Photocurrent-photovoltage characteristics

Figure 1. Photocurrent-photovoltage characteristics of the cell n-Si (Pt silicide coated)/1.0 M FeClg, 0.1 M FeCU, 1 M HCl/Pt at 65 nW/cm2 illumination. Pt thickness deposited 40 A and annealing temperature 400 °C at 10 6 torr for 10 min. Key a, before long-term stability test and b, after long-term stability test.

Figure 23 Photocurrent-photovoltage characteristic of the ceU Pt (H2)/0.5 M H2SO4//O.5 M H2SO4/ p-BP irradiation with 500 xenon lamp. (From Ref. 75.)...

Despite the potential impact of novel photosynthetic routes based on these developments, the most ambitious application remains in the conversion of solar energy into electricity. Dvorak et al. showed that photocurrent as well as photopotential response can be developed across liquid-liquid junctions during photoinduced ET reactions [157,158]. The first analysis of the output power of a porphyrin-sensitized water-DCE interface has been recently reported [87]. Characteristic photocurrent-photovoltage curves for this junction connected in series to an external load are displayed in Fig. 22. It should be mentioned that negligible photoresponses are observed when only the platinum counterelectrodes are illuminated. Considering irradiation AM 1, solar energy conversions from 0.01 to 0.1% have been estimated, with fill factors around 0.4. The low conversion... 

In the steady state the left-hand side of Eq. (13) is equal to 0. Measurables are the steady state photocurrent, photovoltage, light and dark current voltage characteristics, and the quantum efficiency spectrum (or IPCE). If the physical origin of in is known, the dependence of such DC measurements on variations in intensity, wavelength, and bias, deliver the parameters controlling (for example, the values of the diffusion length and diffusion constant in the case of diffusion limited transport). 

The efficiency of such cells is characterized by its photocurrent photovoltage correlations which are obtained if the two electrodes are connected via an external resistance. This gives the so-called power characteristics for which Fig. IV.3 gives three examples. The conversion efficiencies for solar light of these systems... 

Figure 15.2 Typically observed voltage-current characteristic curve for PEC ceii. Js(> a short-circuit photocurrent Voc- a open circuit photovoltage FF fill factor, tj conversion efficiency Wmax a maximum output.

Before describing particular systems of PEC cells, let us formulate their main quantitative operating characteristics. The cell efiBciency ti is the ratio of the electric output power to the luminous input power, Pp The former is a product of photocurrent and photovoltage, Ip. Vph, and reaches its maximum value at a certain load resistance, R. Thus,... 

BLM effecting reduction and oxidation, respectively. The characteristics of the action spectra (either photovoltage or photocurrent) are determined by its action [1-3, 15-19, 25, 26, 41],... 

Fig. 4.85. (a) Current-voltage characteristics of a dark and an illuminated diode (b) photovoltage at the open ends and photocurrent in a shortened diode as a function of incident radiation power... 

The power characteristics of a photocell can be constructed from the individual current voltage curves of the photoelectrode and the counter electrode. This is shown in Fig. IV.4, again for an n-type semiconductor. In this figure the influence of the counter electrode is indicated. If the redox reaction there is slow, i.e. if it needs large overvoltages, the power characteristics are very much worsened. A similar effect has the photoelectrode if the photocurrent does not increase very steeply below the open circuit photovoltage and does not reach the saturation current very soon. 

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