Design of highly transparent organic photodiodes

In this brief, various approaches for the realization of transparent photodiodes based on bulk heterojunction blends of poly-3-hexylthiophene and [6,6]-phenyl C-61-butyric acid methyl ester are studied. The choice of the constituents of the device is discussed concerning transmittance and light-detecting properties as dark current and external quantum efficiency (EQE). Blending several light-absorbing materials makes tailoring of the transmittance spectrum possible. Transmittance of 36% of the incident light together with 46% EQE at a wavelength of 530 nm are promising results and show the potential for highly transparent, photodiodes based on organic layers

Dynamic and steady state current response to light excitation of multilayered organic photodiodes

Measurements of current transients are used to gain insight into the mechanism of charge transport and extraction of photodiodes based on bulk heterojunction blends of poly-3-hexyl-thiophene and [6,6]-phenyl C-61 butyric acid methyl ester. It is shown that the implementation of an appropriate hole conducting layer leads to a reduction of the dark current in the reverse direction. It is observed that the dynamic response to light excitation is strongly influenced by the thickness of the hole conducting layer, the light intensity, and the applied bias. Charge accumulation at the interface is assumed to result in the characteristic shape of the transients. The shape of the switch-off transient can be understood qualitatively by an equivalent circuit diagram. (c) 2007 American Institute of Physics

Fuzzy polynucleotide spaces and metrics

The study of genetic sequences is of great importance in biology and medicine. Mathematics is playing all important role in the study of genetic sequences and. generally, in bioinformatics. In this paper, we extend the work concerning the Fuzzy Polynuclotide Space (FPS) introduced in Torres, A., Nieto, J.J.. 2003. The fuzzy polynuclotide Space: Basic properties. Bioinformatics 19(5)-, 587592 and Nicto, J.J.. Torres, A.. Vazquez-Trasande, M.M. 2003. A metric space to study differences between polynucleotides. Appl. Math. Lett. 27:1289-1294 by studying distances between nucleotides and some complete genomes using several metrics. We also present new results concerning the notions of similarity, difference and equality between polynucleotides. The results are encouraging since they demonstrate how the notions of distance and similarity between polynucleotides in the FPS can be employed in the analysis of genetic material