Sensitizer spectral response

The major characteristics of the photomultiplier with which the user is generally most concerned include (1) sensitivity, spectral response, and thermal emission of photocathodes (2) amplification factor and (3) noise characteristics and the signal-to-noise ratio. 

The polymer influences many properties of the resist system. These properties are divided into two categories physical and functional. Thus, viscosity, solid content, solvent compositions and molecular weight distribution of the polymer are important physical properties. The functional properties include sensitivity, spectral response, contrast, adhesion to the substrate, development conditions, thermal flow, plasma resistance, and planarization capability. 

A medically reliable UV sensor should have a spectral responsivity that closely follows the erythemal curve between 390 nm and 290 nm. So far, a photodiode with this specific sensitivity has not been available. Modeling the erythema spectrum with the help of filters also delivered only poor results. In fact, most available sunburn detectors vary in their spectral responsivity and may therefore only be used as an indicator for the actual UV charge. 

A photodetector with a suitable spectral response for the detection of the fluorescence emission. As mentioned above, the fluorescence of most Cr3+-activated materials consists of either the red R-lines or a broadband infrared emission with the peak wavelengths ranging from -750 to 1000 nm, or both emissions. Thus, the widely available, compact and inexpensive silicon PIN photodiodes are the most suitable photodetectors for these applications. In some particular circumstances, where high speed and high sensitivity of detection are required, a silicon-based avalanche diode could be the best alternative to the PIN photodiode, at small price premium ... 

The use of a linear detector array in the image plane of a polychromator in place of the fluorescence monochromator in Figure 12.1 enables the parallel data accumulation of complete fluorescence spectra. Silicon photodiode arrays, operated in a CCD mode(34) are the most widely used detector elements. The spectral response of the diodes enables fluorescence to be detected from the near-UV up to ca. 1100 nm with a peak response in the near-IR. Up to 8192 elements are now available commercially in a single linear array at low cost. However, the small length of each element (ca. 10 [im) presently limits sensitivity and hence cylindrical lens demagnification is often necessary. 

Responsivity (spectral sensitivity) The response or sensitivity of any sys-fem in ferms of incidenf wavelength. In radiometry, it is the output... 

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 ... 

Figure 8 Spectral responses (IPCE) of N3- and black dye-sensitized 2 solar cells. IPCE is plotted as a function of wavelength. (Data from Ref. 20.)...

The total efficiency of the solar cell depends on the current, voltage, and the fill factor of the cell. Many groups have focused on the development of new sensitizers, which exhibit visible spectral response that matches the solar spectrum [15,20,35,47,50,82,84-86]. The open-circuit photovoltage is one of the key fac-... 

It was found that preliminary ultraviolet irradiation alters the photoelectrical sensitivity. Figure 23 represents the spectral response curves for the photoconductivity (curve 1) and the photoelectromotive force (curve 3) of poly (PiP -diethynylazobenzene). 

Typical results are shown in Fig. 44. The spectral threshold of the proper photoconductivity and the photo-emf of PAC is situated at 520 nm. The spectral response for the photo emf of PAC itself is shown by curve 1. After PAC has been immersed in an ethanol solution of methylene blue and dried its spectral response is represented by curves 2 and 2. The photo-response appears in the range of the absorption maximum of the dye at 680 nm characteristic of the monomolecular form in the dilute initial solution (curve 3). The observed enhancement of the second maximum at 620 nm in comparison to the solution spectrum is obviously connected with the presence of dye dimers. The shift of the maximum photoresponse to the longer wavelength by 15 nm relatively to the solution is usually the case for the adsorbed state. The sign of the charge carriers both in the proper and sensitized spectra ranges is positive. As seen in Fig. 44 the adsorption of the dye also markedly changes the proper photosensitivity of the PAC. When the monomolecular form of the adsorbed dye dominates, the... 

There are also instruments with dispersion surfaces compatible with two-dimensional sensors. Their sensitivity and spectral response allow simultaneous measurement of thousands of lines (Fig. 15.7). 

From its principle of operation, a broadband detector provides a signal proportional to the integral of solar radiation 1(1), weighted by its relative spectral responsivity w(X), over its entire sensitivity range. Therefore, the eiythemal dose rate E given in units of W ffm 2 can be than given from (1) ... 

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