Photo-bleaching response in chlorophyll solutions

Mirchin, N.; Peled, A.

doi:10.1016/j.apsusc.2005.03.086

Cited by 4 publications

(2 citation statements)

References 10 publications

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“…For curve 4 this procedure needs some caution while transients 5 and 6 are totally featureless denying such an approach. It is seen that the flat plateau for the first two curves gradually gives way to gently (3) and then strongly (4) sloping plateaus (shoulders) which end up as featureless curves (5,6).…”

Section: Tof-1a Datamentioning

confidence: 99%

“…Charge carrier transport in molecularly doped polymers (MDP) has been extensively studied since the 1970s but still seems to be not properly understood. It suffices to say that at least 5-7 theories are in use for interpretation of the field, temperature and concentration (of dopant molecules) dependences of the drift mobility of charge carriers [1][2][3][4][5][6]. Of course, two main competing theories need to be noted.…”

Section: Introductionmentioning

confidence: 99%

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Verification of the dispersive charge transport in a hydrazone:polycarbonate molecularly doped polymer

Tyutnev

Saenko

Pozhidaev

et al. 2009

J. Phys.: Condens. Matter

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We report results of specially planned experiments intended to verify the dispersive character of the charge carrier transport in polycarbonate molecularly doped with hydrazone at 30 wt% loading, using for this purpose samples specifically featuring a well-defined plateau on a linear-linear plot. For this purpose we propose a new variant of the time-of-flight technique which allows easy changing of the generation zone width from about 0.5 µm (surface excitation) through intermediate values to full sample thickness (bulk excitation). To achieve this, we use electron pulses of 3-50 keV energy rather than traditional light pulses provided by lasers. Experimental results corroborated by numerical calculations uniquely prove that carrier transport in this molecularly doped polymer is dispersive, with the dispersion parameter equal to 0.75. Nevertheless, the mobility field dependence follows the famous Poole-Frenkel law.

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Section: Tof-1a Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Verification of the dispersive charge transport in a hydrazone:polycarbonate molecularly doped polymer

Tyutnev

Saenko

Pozhidaev

et al. 2009

J. Phys.: Condens. Matter

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Switching Light With Light in Chlorophyll-A Molecules Based on Excited-State Absorption

Roy

Kulshrestha²,

Prasad

2009

IEEE Trans.on Nanobioscience

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We analyze all-optical switching in chlorophyll-A (Chl-A) molecules for different combinations of pump-probe wavelengths, based on nonlinear intensity-induced excited-state absorption. It is shown that for a pulsed pump beam at 672 nm with peak pump intensity of 5 kW/cm(2) and Chl-A concentration of 1.5 mM, the transmission of a continuous-wave probe beam at 476 nm can be completely switched off (100% modulation) with switch on-off time of 0.58 and 0.18 micros, respectively. It is also shown that the switching characteristics can be inverted by changing the probe beam wavelength. The effect of various parameters, such as concentration, pump beam intensity, pump pulse width, absorption cross section of the ground state, and lifetimes of different states, on the switching characteristics has been analyzed in detail. It is shown that there exists an optimum value of concentration of Chl-A for maximum switching contrast, for the case when the ground state also absorbs the probe beam. The switching characteristics of Chl-A have also been compared with Chl-B and Bchl. Experimental results for all-optical switching in Chl-A with a train of pulses are in good agreement with theoretical results. It is shown that higher contrast and faster switching can be achieved as opposed to what was reported recently in other biomolecules such as archael rhodopsin and phototropin proteins. The results have also been used to design switches and logic gates.

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Bleaching of chlorophylls by UV irradiation in vitro: The effects on chlorophyll organization in acetone and n-hexane

Zvezdanović¹,

Marković²

2008

J Serb Chem Soc

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The stability of chlorophylls toward UV irradiation was studied by Vis spectrophotometry in extracts containing mixtures of photosynthetic pigments in acetone and n-hexane. The chlorophylls underwent destruction (bleaching) obeying first-order kinetics. The bleaching was governed by three major factors: the energy input of the UV photons, the concentration of the chlorophylls and the polarity of the solvent, implying different molecular organizations of the chlorophylls in the two solvents.

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Photo-bleaching response in chlorophyll solutions

Cited by 4 publications

References 10 publications

Verification of the dispersive charge transport in a hydrazone:polycarbonate molecularly doped polymer

Verification of the dispersive charge transport in a hydrazone:polycarbonate molecularly doped polymer

Switching Light With Light in Chlorophyll-A Molecules Based on Excited-State Absorption

Bleaching of chlorophylls by UV irradiation in vitro: The effects on chlorophyll organization in acetone and n-hexane

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