Solar cells performance

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. 

Narayanan, R., M. Deepa, and A.K. Srivastava, Nanoscale connectivity in a Ti02/CdSe quantum dots/functionalized graphene oxide nanosheets/Au nanoparticles composite for enhanced photoelectrochemical solar cell performance. Physical Chemistry Chemical Physics, 2012.14(2) p. 767-778. 

The Correlation Between Surface Morphology and Solar Cell Performance of WSe2 and MoSe 2 Photoanodes... 

In summary, it has been demonstrated that surface morphology is critically important in determining the performance of solar cells with layered compound semiconductors. Steps on structured surfaces of transition metal dichalcogenides have been identified as carrier recombination sites. The region defined by the depth of the space charge layer parallel to the van der Waals planes can be considered as essentially "dead" in the sense that its photoresponse is negligible. As the "step model" predicts, marked improvement in solar cell performance is found on samples with smooth surfaces. 

Fig. 6.52. Dependence of solar cells performance on the front CVD ZnO preannealing temperature. Reprinted with permission from [70]...

Electrons and holes generated in the i-layer by incident light are driven to the n- and p-layer by the internal electric field, respectively. The material quality of the intrinsic layer and the strength and distribution of the electric field are responsible for the charge carrier collection and mainly determine the electrical solar cell performance. Defects affect the charge carrier collection in two different ways On the one hand they act as recombination centers, and on the other hand their charge state modifies the electric field distribution in the i-layer. 

The effect of light trapping on solar cell performance is demonstrated by ZnO Al films with different surface textures. Figure 8.8 shows scanning electron microscope (SEM) images of these ZnO Al films. Sputtered ZnO Al is initially smooth (Fig. 8.8a). By a simple wet-chemical etching step in diluted hydrochloric acid (typically 0.5% HC1) one can roughen the ZnO Al surface which is shown after a short dip (Fig. 8.8b) and after an optimized etch... 

Having established the general relationships between front contact properties and solar cell performance, this section will summarize the present status of high efficiency solar cells and modules focusing on state-of-the-art texture etched ZnO Al films as substrates. 

The principal method of characterizing solar-cell performance is the measurement of conversion efficiency while the cell is exposed to 1 sun illumination (—100 mW cm-2). The conversion efficiency is determined by measuring the current - voltage characteristic (see Fig- 8), locating the maximum power point (Pm = JmVm), and also measuring the solar insolation... 

F.A. Lindholm, J.G. Fossum, E.L. Burgess, Basic corrections to predictions of solar cell performance required by non-linearities, in Proc. 12th Photovoltaic Specialists... 

To clarify the impact of sub-GBs on solar cell performance, in particular, the shunting effect, Kutsukake et al. performed EL imaging on a small solar cell sample, in which the distribution of sub-GBs was specified by using X-ray... 

In the next sections, we review progress and approaches in six areas that are recognised as priorities for the improvement of organic solar cell performance. 

Deeper insight into CNT functionalities when used as a dopant for polymer solar cells and polymer light-emitting diodes (PLEDs) was presented by Xu et al. [329]. While the PLED gained from rather low CNT doping levels of about 0.02%, the solar cell performance increased further up to 0.2 wt %. The improved EQE of the OLED was explained by a better charge carrier injection from the electrode, whereas for the solar cell exciton dissociation is facilitated by the nanotubes [329]. 

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