Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics.

In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.

[Organic solar cell based on alkylthiol/Au self-assembly film as buffer layer].

The interface modification between the organic active layer and the inorganic electrode affects the performance of organic solar cell (OSC). A buffer layer of alkylthiol (ethanethiol, hexanethiol, dodecanethiol)/Au self-assembly layer was introduced into OSC to substitute Poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS) layer, in order to improve the organic/inorganic interface. We fabricated devices with structure of "ITO/Au (annealed Au film of 2 nm)-thiol self assembly layer/poly(3-hexylthiophene) : 1-(3-methoxycarbonyl) -propyl-1-phenyl-(6,6)C61(P3HT : PCBM) /LiF/Al".

[All wavelength picosecond fluorescent anisotropy of aligned MEH-PPV/PVP electrospun fibers].

Electrospinning is a simple and effect technology which can produce continuous nanofibers. We get aligned electrospun nanofibers successfully by using parallel electrodes. We report our studies on transient fluorescence of aligned electrospun fibers.

The improvement of bulk-heterojunction order in polymer photovoltaic device.

The blend morphology and vertical arrangement are critical to the performance of organic bulk-heterojunction photovoltaic devices. In the present paper, the authors proposed a new annealing method that controls the blend morphology and vertical arrangement of two materials by means of simultaneously applying external electrical field and violet irradiation on the active layer of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) during annealing process. By using this annealing method, the power conversion efficiency increased by 36%, which was caused by vertical phased-separated blend of crystalline P3HT and PCBM and better charge extraction of electrodes.

[Optimization of optical parametric amplification on femtosecond fluorescence spectra by referring to cone emission].

Femtosecond time-resolved fluorescence spectra technique based on non-collinear optical parametric amplification is a new method for ultrafast spectroscopy research In the present report, the authors discuss the dynamic range for amplifying fluorescence. The supercontinuum seed can be amplified linearly to its transient intensity. Due to large amplification ratio up to 10(7), small instability in pump pulse energy produces large fluctuation in final output amplitude.

[Improvement of the power conversion efficiency in organic solar cells].

Energy is most important issue in the world now because the chemical energy (oil, natural gas, coal et al) is on the edge of depleting. Many Countries are now paying attention to the use of sun power. Photovoltaic device is the most important way to make use of sun energy.

[Enhanced V(oc) in photovoltaic cell by electrodeposited polythiophene thin film].

Poly(3-hexylthiophene) (P3HT) thin films were electrochemically deposited directly on indium tin oxide (ITO)/poly (3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT : PSS) substrates. Its optical absorption peak is located at about 410 nm and tailing to 610 nm, corresponding to 2.04 eV of bandgap.

[Study of photochemically converted PPV films].

The authors present photoluminescence (PL) and Raman spectra of PPV converted in vacuum by ultraviolet(UV) irradiation which indicate partial conjugation similar to thermally converted poly(p-phenylene vinylene) (PPV). The authors have fabricated OLEDs based on photo-converted PPV. Though the electroluminescence (EL) spectra are poor, doped PPV-based OLED devices are achieved.

Widening of Long-range femtosecond laser filaments in turbulent air.

The influence of air turbulence on the long-range filamentation of femtosecond laser pulses has been numerically investigated. Simulations are performed for different parameters of air turbulence and laser pulses. Simulation results indicate that the diameter of filaments formed by free propagated fs laser pulse can be widened to mm level under air turbulence.

[High contrast organic light-emitting diodes using pb-LiF as cathode].

A metal-insulator complex film made by co-evaporating metal Pb and transparent insulator LiF was tested as a low-reflecting cathode to realize high contrast organic light-emitting diodes (OLED). The optical reflectivity and electrical characteristic of the high contrast OLED were studied as compared with the device based on Al as the cathode. The reflectivity of the Pb-LiF complex cathode is 18% only, about 5 times lower than that of Al cathode.