Figure 2: Voltage outputs and sensitivity of the sensor devices.

Effect of (a) sound wave frequency, (b) SPL (sound wave frequency, 220 Hz), (c) hole profile on device voltage outputs. Effect of (d) hole diameter (web thickness, 40 μm; sound wave frequency, 220 Hz; SPL, 115 dB), (e) thickness of the nanofibre web (hole diameter, 12.8 mm; sound wave frequency, 220 Hz; SPL, 115 dB), (f) nanofibre web area (hole diameter, 12.8 mm; web thickness, 40 μm; sound wave frequency, 220 Hz; SPL, 115 dB) on device sensitivity. The error bars represent the s.d. of the test results of at least three replicates.