Solar cells energy conversion efficiencies

As reported [49] and as shown in Fig. 9, the cell generates a light variation insensitive potential of 1.2-1.3 V at total (including storage losses) solar-electrical energy conversion efficiency of over 18%. 

It has been illustrated that polycrystalline materials can be operated in regenerative electrolytic solar cells yielding substantial fractions of the respectable energy conversion efficiency obtained by using single crystals. Pressure-sintered electrodes of CdSe subsequently doped with Cd vapor have presented solar conversion efficiencies approaching 3/4 of those exhibited by single-crystal CdSe electrodes in alkaline polysulfide PEC [84]. 

By using a multichamber system [129], exchange of residual gases between successive depositions will be strongly decreased, and very sharp interfaces can be made. Furthermore, the use of a load-lock system ensures high quality of the background vacuum, and thus low levels of contaminants in the bulk layers. Multichamber reactor systems have been used for the fabrication of solar cells, and considerable improvements in energy conversion efficiency have been achieved [130, 131]. 

Z. S. Wang, H. Kawauchi, T. Kashima, H. Arakawa. Significance influence of Ti02 photoelectrode on the energy conversion efficiency N719 dye-sensitized solar cell. Coord Chem Rev 248 1381-89... 

Graphene has also been studied as the acceptor within the active layer of the cell (see Fig. 35). In these studies hydrophilic GO and solution-processable functionalized graphene (SPFGraphene) act as efficient acceptor moieties [272, 280]. In these cells it has been determined that the energy conversion efficiency depends on the graphene content and the annealing temperature of the cell when constructed (see Fig. 36). Conversion efficiencies vary from 0.034 to 1.4% for SPFGraphene [280] and from 2.1 to 3.8% for GO based solar devices [277]. 

Scharber MC, Wuhlbacher D, Koppe M, Denk P, Waldauf C, Heeger AJ, Brabec CL (2006) Design rules for donors in bulk-heterojunction solar cells - towards 10% energy-conversion efficiency. Adv Mater 18 789... 

High solar-energy conversion efficiency. A high efficiency equal to that of the amorphous Si solar cell has been obtained as a laboratory development and efficiencies greater than 10% might be possible. 

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