Single junction

Amorphous Silicon. Amorphous alloys made of thin films of hydrogenated siUcon (a-Si H) are an alternative to crystalline siUcon devices. Amorphous siUcon ahoy devices have demonstrated smah-area laboratory device efficiencies above 13%, but a-Si H materials exhibit an inherent dynamic effect cahed the Staebler-Wronski effect in which electron—hole recombination, via photogeneration or junction currents, creates electricahy active defects that reduce the light-to-electricity efficiency of a-Si H devices. Quasi-steady-state efficiencies are typicahy reached outdoors after a few weeks of exposure as photoinduced defect generation is balanced by thermally activated defect annihilation. Commercial single-junction devices have initial efficiencies of ca 7.5%, photoinduced losses of ca 20 rel %, and stabilized efficiencies of ca 6%. These stabilized efficiencies are approximately half those of commercial crystalline shicon PV modules. In the future, initial module efficiencies up to 12.5% and photoinduced losses of ca 10 rel % are projected, suggesting stabilized module aperture-area efficiencies above 11%. 

The Peltier effect at a single junction is therefore equal to the absolute, temperature of the junction multiplied by the rate of... 

Deposition has been carried out on architectural glass yielding single-junction amorphous silicon with an efficiency of 13% in the laboratory, but with lower efficiency in production devices. An atmospheric-pressure deposition system in shown in Fig. 15.5. The gas injection device is shown in Fig. 15.6. 

Single-junction single crystal 30% (CdTe) copper indium diselenide (CuInSe2)... 

FIG. 72. Schematic cross-section of (a) a single junction p-i-n o-Si H superstrata solar cell and (b) a tandem solar cell structure. (From R. E. I, Schropp and M. Zeman. "Amorphous and Microcrystalline Silicon Solar Cells—Modeling, Materials and Device Technology," Kluwer Academic Publishers, Boston, 1998, with permission.)... 

Individual cells in multijunction cells are more stable, due to their reduced thickness compared to single-junction cells. Moreover, as the amount of light that is absorbed in the bottom cell is reduced and as the degradation rate is reduced at lower light levels, the stability is improved [606]. Therefore the multijunction cell is expected to be more stable than a single-junction cell of the same thickness, which indeed has been demonstrated [577, 606-608]. 

Ideally, all photons with a wavelength of about 900 nm or shorter should be harvested and converted to electric current. This limit is derived from thermodynamic considerations showing that the conversion efficiency of any single-junction photovoltaic solar converter peaks at approximately 33% near the threshold energy of lAeV.1 2 There are numerous ways to convert the solar radiation directly into electrical power or chemical fuel. The silicon solar cell is the most efficient in this respect. Nevertheless, the capital cost of such devices is not attractive for large-scale applications. 

The RF SQUID is formed from a single junction in a superconducting loop, which is inductively coupled to a resonant circuit. This is arranged to drive a current round the loop, so that the voltage across the circuit is a measure of the magnetic flux being measured. 

In the following we will present results of a single-junction conductance study with 44-BP under electrochemical potential control, enabling the precise tuning of the molecular orientation, relative to the substrate, upon application of an adjustable gate voltage [290] in a well-controlled environment [86, 302]. 

STM-BJ experiments were performed to extract single-junction conductances of 44-BP bridged between a gold STM tip and an Au (111) substrate in non-polar solvents, such as mesitylene, isopropanol, and 1,2,4-trichlorobenzene, as well as under full electrochemical potential control in aqueous solutions of HCIO4 and LiClOq at various pH. 

Figure 25a, as an example, shows the potential dependence of the single-junction conductances of 44-BP measured in 0.1 M HCIO4 solution (pH 1) in —0.10 V < E < 0.90 V in a semi-logarithmic representation. The values of L, M, and H decrease with more positive electrode potentials, and follow nearly the same trend for each family. The single-junction conductances decrease by a factor of 3-5 upon potential excursion towards positive values in the accessible potential region. A similar trend is also observed for electrolytes with variable pH ranging between 1 and 10, as... 

The statistical analysis of these traces revealed all-data-point and plateau-counting histograms with a series of uniformly spaced current peaks (Fig. 28b). The first peak of each sequence could be identified as the single-junction conductance current. The data set of T-PBI plotted in Fig. 28b leads to 21.7 3.8 nS at Es = —0.820 V. 

Single-jet crystal growth method, 19 179 Single-junction crystalline solar cells, 23 41-42... 

Fig. 18a.2. Schematic of a single-junction Ag/AgCl reference electrode.

C being the self-capacitance of the junction, U (current bias term included —U() = (ft/2e)(/c cos) for a single junction. Further we concentrate on overdamped junctions where C -C G2H/(2eIc) and neglect the capacitance term. The normal conductor part we write following [11] in quasi-stationary approximation... 

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