Up to now the topography of thick film silver paste metallization is still a great challenge to the crystalline silicon solar cell manufacturers due to lack of overall understanding about the dependence of screen-printed morphology on paste rheology. In this article, we demonstrate that both the shear thixotropy and wall slip are primary rheological behaviors of pastes affecting screen-printed morphology. By comparison among three different commercial pastes, the association of screen-printed morphology with apparent viscosity and slip velocity of pastes were investigated. The results from printing finger lines with designed width of 45 μm show clearly that the widening degree of lines is associated with the paste viscosity, and the height and cross-sectional profile of lines mainly rely on the wall slip velocity of paste passing through screen meshes. Briefly, the lower the apparent viscosity, the wider the lines; and the greater the wall slip velocity, the less the line height and more likely the formation of trapezoidal cross-sectional profile with larger area. Our study shows for the first time that the wall slip of pastes may produce significant influence on cell efficiency, since its influence on screen-printed morphology is considerably remarkable and vital.

•Avoiding use of phosphine contained solvent makes the preparation of the CdSe QDs green.•The absorption range of the QDs plays an important role in the cell's performance.•Cu2S is more suitable than Pt as the counter electrode.The CdSe quantum dots (QDs) were synthesized with ethanol and glycerol under 50–160 °C in the present work. The reaction temperature is lower than the traditional solvent thermal method to fabricate the CdSe QDs around 250–350 °C. What’s more, the avoiding of the use of phosphine contained solvent make the whole reaction environmental friendly. Then 3-Mercaptopropionic (MPA) was used to exchange the CdSe QDs’ ligand of olic acid. After that, the MPA-capped CdSe QDs were tethered onto the TiO2’s substrate, which guarantee the high coverage of the CdSe QDs on the TiO2 photoanode and the absorption range of 450–560 nm of light harvest. Furthermore, through the results of the CdSe QD’s size for the cells’ performance, we compared the significance of the QDs’ absorption range, the electron injection from the conduction band of CdSe QDs’ to TiO2’s and polysulfide to the valance band of the CdSe QDs in the cells’ performance and discuss the mechanism to improve the efficiency of the QDSCs. Finally, the QDSCs with polysulfide solution and Cu2S as counter electrode show excellent cell performance with open-circuit voltage (Voc) of 0.6 V, short-circuit current density (Jsc) of 10.58 mA/cm2, fill factor (FF) of 0.564, and PCE of 3.7%.

•A new kind of tellurite glass based on TeO2–B2O3–Bi2O3–PbO system is prepared.•B2O3 contributes most to increase the thermal stability of the glasses.•Bi2O3 is the most contributing oxide to decrease the thermal stability.•Increase of PbO content causes a decrease in Tg for the same heat treatment.•The variations of properties with the composition are discussed based on the FTIR.A new kind of tellurite glass based on TeO2–B2O3–Bi2O3–PbO system is prepared. It is found that B2O3 is the component that contributes most to increase the thermal stability of the glasses, while Bi2O3 is the most contributing oxide to decrease the thermal stability. The structural origins for the variations of the thermal stability with the glass composition are discussed based on the Fourier-transform infrared (FTIR) spectrometry measurement. The present glasses show potential to be used for photonic devices and low melting point sealing glasses.

Glasses with compositions (40 − x)PbO--xZnO--60(B2O3--SiO2) (x = 5, 10, 15, 20) have been prepared. Substitution of ZnO for PbO increased glass bandgap (Eg) and crystallization ability greatly. Crystalline phases of bulk glasses after rapid thermal processing (RTP) were identified by X-ray diffraction (XRD). Transmission line model (TLM) was employed to measure the electrical performance of Ag electrodes screen printed on polycrystalline Si substrates using Ag thick-film pastes and by RTP. The conductivity (σ) decreased while specific contact resistance (ρc) was not monotonic varied with increasing ZnO content. The correlation between electrical performance and glass barrier formed on the Ag gridline and Si emitter interface has been investigated.

Glass frit is critical for the Ag/Si contact formation and performances of Si solar cells. Lead–boron–silicate glasses were prepared through traditional melt-quenching method. The influences of softening temperature (Tf), as an important point of viscosity, on the Ag grid microstructures and performances of cells were discussed in detail. SEM images showed that Ag powders sintered well with decreasing Tf, resulting in improved performances of cells. The decreasing of Tf also affected the corrosion of SiNx coating, the amount and size of Ag re-crystallites, and glass layer thickness between Ag gridline bulk and Si emitter surface. Therefore, glass frit Tf is the key factor for optimizing performances of cells.

Spherical silver particles used in electronic paste for solar cell were prepared using the chemical reduction method with ammonia as a complex agent, hydrazine hydrate as a reducing agent, and gelatin as a protective agent. The gelatin protective mechanism in the preparing process of spherical silver particles was studied. Observations of SEM and results of laser particle size analysis and ultraviolet absorption spectra demonstrate the formation of the coordinative complex of silver ions with gelatin in aqueous solution which accelerated the reduction of silver ions. Moreover, gelatin can promote the nucleation of the metallic silver particles, thus beneficiating availability of the monodisperse spherical silver particles.