Investigation On The Sintering Behavior And Sintering Mechanism Of Ag Nanospheres/Ag Nanoplates Hybrid Conductive Ink

In recent years,the electronic devices are developing to flexible,lightweight and functional direction.The substrate for flexible printing electronic technology like paper,plastic and textile has been widespread.In this paper,with the aim of developing highly conductive ink for flexible electronics on heat-sensitive substrates,Ag nanospheres and nanoplates were mixed to synthesize hybrid inks.Five kinds of hybrid ink and two types of pure ink were written to square shape on Epson photo paper using rollerball pens and sintered by two different ways.The first sintering method is thermal sintering.In this work,the films were sintered at a low temperature(100?)for only 30 minutes to avoid bringing damages to the heatsensitive substrate.The microstructure,electrical resistivity,surface porosity,hardness and flexibility of silver patterns were systematically investigated and compared,as well as the sintering mechanism.It was observed that the optimal mixing ratio of nanospheres and nanoplates was 1:1,which equipped the directly written pattern with excellent electrical and mechanical properties.The electrical resistivity was 0.103 ??·m,which was only 6.5 times of bulk silver.The enhancement compared to pure silver nanospheres or nanoplates based ink was owing to the combined action of nanospheres and nanoplates.It was a valued way to prepare Ag nanoink with good performance for printed/written electronics.The second sintering method is chemical sintering at room temperature.Films were immersed in the NaCl solution in order to detach the organic layer from the surfaces of Ag nanoparticles and achieve the spontaneous coalescence of Ag NPs.To obtain the optimal sintering parameters,films were sintered at different concentrations for different time.It was found that the film exhibited the best conductivity when the mixing ratio was 1 to 1 with sintering concentration at 1 mol/L and sintering time for 30 min.SEM images were analyzed to compare the microstructures.TEM,FT-IR and XPS analysis were conducted to explore the sintering mechanism.The ink stability was also investigated.