Figure 7

Representative J - V curves for mesoporous ZnO samples synthesized using different concentrations of NaOH. The concentrations used were 0.15 M (sample A), 0.2 M (sample B), 0.25 M (sample C), 0.3 M (sample D), 0.35 M (sample E), 0.4 M (sample F), 0.45 M (sample G), and 0.5 M (sample H). The samples were calcinated at 315°C for 12 h.