CIS layer deposition through electrospray process for solar cell fabrication

A rather new technique for the deposition of CIS layer has been discussed in this paper namely Electrospray Deposition (ESD). Thin films composed of Copper–Indium–diSelenide, have been achieved using the ESD technique for the ultimate manufacture of CIS based solar cell. CIS nano-particle inks are used in the ESD process for the deposition of ∼2 μm CIS layers on ITO coated substrates whereby ITO coating can be used as the back contact of the solar cell. Different parameters affecting the ESD process and the deposited layer thickness and uniformity such as stand-off distance, flow rate and voltage have been examined as well to come up with an optimized parameter combination. Layers with fine uniformity are achieved at two different substrate speeds, 0.5 mm/s and 1.0 mm/s. The thickness of the deposited films varied from 400 nm to 2.7 μm with varying flow rate from 30 μl/h to 230 μl/h and 2.8 μm–1.3 μm with varying stand-off distance from 13 mm to 6 mm. The cost-effectiveness, room-temperature operation, environment friendliness and simplicity of ESD process with its possible integration with high throughput manufacturing processes like Roll-to-Roll process makes it an idyllic candidate for deployment in the solar cell fabrication process at a large scale.

► Thin films of Copper-Indium-diSelenide have been deposited through Electrospray process.
► CIS nano-particle colloidal ink is used in the process to form CIS layers in a single step at room conditions.
► Layer morphology has been analyzed by SEM and AFM analysis that confirm fine layer characteristics.
► Effect of the flow-rate and stand-off distance on layer morphology and thickness has been analyzed.
► The layer thickness ranged from 400 nano-meters to 2.7 micro-meters depending upon these parameters.