Photovoltaic elements

Semiconductor High-power transistors High-power microwave Photovoltaic elements Field-effect transistors UV sensors... 

Schottky photovoltaic elements were proposed because of the good conformity of the solar spectrum with the polyacetylene forbidden gap. The photovoltaic spectra for (CH)n-Al structure and volt-current characteristic for (CH) -nCdS heterojunction are presented in Fig. 19 and Fig. 20 respectively. 

This semiconductor has the optimum bandgap for sunlight conversion (1.42 eV) and so, like Si, is commonly used for solid-state photovoltaic elements. In our case the complete water decomposition for hydrogen and oxygen does not take place. 

It is indeed intriguing and very attractive to think of photovoltaic elements based on thin plastic films with low cost but large areas, cut from rolls and deployed on permanent structures and surfaces. In order to fulfil these requirements, cheap production technologies for large scale coating must be applied to a low cost material class. Polymer photovoltaic cells hold the potential of such low cost cells. Flexible chemical tailoring of desired properties, combined with the cheap technology already well developed for all kinds of plastic thin film applications, precisely fulfill the above-formulated demands for cheap photovoltaic device production. The mechanical flexibility of plastic materials is welcome for all photovoltaic applications onto curved surfaces in indoor as well as outdoor applications. 

Recently, Cravino et al. have also addressed the importance of device layout (size and shape) on the evaluation of device performance. They emphasized that devices with crossing electrodes and impatterned organic layers can collect a nonnegligible current from regions usually not considered as part of the photovoltaic element. This fact may lead to an overestimation of the power conversion efficiency (PCE). 

A frequently used organic gate dielec-FIGURE 10.16 Photovoltaic element based on polymers, material is poly-4-vinyl phenol (PVP)... 

The semiconductor properties of metal clusters can help to develop new and more effective photovoltaic elements. 

Fortunately, such a microscope can now be fitted with a multi-element detector to measure multiple areas simultaneously. One multi-element detector approach is to construct quasi-lD arrays from the same Hgi xCdxTe photo-conductive material as for a single-element detector, providing essentially the same spectral range and performance. Each element can be individually biased and read-out by an AC coupled amplifier having bandwidth compatible with FT-IR scanner velocities of 1 cm/s or above. Larger area, 2D arrays are usually made with photovoltaic elements i.e. photodiodes) to avoid the current biasing... 

Figure 5 Model of a photovoltaic element based on Bolton s design. The top electrolyte layer is symbolized here by a porous amphiphile layer.

Organic solar cells (OSCs) have gained considerable interest within the last decade as forward-looking technology enabling the production of photovoltaic elements by roll-to-roll deposition, for example, by printing or vacuum sublimation. ... 

The other class of detectors is based on the effect infrared photons exert directly on electrons in semiconducting materials such detectors are called photon or quantum detectors, a somewhat unfortunate name because thermal detectors absorb photons or quanta as well. The energy of an absorbed infrared photon may not be high enough to cause emission of an electron by the photoelectric effect, but it is sometimes sufficient to lift an electron from a valence band into a conduction band, thereby altering the macroscopic properties of the material. The change in the electrical resistance (in photoconductors) or in the electrical potential (in photovoltaic elements) may then be sensed electrically. 

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