Optical, electrical and electrochemical properties of PCL5/ITO transparent conductive films deposited by spin-coating ‒ Materials for single-layer devices

In this paper, we report on the synthesis of solid polymer electrolytes (SPEs) on the basis of 95 wt.% PEO and 5 wt.% of anhydrous cobalt (II) chloride hexahydrate (CoCl2·6H2O), hereafter called PCL5, by the spin-coating technique using different types of glass (normal, quartz, ITO) substrates. The PCL5 electrolyte exhibits the highest conductivity and the lowest optical bandgap and hence, it was selected as a component to fabricate the organic single-layer device. The XRD measurements show that thin films have an amorphous structure after adding 5 wt.% of dopant. The IT5 (PCL5/ITO/glass) is transparent, the index of refraction is 1.359 at 450 nm, the maximum conductivity is 1.21 × 10−3 S cm−1 at 343 K and this material exhibits an energy bandgap of 3.47 eV. The electrochemical behavior and the stability of the device were examined with the help of cyclic voltammograms (CV). Linear sweep voltammetry (LSV) reveals that, as also found in the cathodic cycles, the electrolyte stability window of IT5 was 1.25 V. Accordingly the IT5 film can be considered as a transparent conductor potentially applicable for various optoelectronic devices.