Paper PS1-TuA7
Defect Analysis and Mechanical Performance of Optoelectronic Thin Films Deposited on Flexible Substrates

Tuesday, October 30, 2012, 4:00 pm, Room 24

Plasma deposition enables synthesis of optoelectronic thin films on flexible substrates at low temperature. The ultimate performance of these materials is controlled by defects such as pinholes or cracks. This work focuses on understanding the formation of such defects during both film synthesis as well as during the application of stress. A simple solvent-etch based technique is presented which can be used to visualize and quantify defects in both single and multi-layered films deposited on flexible substrates. This approach allows for quantitative evaluation of crack/defect density evolution. This technique is applied to both sputtered indium tin oxide (ITO) as well as alumina-silicone nanolaminates deposited on flexible polycarbonate films by plasma-enhanced chemical vapor deposition. The use of the nanolaminate architecture is shown to significantly attenuate pinhole density relative to single layers. In the case of sputtered ITO, an optimum thickness is identified that balances electronic performance with mechanical integrity. For both materials their performance under applied stress was examined using an automated bending test setup that explored mechanical failure as a function of applied strain and number bending cycles. The threshold strain for failure under the application of tensile/compressive stress was quantified by bending samples to a given radius of curvature. Below a critical strain these materials demonstrate robust performance during cycling, displaying their strong potential for device applications.