Photocurrent enhancement

For a single band gap system, two basic approaches for the conversion of hot carriers into electricity or chemical energy have been proposed to enhance the efficiency of photon conversion (a) extraction of the hot carries before they cool, with the production of an enhanced photovoltage [35] (b) production of two or more electron-hole pairs per photon absorbed, with photocurrent enhancement [36, 37]. 

Photocurrent enhancements per unit absorption of more than an order of magnitude were observed relative to Rhodamine 6G. Beam coupling experiments, shown in Fig. 6, for the 37-. im thick cells resulted in beam amplification (loss) of 88% and photorefractive gain coefficients of 640 cm-1. Photorefrac-tive rise times as short as 40 msec were observed, although at the expense of photorefractive gain. This was accomplished with very low light intensities (100 mW/cm2) and low applied electric fields (0.04 V/ im) that required only a low voltage (1.5 V) battery. In addition, the samples showed no decomposition over a one-year period. 

Ward, M. D. Bard, A. J. Photocurrent enhancement via trapping of photogenerated electrons of Ti02 particles, J. Phys. Chem. 1982, 86, 3599. 

Akiyama, T., M. Nakada, N. Terasaki, S. Yamada. (2006). Photocurrent enhancement in a porphyrin-gold nanoparticle nanostructure assisted by localized plasmon excitation. Chem. Commun. 395-397. 

Strong evidence for this sensitization mechanism came from a comparison of the excited state quenching rate constant and the photocurrent enhancement by the same donor. Photoelectrochemical Stem Volmer constants were measured with the aid of Eq. 19 ... 

A pn junction was formed between p-type Pc and n-type P. Thus the spectral cosensitization effect of the cell ITO/ZnPc/tetrapyridyl(TPy)P (JO with 4-pyridyl in stead of —CgH4R)/electrolyte solution was studied The photocurrent at the Soret band for the ZnPc/TPyP electrode is 1 or 2 orders of magnitude greater than for the ITO/TPyP electrode. Such photocurrent enhancement at the ZnPc/TPyP interface may imply that the number of surface recombination centres at the pn junction is less than at mptal/dye junctions. Organic photoelectrodes based on pp iso-type junctions such as ITO/ZnPc/ZnTPP also show a cosensitization effect... 

McShane, C. M. and K.-S. Choi. 2009. Photocurrent enhancement of n-type CujO electrodes achieved by controlling dendritic branching growth. J. Am. Chem. Soc. 131 2561-2569. 

A. Kirkeminde, M. Retsch, Q. Wang, G. Xu, R. Hui, J. Wud, S. Ren, Surface-passivated plasmonic nanopyramids for bulk heterojunction solar cell photocurrent enhancement. Nanoscale 4 (2012) 4421-4425. 

N. Chander, P. Singh, A.F. Khan, V. Dutta, V.K. Komarala, Photocurrent enhancement by surface plasmon resonance of gold nanoparticles in spray deposited large area dye sensitized solar cells. Thin Solid Films 568 (2014) 74-80. 

B.P. Devi, K.C. Wu, Z. Pei, Gold nanomesh induced surface plasmon for photocurrent enhancement in a polymer solar cell, Sol. Energy. Mater. Sol. Cells 95 (2011) 2102-2106. 

Although Butler s model was successful in describing the photoelec-trochemical kinetics at certain semiconductor electrodes, it is now clear that the assumptions made in his model are valid only for very limited cases.The following experimental results suggest that the surface steps control the electrochemical reaction rate under illumination. They are (1) the Tafel-like behavior of the photocurrent-potential relations, " (2) the nonlinear relation between the photocurrent and the light intensity, (3) the photocurrent enhancement by addition of an easily reactive compound,and (4) the photocurrent enhancement by the modification of an electrode surface with metals or metal ions which catalyze the electrochemical reactionor passivate the surface recombination. Thus, only a part of photogenerated... 

Pioneering work in the area of plasmonic solar cells was performed by Stuart and Hall, who observed a 20-fold photocurrent enhancement for a... 

The ability to create and observe coherent dynamics in heterostructures offers the intriguing possibility to control the dynamics of the charge carriers. Recent experiments have shown that control in such systems is indeed possible. For example, phase-locked laser pulses can be used to coherently amplify or suppress THz radiation in a coupled quantum well [5]. The direction of a photocurrent can be controlled by exciting a structure with a laser field and its second harmonic, and then varying the phase difference between the two fields [8,9]. Phase-locked pulses tuned to excitonic resonances allow population control and coherent destruction of heavy hole wave packets [10]. Complex filters can be designed to enhance specific characteristics of the THz emission [11,12]. These experiments are impressive demonstrations of the ability to control the microscopic and macroscopic dynamics of solid-state systems. 

Wang, X. F., Y. Koyama, H. Nagae, Y. Yamano, M. Ito, and Y. Wada. 2006. Photocurrents of solar cells sensitized by aggregate-forming polyenes Enhancement due to suppression of singlet-triplet annihilation by lowering of dye concentration or light intensity. Chem. Phys. Lett. 420 309-315. 

Quantum dots (QDs) on various matrices has been extensively studied for their promising optoelectronic applications. To enhance the photocurrent generated by... 

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