Photovoltaic performance

Ahrenkiel, R. K. 1989. The effect of deep states on the photovoltaic performance of CdZnS/CuInSe2 thin film devices. Solar Cells 16 549-565. 

Menzies, D. B. Dai, Q. Bourgeois, L. Caruso, R. A. Cheng, Y. B. Simon, G. P. Spiccia, L. 2007. Modification of mesoporous Ti02 electrodes by surface treatment with titanium(IV), indium(III) and zirconium(IV) oxide precursors Preparation, characterization and photovoltaic performance in dye-sensitized nanocrystalline solar cells. Nanotechnology 18 125608. 

Scientific interest in nanocarbon hybrid materials to enhance the properties of photocatalysts and photoactive electrodes has been growing rapidly [1-8]. The worldwide effort to find new efficient and sustainable solutions to use renewable energy sources has pushed the need to develop new and/or improved materials able to capture and convert solar energy, for example in advanced dye-sensitized solar cells - DSSC (where the need to improve the photovoltaic performance has caused interest in using nanocarbons for a better cell design [9,10]) or in advanced cells for producing solar fuels [11-13]. 

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 ... 

We usually prepare an unsealed DSSC and measure its photovoltaic performance. A spacer film, such as polyethylene (15-30 pm thickness), is placed on the dye-coated 2 photoelectrode and then the electrolyte solution is dropped on the surface of the Ti02 photoelectrode using a pipette (one or two drops). The counterelectrode is placed over the 2 photoelectrode and then the two electrodes are clipped together with two binder clips. If a low-melting-point polymer film such... 

Table 1 Photovoltaic Performance of N3 or N719 Dye-Sensitized TiCb Solar Cells...

Table 2 Photovoltaic Performance of Dye-Sensitized Ti02 Solar Cells Prepared at PCRC/AIST...

Table 3 Photovoltaic Performance of DSSC Using Different Oxide Semiconductor Photoelectrode...

Photovoltaic devices made of selenium have been known since the 19th Century. Pioneering research in semiconductors, which led to the invention of the transistor in 1947, formed the basis of the modem theory of photovoltaic performance. From this research, die silicon solar cell was the first known photovoltaic device that could convert a sufficient amount of the sun s energy to power complex electronic circuits. The conventional silicon cell is a solid-state device in which a junction is formed between single crystals of silicon separately doped with impurity atoms in order to create n (negative) regions and p (positive) regions which respectively are receptors to electrons and to holes (absence of electrons). See also Semiconductors. The first solar cell to be demonstrated occurred at Bell Laboratories (now AT T Bell Laboratories) in Murray Hill, New Jersey in 1954. 

A sensitizer is of paramount importance to photovoltaic performance. The sensitizer is attached to the surface of a mesoporous wide band-gap semiconductor serving as electron transporter. While the trivial ultraviolet absorption for 375 with a molar extinction coefficient (s) of 50.0 x 103 M [ cm-1 peaks at 372 nm, the s value of its low-energy band at 525 nm (mainly stemming from the intramolecular charge transfer transition) is 44.8 x 103 IVT1 cm-1 (08JA9202). 

The cell is on the verge of commercialization, offering a potential alternative for the currently used silicon-based photovoltaic devices.12 An unprecedented conversion efficiency of 11% could be manufactured from relatively cheap materials.19 The most up-to-date efficient DSSCs are based on ruthenium complexes. Several representative ruthenium sensitizers possess high extinction coefficient and high photovoltaic performance are shown in Scheme 1.15-19... 

The hole mobility of the copolymer is 1 X 10-3 cm2/V s, which well supports its outstanding photovoltaic performance. 

The solar to electric power conversion efficiency of dye-sensitized solar cells of laboratory scale (0.158 cm2), validated by an accredited photovoltaic calibration laboratory, has reached 11.1% under standard reporting conditions, i.e., air mass 1.5 global sunlight at 1000 Wm-2 intensity and 298 K temperature, rendering it a credible alternative to conventional p-n junction photovoltaic devices [68]. Photovoltaic performance data obtained with a sandwich cell under illumination by simulated AM 1.5 solar light using complex 26 are shown in Fig. 16. At 1 sun the 26-sensitized solar cell exhibited 17.73 =b 0.5 mA current, 846 mV potential, and a fill factor of 0.75 yielding an overall conversion efficiency of 11.18%. 

To compare the impact of these different morphologies on photovoltaic performance, devices are fabricated in an identical manner except for the choice of solvent (either toluene or chlorobenzene) used for spin-coating the active layer (MDMO PPV PCBM, 1 4 by wt.). Characterization of the devices is performed under illumination by a solar simulator. The AM 1.5 power... 

Toshiba developed a novel solid state chemically cross-linked gel electrolyte, which makes an irreversible three-dimensional network in the pores of TiC>2. Interestingly, no significant loss in photovoltaic performance was found compared with cells containing liquid electrolytes [21]. 

Hegedus et al. [146] also measured the I-V curves of amorphous Si p-i-n solar cells at different temperatures. The curves in the dark and also under illumination are shown in Fig. 5.25. The I-V curves under illumination obey Eq. (5.8) in this case also. The built in voltage calculated from the illuminated curves was satisfactory. Hegedus et al. [146] took small portion of the dark I-V curves which could be represented by an equation of the type (5.5). They then attempted to derive the built in voltage using this dark current as Shockley currents. They obtained very strange results. Hegedus et al. [146] wrote Our results also clearly demonstrate that it is completely inappropriate to analyze J( V) data measured in the dark on a-Si p-i-n devices and then attempt to correlate the results with photovoltaic performance Measurements in the dark are not applicable to understand-... 

Myers, D., K. Emery, C. Gueymard, Revising and Validating Spectral Irradiance Reference Standards for Photovoltaic Performance Evaluation. ASME Journal of Solar Energy Engineering, 2004. 126 p. 567-574. 

Table 1. Summary of photovoltaic performance of some conducting polymers...

Relationship between material and device parameters and photovoltaic performance... 

Nguyen L. H., Gunes S., Neugebaner H., Sariciftci N. S., Banishoeib F., Henckens A., Cleij T., Lutsen L. and Vanderzande D. (2006), Precursor route poly(thienylene vinylene) for organic solar cells photophysics and photovoltaic performance . Solar Energy Mat. Solar Cells 90, 2815-2828. 

Discovered in 1993, the photovoltaic performance of N3 has been unmatched for eight years by virtually hundreds of other complexes that have been synthesised and tested. However, in 2001 the black dye tri(cyanato)-2,2 2"-terpyridyl-4,4 4"-tricarboxylate)Ru(II) achieved 10.4% AM 1.5 solar-to-power conversion efficiency in full sunlight (Nazeeruddin et al, 2001). Conversion efficiencies have meanwhile been improved further, the current record validated by an accredited laboratory being 11.1% (Chiba et al, 2006). 

Figure 8.7 Photovoltaic performance of a state-of-the-art DSSC laboratory cell i-V curve measured under AM 1.5 standard test conditions.

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