermal Decomposition and Capacitive Properties of Carboxyl Ruthenium Oxide Thin Film

Carboxyl ruthenium oxide [RuO δ (OOCCH 3 ) λ ·nH 2 O] thin film has been prepared by in-situ decomposition using RuCl 3 ·3H 2 O isopropanol solution as precursor. Thermal decomposition and capacitive properties of the film have been investigated by Fourier transformation infrared spectroscopy, X-ray diffraction and electrochemical analyzer, respectively. Our results showed that RuO δ (OOCCH 3 ) λ ·nH 2 O thin film generated from RuCl 3 ·3H 2 O isopropanol solution below 300°C, and transformed into crystal RuO 2 at 400°C. Carboxyl played an important role on attenuation of specific capacitance of the film. Specific capacitance of the film reached 859 F g−1 and maintained at 99.7% of its original value after first two 8000 charge-discharge cycleswhen heat treated at 300 o C for 2 h.