Figure 5.

Nyquist plots (scattered) and their fitting results (line) of QDSCs with various counter electrodes under bias of Voc(under illumination of AM1.5). The inset (above) shows the detailed plots in the high-frequency region; (below) the equivalent circuit for the QDSC with the representation of impedance at CE/electrolyte interface (subscript CE), TiO2/CdS/CdSe/electrolyte interface (subscript 1) and series resistance (subscript s, including resistance in TiO2 film and electrolyte). The symbols R and CPE describe a resistance and a constant phase element, respectively; W accounts for finite-length Warburg diffusion

Deng et al. Nanoscale Research Letters 2010 5:986-990   doi:10.1007/s11671-010-9592-3