(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂-Based Nanomaterials

Figure 3

Schematic energy model of the n-type semiconductor/electrolyte interface before (a) and after (b) the establishment of equilibrium. The presence of surface states in the semiconductor is neglected. 𝐷_red and 𝐷_ox correspond to the distribution functions of the density of states for reduced and oxidized species, respectively, of the redox system (the energy distribution of reduced and oxidized species is different due to different solvation; 𝜆 is the reorganization energy). Φ, 𝜒, and IE are the work function, electron affinity, and ionization energy, respectively, of the semiconductor (index _S) and of the electrolyte (index _E).