The calculated hole concentrations and hole photocurrents as a function of light intensity for the range of 5.79×10 -5 ~5.79×10 2 mW•cm -2 are shown in Figure (a). The hole concentrations are in units of h + nm -2 , as has been conventionally done in prior studies. Here, nm 2 refers to sample geometric surface area, and includes the holes formed as a function of light absorption depth in the underlying crystal. In both Model 1 and Model 2 the hole photocurrent increases with increasing light intensity and then reaches saturation. The hole photocurrent generated by Model 2 is significantly larger than that of Model 1, reaching a value 30 times higher at 100 mW•cm -2 and above. This is because model 1 does not require the two species that are going to react together to be right next to each other, while model 2 does. We are comparing two extreme cases here, and the real situation is somewhere in between. Figure (a) shows that the total hole concentrations in the bulk crystal above about 1mW•cm -2 are the same under both models. and continue to increase as the light intensity increases without reaching saturation.