Study of conducting ITO thin film deposition on flexible polyimide substrate using spray pyrolysis

Rachita Rana,M Nasim,J Chakraborty,Santosh K Tripathi

doi:10.1007/s40097-015-0177-7

Abstract

Nanostructured indium tin oxide (ITO) thin films have been grown by chemical spray pyrolysis method on flexible polyimide (PI) polymeric substrates at various temperatures (400, 450 and 500 °C) using solutions of indium and tin chlorides as precursors. The composition, microstructure, surface morphology, thermal, electrical, and optical characteristics have been analysed by FT-IR, UV–Vis, X-ray diffraction, SEM, EDAX, atomic force microscopy, electrical measurements, TGA, etc. X-ray diffraction measurements employing Cu-Kα radiation showed that the ITO films were polycrystalline with a cubic bixbyite structure. An increment in average grain size, electrical conductivity and optical transmittance was observed at higher substrate temperature. ITO-coated films maintained the mechanical properties and stability of the pristine PI films. The adhesion between surface ITO layers and PI matrix was found acceptable.

Highlights

The deposition of conducting metal oxides on various substrates, on polymeric surfaces [1,2,3] has been gathering great attention due to its potential applications in the field of flexible micro-electronics, circuit board optics, sensors, outer space materials, solar cells, wearable displays, aerospace and surface conductive flexible polyimide tapes [4,5,6]
We have investigated only the effect of the substrate temperature on the growth of the indium tin oxide (ITO) film keeping other factors constant
Conducting metal oxide, ITO films were deposited by chemical spray pyrolysis on Pyromellitic dianhydride (PMDA)-ODA PI substrates at different temperatures to study the effect of substrate temperature on the physical, optical and electronic properties of the film

Summary

Introduction

The deposition of conducting metal oxides on various substrates, on polymeric surfaces [1,2,3] has been gathering great attention due to its potential applications in the field of flexible micro-electronics, circuit board optics, sensors, outer space materials, solar cells, wearable displays, aerospace and surface conductive flexible polyimide tapes [4,5,6]. Out of the varieties of polymeric materials available, polyimides are well known to show the most promising blend of the thermal and the mechanical properties [8]; they possess thermal stability, good filmforming ability, low dielectric constant [9], high chemical resistance, low coefficient of thermal expansion and high. Polyimides are used as highperformance engineering plastics and are considered well applicable for high-performance material [14]. Due to these reasons polyimides are largely used as matrix for various purposes and the advantages of polyimide have been exploited as substrate to deposit transparent conducting oxide (TCO) film over it. It is worthy to mention here that an improved version of the pyrolysis technique is the socalled pyrosol or nebulized spray pyrolysis, which uses the transport by a carrier gas and the subsequent pyrolysis of a spray generated by an ultrasonic atomizer [21]

Methods

Results

Conclusion