Page 184 - Organic Electronics in Sensors and Biotechnology

Integrated Pyr oelectric Sensors 161

PVDF-sensor (25 μm foil) + OTFT (Al O 3 , Pentacene)
2
= –0.5 V, V = –3 V, R = 1 GOhm, Square (0.1 Hz)
V G D G
1.E–06
1.E–07

I Drain (A) 1.E–08

1.E–09

1.E–10
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Time (s)

PVDF-sensor (25 μm foil) + OTFT (Al O , Pentacene)
3
2
V = 0 V, V = –3 V, R = 1 GOhm, Sinus (0.1 Hz)
G
G
D
1.E–07
1.E–08
I Drain (A) 1.E–09

1.E–10

1.E–11
0 500 1000 1500 2000 2500 3000
Time (s)

FIGURE 4.30 Top: Drain current modulations of an OTFT at V =−3 V and V =−0.5 V
D G
connected to a PVDF-foil capacitance induced by an intensity-modulated laser diode
(square waveform). Bottom: Long-term behavior of the I modulation for an
D
integrated PVDF-sensor solely controlled by intensity-modulated laser diode (square
waveform, V =−3 V and V =−0 V).
D G

the fact that the input impedance of the OTFT is of the order of
150 MΩ, which is significantly smaller than that of the parametric
analyzer (1 GΩ).
If no voltage is applied from the analyzer sources, the OTFT is
driven solely by the output voltage of the foil sensor element. In