Flexible graphene-based micro-capacitors using ultrafast laser ablation

This study investigated the sensor performance and durability of flexible graphene-based micro-capacitor using ultrafast laser ablation with picosecond (PS) pulses. Micro-patterns were fabricated under varying electrode widths, lengths, and gaps on the flexible polyethylene terephthalate (PET) substrates for optimal capacitive performance. The experimental results showed that the untouched capacitance of the micro-capacitors had an approximately linear relationship with electrode widths and lengths. Increasing the electrode width can effectively enhance capacitance of the micro-capacitor, especially under small electrode gap. Micro-capacitors exhibited stable relative resistance change and excellent capacitance retention when bending angle θ ≤ 30° after 1000 times bending test. The decreasing rates of capacitance retention substantially increased with bending angles from 30° to 180°. Touched capacitances increased sharply as pressure rose from 0 to 6 kPa. These experimental results can be considered in designs of durable and high sensitivity flexible graphene-based touch sensors.