Charge carrier lifetime

The PMC transient-potential diagrams and the equations derived for PMC transients clearly show that bending of an energy band significantly influences the charge carrier lifetime in semiconductor/electrolyte junctions and that an accurate interpretation of the kinetic meaning of such transients is only possible when the band bending is known and controlled. 

Warman JM, de Haas MP, Anthopoulos TD, de Leeuw DM. (2006) The negative effect of high-temperature annealing on charge-carrier lifetimes in microcrystalline PCBM. Adv Mater 18 2294-2298. 

The distance d that charge carriers can travel within the device is a product of charge carrier mobility fi, charge carrier lifetime r, and the internal electric field F ... 

T , (Tp Effective cross-section of electron (n) or hole (p) scattering on a trap T Charge carrier lifetime... 

As shown in Fig. 22, the carrier density within the blend layer changes with illumination intensity 7, cell voltage V, and temperature T. Combining n(l, V, T) with charge carrier lifetime data determined with TPV at comparable carrier densities allows calculation of the loss current density /ng via Eq. (8). Finally, the current characteristics under steady-state illumination are reconstructed with the assumption of a field-independent generation current density, /gen —- sc- This approach has been successfully applied to both as-prepared and annealed P3HT PCBM layers [173,205]. The data in Fig. 22c, d also show that the annealed device displays larger carrier lifetimes and lower recombination coefficients than the as-cast sample at comparable carrier densities. This has been quoted as the main cause for the superior performance of the thermally treated sample [173, 205]. 

A champion CIGS-based thin film solar cell was prepared and characterised at NREL by Repins et al A record efficiency of 19.9% was measured for a 0.41 cm device in which, during the latter stages of vacuum deposition (100 A), the chalcopyrite was deposited without gallium, improving the quality of the material near the surface by reducing the number of surface defect states. An improved (5.5 ns) charge carrier lifetime was measured and a maximum carrier density of 2 x 10 cm was measured. 

An important consequence for DSSCs of the use of the highly ordered nanotube arrays in comparison with nanoparticulate systems, is the improvement in photogenerated charge carrier lifetimes by well over an order of magnitude. " " Zhu et used frequency-resolved,... 

Debije, M.G., Chen, Z., Piiis, J., Neder, R.B., Watson, M.M., Mullen, K., Wurthner, R Dramatic increase in charge carrier lifetime in a liquid crystalline perylene bisimide derivative upon bay substitution with chlorine. J. Mater. Chem. 15, 1270-1276 (2005)... 

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