Response function 126 Solar cell

FIG. 61. Solar cell performance parameters as functions of power density for cells made at 65 MHz (a) yjc, efficiency, Vqc- and fill factor (FF) (b) spectral response. 

Photovoltaic performance of the DSSC is described as follows Figure 8 shows the external spectral response curve of the photocurrent for nanocrystalline Ti02 solar cells sensitized by N3 and black dyes with the I /If redox mediator, where the incident photon-to-current conversion efficiency (IPCE) is represented as a function of wavelength. IPCE is obtained by the following equation ... 

Figure 8 Spectral responses (IPCE) of N3- and black dye-sensitized 2 solar cells. IPCE is plotted as a function of wavelength. (Data from Ref. 20.)...

Transient electrical data collected under different bias conditions contain enough information to determine the density of states with the aid of a transient device model. One study has shown that by simultaneously fitting a number of transient current measurements, as well as steady-state device response, a non-trivial best fit for the densities of sub gap electron and hole states could be obtained [86]. In a further application of the transient device simulation it has been shown that in certain conditions the transient current extracted from a solar cell device accurately reflects the density of states of the carrier type with the greater density of deep trap states [160]. In those conditions where this approximation is true, then transient current data can be modelled with a simple expression for current due to thermally emitted charge carriers, and the current transient mapped onto a density of states function [51, 52]. However, the approximation fails in the limit of significant recombination or low electric fields. 

A transient (time-of-flight) approach was used to find the diffusion coefficient of ferrocenium (Fc+) in a nanostructured Ti02 film in a dye-sensitized solar cell (DSSC) configuration. By measuring the tip response for Fc+ reduction (where Fc+ is produced by the photoreaction) as a function of tip-substrate distance, the Z)-value within the film could be determined. A steady-state measurement was used to measure the rate constant for the oxidation of F by the oxidized dye under irradiation with ZnO/eosin Y - or ZnO/dye D149 DSSCs. °... 

---