Methods
Cyclic voltammetric method was used for the electrodeposion of
Prussian blue on ITO electrode. The scanning range was set
between -
0.2 V and 1.2 V with a scan rate of 0.05 V/s. Before use,
the ITO electrode was ultrasonicated in ultrapure water for 5 min,
and then it was ultrasonicated in ethanol for 5 min. The electro-
deposition experiment was conducted with a freshly prepared so-
lution containing 5.0 mmol/L FeCl3, 5.0 mmol/L K3Fe (CN) 6, and
10 mmol/L HCl. After scanning for 10 cycles, a desirable PB film was
obtained on the ITO plate. The fingerprint collection experiments
were conducted in a fume cupboard, where the relative humidity
and temperature were monitored and controlled. When the ITO
plate was connected to an electric power of an appropriate voltage,
the fingerprint images can be obtained by rolling the finger on the
ITO film.