CuI-TiO2 Composite Thin Film for Flexible Electronic Applications

Copper iodide (CuI) is a p-type transparent conductor that can be synthesized and doped at low temperature (≤ 100 °C) while maintaining its high-conductivity and high optical transmittance (> 75 %). The realization of such simultaneously high conductivity and transparency makes CuI useful for applications in both active and passive flexible electronics. However, a few of the major disadvantages of CuI include its optical and electronic stability at ambient atmosphere and reduced transparency with iodine doping. In this report, instead of using pure CuI, we fabricate CuI-TiO ₂ composite thin films which are highly transparent and stable at ambient conditions whilst maintaining degenerate p-type conductivity. The CuI-TiO ₂ composite film is >80 % transparent (450- 2000 nm range), highly conducting ( _~ 77 S/cm), heavily doped (> 1.2 × 10 ²⁰ /cm ³ ), with a mobility of _~ 3.5 cm ² V ^-1 s ^-1 .