Electrostatic InkJet Printed Silver Grids for Non-vacuum Processed CIGS Solar Cells

Printed electronics (PE) technology shows huge promise for the realisation of low-cost flexible electronics. Here, we demonstrate the use of Electro-Static Inkjet (ESJET) printing technology to deposit silver nanoparticle (Ag nps) inks for fabrication of grid electrodes for non-vacuum processed Cu(In,Ga)S2 (CIGS) solar cells to bridge the gap of additive printing between high viscosity screen printed materials and low viscosity inkjet processes. The effect of printing parameters and the sintering condition of the ESJET printed Ag grids were investigated by the measurement of photovoltaic performance parameters of CIGS solar cells. It was found that sintering temperatures of 220°C caused a significant loss of performance in the CIGS cell however, sintering of the Ag grids at temperatures up to 160°C produced a cells with good performance and efficiency comparable to the test cells using thermal evaporated Ag grids. Results from stability test (ISOS-D-1) shows the efficiency of the CIGS solar cells with ESJET printed Ag grids decreased from 11.14% to 10.44%, which is around 0.6% efficiency after 3 months in air without any encapsulation. ESJET printing is a viable method for production of PV metal grids which can minimize material waste and enable significant cost reduction of thin film solar cells.