ABSTRACT
An epoxy-based solder paste (ESP) is a promising alternative to conventional solder pastes to improve the reliability of fine-pitch electrical joining because the epoxy encapsulates the solder joint. However, development of an appropriate epoxy formulation and investigation of its reaction mechanism with solder powder is challenging. In this study, we demonstrate a newly designed ESP consisting of diglycidyl ether of bisphenol F (DGEBF) resin, Sn-3.0 Ag-0.5 Cu (SAC305) solder powder, and L-glutamic acid (Glu), which is a proteinogenic amino acid for biosynthesis of proteins in living systems. The mechanism of the thermochemical reaction was explored and tentatively proposed, which reveals that the products of the reaction between SAC305 and Glu function as catalysts for the etherification of epoxides and alcohols produced by chemical bonding between DGEBF and Glu, consequently leading to highly crosslinked polymeric networks and an enhancement of impact resistance. Our findings provide further insight into the mechanism of the reaction between various formulations comprising an epoxy, amino acid, and solder powder, and their potential use as ESPs for electrical joining.
ABSTRACT
A cost-effective structure for dye-sensitized solar cells (DSSCs) without using transparent conductive oxide (TCO) is reported. Instead of high-cost F/SnO(2) glass (FTO-glass) or woven metal mesh, a Ti foil and a perforation-patterned stainless steel (StSt) foil are introduced as the substrates for a counter-electrode and a photo-electrode, respectively.
ABSTRACT
A novel ionic siloxane hybrid electrolyte was fabricated by thermal polymerization of iodide-oligosiloxane resin. The nanosized iodide-oligosiloxane was synthesized by a simple sol-gel condensation of 3-iodopropyltrimethoxysilane and diphenylsilanediol. It is found that the composition and concentration of the oligosiloxane used in the electrolyte affect the performance of the dye-sensitized solar cells (DSSCs). An optimized DSSC with the hybrid electrolyte using smaller molecular-sized oligosiloxane with a greater amount of iodide groups presented solar to electricity conversion efficiency of 5.2% at 1 sunlight (100 mW cm(-2)), which is comparable to that afforded by a liquid electrolyte.
