Solar to-electrical conversion efficiency

Chang KC, HeUer A, Schwartz B, Menezes S, Miller B (1977) Stable semiconductor liquid junction ceU with 9 percent solar-to-electrical conversion efficiency. Science 196 1097-1099... 

In order to get an estimate of the solar-to-electrical conversion efficiency on layered compounds, sample D has been measured in sunlight. The result, obtained at 92.5mW/cm2 insolation is shown in Fig. 8. The maximum power point is at 0.33V and 10.7mA/cm2, with a resulting solar conversion efficiency of 3.7%. As is evident from Fig. 7, some samples show better overall performance than sample D. The best of these, sample G, the surface of which was accidentally damaged before being measured in the sun, had a maximum power output which exceeded that of sample D by a factor of 1.4 bringing the estimated solar conversion efficiency to 5.2%. 

Chemisorption of a fraction of a monolayer of Ru33 also improves the performance of n-GaAs based solar cells. The solar-to-electrical conversion efficiency of a... 

Figure 10.8 Potentiostatic photocurrent-voltage characteristics for an illuminated n-CdSeo.65Teo.35 single crystal immersed in either of two types of aqueous polysulphide electrolyte. The top curve is for 1.8 M CS2S and 3 M sulphur bottom curve is for 1 M NaOH, 1 M Na2S, 1 M sulphur. The photocurrent-voltage curves were obtained outdoors in sunny conditions and solar-to-electrical conversion efficiencies are indicated.

K. C. Chang, A. Heller, B. Schwartz, S. Menezes, and B. Miller, Stable semiconductor liquid-junction cell with 9% solar to electrical conversion efficiency, Science 196 (1977) 1097-1098. 

Based on the processing of InP(lll) A, described in Section 2.4.2.1, a stable pho-toelectrochemical solar cell has been developed. Adler the aforementioned cyclic polarization in HCl, an additional cycHc conditioning in V /HC1 redox electrolyte was performed. This treatment resulted in a further increase of the fill factor as shown in Figure 2.80. The solar-to-electrical conversion efficiency, measured in natural sunlight, was 11.6% in a two-electrode configuration and the result is shown in Figure 2.81. 

The photoelectrochemical solar cell is completed by using an acidic 12/1 electrolyte as redox couple with a carbon counter electrode and calomel reference electrode. The solar-to-electrical conversion efficiency characteristic is shown in Figure 2.89. Upon illumination with a W-I lamp, an efficiency of 11.2% is reached. 

Examples of chronological improvements in high solar to electrical conversion efficiency PEC s are summarized in... 

The multiple band gap solar to electrical conversion efficiency of 19.2% compares favorably to the maximum 15 to 16% solar to electrical energy conversion efficiency previously reported for single band gap PECs [9, 10]. Small photoelectrochemical efficiency losses can be attributed to polarization losses accumulating at the solution interfaces. Under illumination, a photocurrent density of 13 mA cm seen in Fig. 7 is consistent with polarization... 

The Fig. 12 inset contains the Eq. (18)-determined ]electrolysis- The limiting maximum photoelectrolysis can be readily determined from the solar to electrical conversion efficiency. Expanding Eq. (15) with Eq. (18), photoelectrolysis is diminished from Tjphoto l y the potential of the stored energy compared to the potential at which the water electrolysis occurred ... 

In 1976, the first regenerative PECs with substantial and sustained solar to electrical conversion efficiency were demonstrated. These PECs are based on n-type cadmium chalcogenide (S, Se or Te) electrodes immersed in aqueous polychalcogenide electrolytes. The cells were introduced by Hodes, Cahen, and Manassen (31), Wrighton and coworkers [32], and Heller and Miller [33] and were capable of converting up to 7% of insolation to electrical energy. Most investigations of these systems focused on solid-state and interfacial aspects of these PECs and photodriven oxidation of polysulfide at the photoelectrode was represented ... 

Parkinson, Heller, and Miller [58] and Lewis and coworkers [59] have shown that metal ion (Ru +, Os +) treatment of the -GaAs surface leads to high solar to electrical conversion efficiencies in these cells... 

Along with conventional parameters constraining photovoltaic devices, modification of the electrolyte (solution phase) chemistry is a key to understanding the mechanism of energy conversion and device characteristics of PECs. The fundamental importance of modification of the electrolyte in terms of the distribution of species in photoelectrolytes and the pragmatic importance in terms of enhanced solar to electrical conversion efficiency is reiterated by studies... 

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