Lifetime productivity

Besides cTph and the photoresponse, the quantum-efficiency-mobility-lifetime product, r]gfj.r, is used as a figure of merit. Usually this product is measured at a wavelength of 600 nm, and typical valuesof (r/i /ur)6oo are lO cm A/ or higher. 

In the presence of an electric field the drift length is the mobility-lifetime product times the electric field A.mfp = prE [576]. With typical values of pz and E the mean free path usually exceeds by far the thickness of the solar cell, and virtually all photogenerated carriers can be collected. However, under certain operating conditions, field-free regions in the / -layer may exist, and the collection efficiency is decreased because the diffusion lengths of the carriers are much smaller than the thickness of the solar cell [11, 577]. 

H Antoniadis, MA Abkowitz, and BR Hsieh, Carrier deep-trapping mobility — lifetime products in poly(p-phenylene vinylene), Appl. Phys. Lett., 65 2030-2032, 1994. 

V Adamovich, RC Kwong, MS Weaver, M Hack, and JJ Brown, Maximizing the Efficiency Lifetime Product for Phosphorescent OLEDs, Proceedings of the International Display Research Conference, Daegu, 2004, pp. 272-276. 

Figure 5.9 Hole and electron drift mobility lifetime product /xt and residual potential versus Te content in a-Scj- Te films. The /xt product was xerographically measured by Abkowitz and Markovics [14].

While an [S]/[C] ratio serves as a good dimension of merit for the productivity of one batch, it does not yield any information on the stability of the catalyst over its lifetime. As already discussed in Chapter 19, Section 19.3.4, the homogeneous catalysis community typically does not feel the need to recycle catalysts (Blaser, 2001), so the turnover number (TON) equals the total turnover number (TTN). The true utility and productivity advantage of biocatalysts is captured upon reuse of the catalyst, achieving catalyst lifetime productivities far in excess of catalysts used only once. 

The low defect density in compensated material is apparent from the optical data in Fig. 5.18, which show a much reduced defect absorption band. The same result is deduced from time-of-flight and ESR data. Although the drift mobility is low, the mobility-lifetime product is comparable with the best undoped material, confirming the low defect density (see Fig. 8.24). The dangling bond density in the dark ESR experiment is about 4x10 cm" , with little dependence on the doping... 

Valerian and Nespurek (1993) determined values of the electron range (mobility-lifetime product) of vapor-deposited a-H2Pc from measurements of the photocurrent action spectra. The values were about 6 x 10-12 cm2/V, considerably lower than 10-9 cm2/V reported earlier by Popovic and Sharp (1977) for /J-H2Pc. For further discussions of photoconductivity in n-type phthalocyanies, see Schlettwein et al. (1994, 1994a), Meyer et al. (1995), and Karmann et al. (1996,1997). 

A finite carrier range (3) refiects the infiuence of deep traps and is controlled by the mobility-lifetime product ( xt). By using the numbers just given, (XT in practical polymeric TL should exceed 10 cm /V substantially. 

Figure 6.18 Results from junction-recovery measurements on Sn02/Ti02/Au diodes. The electron drift mobility and the mobility-lifetime product are determined for various injection conditions and forward bias. The electron mobility is found to increase with increasing injection level, while the mobility-lifetime product remains approximately constant. These findings can be consistently explained in a transport model based on trap filling and a transport-limited recombination mechanism. An alternative explanation can, however, also be based on a tunnelling transport model (Konenkamp, 2000a).

If the total energy and emissions of a battery during its entire lifetime production, use, maintenance and disposal are established, then divided by the total lifetime energy of the battery, the total emissions per kilowatt-hour of energy may be derived. These are separated into specific materials, usually elements, compounds or groups of compounds, for which specific environmental and/or human health impact assessment values are available. Utilizing these values, the overall relative life cycle environmental impact of a particular battery system may be established and compared to other battery systems. As previously discussed, these analyses involve many assumptions and... 

Internal photoemission of holes and electrons into KN3 was studied by de Panafieu and Royce [66]. Analysis of the results provided values for a number of important material parameters The band-gap value of 8.44 0.25 eV is consistent with the 8.55 eV obtained from Deb s absorption measurements [48] and with the theoretical model of Section C.2.b. At room temperature the mobility-lifetime product (range) /zr = (1.8 0.2) X 10" cm V" for electrons, and (6 2) X 10" cm V for holes. The electron affinity value 0.3 eV is consistent with Deb s photoemission data [142] if one interprets the rapid rise in his emission at 8.7 eV as being the threshold. 

Any comparison between different materials, regarding their suitability for an application, must be related to the processes involved and thence to the optimum levels of production. For something as large and complex as a car body, the analysis of the break even points is absolutely crucial. Factors such as model lifetime, production levels, tool costs, material prices and production rates must be taken into account, as well as less predictable market forces. 

Nn initial charge density in traps piT a charge mobUity-free lifetime product ft a penetration de of charge c a dielectric permittivity d a sample thickness p a dipole moment E, a electret forming field r a electret forming temperature e a electronic charge dipole concentration... 

In order to ensure lifetime product quality, MID are reliability-tested by subjection to stress factors replicating the conditions prevailing in subsequent use. Stress factors applicable for a wide range of MID applications include... 

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