Page 194 - Organic Electronics in Sensors and Biotechnology

Progress and Challenges in OLED-Based Chemical and Biological Sensors 171

14
12

10
8
τ 0 /τ
6
4

2

0
0 10 20 30 40
DO concentration (wt. ppm)

FIGURE 5.2 Calibration line for a PtOEP-based DO sensor at 23°C.

25

20

τ 0 /τ 15

10

5

0
0 2 4 6 8 10 12
DO concentration (wt. ppm)
FIGURE 5.3 Calibration line for a PdOEP-based DO sensor at 23°C.

Deviations of SV plots from linearity are common, as shown in
Figs. 5.4 and 5.5, which show such plots of PtOEP- and PdOEP-based
gas-phase sensors. Changing the preparation conditions of the sens-
ing film can affect the linearity of the SV plot.
For the results shown in Fig. 5.4, the [Alq OLED]/[PtOEP:PS] sen-
3
sor module was turned on once every 24 h, and τ was determined vs.
the O level, which varied from 0 to 100%. In this pulsed mode, the
2