Development of Indium-Tin Oxide Thin Films on PAMAM Dendrimer Layers for Perovskite Solar Cells Application

Despite the dramatic progress that has been made in the power-conversion efficiency (PCE) of perovskite solar cells (PVSCs), there are still many obstacles to be overcome before these devices can be economically competitive in the photovoltaics market. One of the major hurdles in the commercialization of PVSCs is low stability, which severely limits the effective lifetime of the devices. One of the approaches to achieving higher stability and lifetime of PVSCs is improvement of PVSC film quality. In this paper, we have employed a PAMAM dendrimer layer to reduce the surface roughness of sputter-deposited indium-tin oxide (ITO) films, which were then used in the fabrication of PVSCs. A PAMAM-8 dendrimer layer was deposited by dip-coating the substrates in 25 mL of a 1 μM PAMAM-8 ethanol solution before ITO deposition. X-ray refractivity (XRR) was used to verify the PAMAM layer on the substrate. ITO films of 150 nm thickness were then deposited onto the PAMAM layer using DC magnetron reactive sputtering. The surface roughness, sheet resistance, and transmissivity of the ITO films were optimized by varying the parameters of the sputtering process. Atomic force microscopy (AFM) was used to measure the surface roughness of the ITO films with and without PAMAM dendrimer layer. A root-mean-square (RMS) film roughness of 1.6 nm, sheet resistance of 21 Ω/Υ, and transmissivity of > 91% at a wavelength of 400–700 nm were obtained after optimization.