Figure 1

SPV of porous-ZnO, CuPc and porous-ZnO modified with CuPc at different ratios (a). PCB77 responses of the SPV-based sensors built from porous-ZnO:1% CuPc (b) and porous-ZnO (c). The straight solid lines are linear fit (b–c). (Insets: PCB77 responses in the linear concentration scales).