A novel CdTe ink-assisted direct synthesis of CdTe thin films for the solution-processed CdTe solar cells

Abstract

The CdTe ink in thiol-amine cosolvents from CdTe powder has been successfully prepared via Triton X-100 surfactant at 50 °C. The CdTe thin films have been synthesized and characterized from the prepared CdTe ink using spin coating method. The SEM micrographs reveal that synthesized films are uniform, smooth and homogeneous with less cracks, voids and pinholes compared to the films deposited from the inks without surfactant. The XRD spectra confirm the mixed hexagonal and cubic structure of the deposited films. The Raman peaks at 142 and 122 cm−1 indicate the CdTe and the pure Te phase, respectively. The FTIR peaks at 1638 and 1384 cm−1 due to C=O and COO- groups originated for the stretching vibration of the ligands of the thiol-capped CdTe, and the absence of vibrational peaks of S–H in the range of 2550–2650 cm−1 confirms the thiol-capped CdTe, respectively. The EDX results reveal the existence of Cd and Te elements in CdTe films. The deposited films exhibit the highest absorbance (~85%) with a band gap of 1.5 eV. Hall studies and electrical analysis indicate the high quality of the CdTe films. Therefore, it can be concluded that the developed surfactant-mediated CdTe ink is highly promising for solution-processed CdTe-based photovoltaics.