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The comparison of performance of positive electrodes of lithium-sulfur batteries made using the binders based on fluoroplastic (PVDF Solef 5310 and Kynar) and polyethylene oxide (PEO) was carried out. The electrodes made using PVDF Kynar or limited amounts of PEO were shown to have certain advantages. It was also found that electrodes with PEO had an increased specific capacity during the initial period of cycling, whereas electrodes with Kynar were characterized by the minimum capacity fading during cycling.

We measured the picoseconds (ps) transient photomodulation (PM) dynamics of photoexcitations in blends of regio-regular poly(3-hexyl-thiophene) [RR-P3HT] (donors-D) and indene-C60 bisadduct (fullerene derivative) [ICBA] (acceptor-A) that phase-separate into D- and A-nano-domains, in a broad spectral range from 0.25 to 2.5 eV; in comparison with steady state PM spectra. We correlate our measurements with organic photovoltaic solar cell performance made from the same D and A materials. In D-A blends of RR-P3HT/ICBA with (1.2:1) weight ratio having solar cell power conversion efficiency of ∼5.1%, we found that although the intrachain excitons in the polymer nano-domains decay within ∼10 ps, no charge polarons are generated on their expense up to ∼1 ns. Instead, there is a built-up of charge-transfer (CT) excitons at the D-A domain interfaces that occurs with the same kinetics as the exciton decay. The CT excitons dissociate into separate polarons in the D- and A-nano-domains at a much later time (>1 ns). This 'two-step' charge photogeneration process is typical in organic bulk heterojunction cells. Our results emphasize the important role of the CT state in generating free charge polarons in organic solar cells. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, a new cathode material for lithium–sulfur (Li–S) batteries was developed. Microporous carbon (with predominant pore size £ 1.2 nm) served as both a matrix for sulfur retention and conductive additive. Microporous carbon was shown to be capable of adsorbing lithium polysulfides thereby suppressing their migration toward lithium anode. The discharge capacity of the S/C composite at the 1st and 20th cycles in Li–S battery operation was 513 and 421 mAh g–1 at a scan rate of 0.1 mV s–1. [ABSTRACT FROM AUTHOR]

We employed a cross correlation method to study current noise in phosphorescent organic light-emitting diodes. The noise spectra revealed two frequency-dependent components. The first component displays \({1/f}^{1.3}\) dependence and correlates with the light emission of the devices. The second component is dominant in low-bias regime and varies as \({1/f}^{2.8}\) . It is attributed to inhomogeneities of the barrier height at metal/organic interface. The extended bandwidth of the method allowed us to resolve frequency-independent term in the noise power, which was dominated by the shot noise. At bias voltages from 2.4 to 2.5 V, the Fano factor characterizing shot noise is close to one, confirming that the electron transport in this regime is limited by the carrier injection across metal/organic interface. At higher biases, in the regime where the transport is bulk-limited, the Fano factors drops to 0.5. Possible physical reasons for such behavior are discussed. [ABSTRACT FROM PUBLISHER]

In this paper, a technique based on the auto correlation Junction is proposed to estimate the Doppler spread in Rayleigh fading channels for mobile OFDM systems. It is simply implemented with the cyclic structure of OFDM symbols, and any other additive data and pilots need not to be inserted into the common OFDM symbols. This algorithm can be applied directly to the OFDM system with transmit diversity (TD) and to MIMO OFDM systems. Computer simulation results are included to support our developments in the terms of mean estimation value and mean square error. [ABSTRACT FROM AUTHOR]

We present recent developments of our core technologies targeted towards solution based OLED device manufacturing including non-aqueous (NQ) hole injection layer and solution processed hole transport layer. We demonstrate low voltage, and long lifetime devices with non-aqueous hole injection layer. Also, comparable performance with our intractable solution processed HTL versus NPB vapor HTL has been demonstrated in vapor WOLED devices in combination with our NQ hole injection layer technology. [ABSTRACT FROM AUTHOR]