Wrinkled Titanium Nitride Nanocomposite for Robust Bendable electrodes.
Electrical contacts and interconnects are critical component for all electronic devices. Standard electrode and contact are metallic, OSC and OLED generally use doped metal oxides as transparent electrodes. Indium tin oxide (ITO) is well a known transparent oxide because it exhibits high optical transmittance about 90 % in the visible region and very low sheet resistance. However, mosts of these materials are not compatible with flexible substrates, being extremely brittle. Bendable electrodes with enhanced electro-mechanical properties are higly desirable to develop innovative wearable electronic devices. At UC, we developed a fabrication method for highly bendable coatings based on Titanium nitride (TiN) and Silver Nanowires (Ag NWs). TiN and TiN-AgNWs nanocomposites were deposited onto flexible organic substrates using a Plasma Enhanced Pulsed Laser Deposition (PE-PLD) technique. We show that the coating sheet resistance can be tuned using a dual frequency PLD process and further decreased by incorporating Ag NWs in TiN layer, down to value as low as RS = 3.5 Ω per square. Moreover,thick TiN/PET coatings ( tf >100nm) exhibit micro-structural changes that greatly improve their fracture and delamination resistance. The electro-mechanical robustness of TiN based coatings were evaluated by four-probe resistance measurements in situ under cyclic bending tests.The data demonstrate that these coatings exhibit robust electro-mechanical properties that surpass commercial ITO/PET substrates.