Transparent, highly percolated networks of regio-regular poly(3-hexylthiophene) (rr-P3HT) wrapped semiconducting single walled carbon nanotubes (s-SWNT) are deposited and the charge transfer processes of these nanohybrids are studied using spectroscopic and electrical measurements. The data discloses hole doping of s-SWNTs by the polymer, challenging the prevalent electron doping hypothesis. Through controlled fabrication, high to low-density

Photoluminescence quenching is observed in acid functionalized multiwall carbon nanotubes incorporated polymer: fullerene films, suggesting efficient charge transfer, believed to be due to nanotubes acting as exciton dissociation centres. The fabricated photovoltaic devices with triple heterojunction interfaces show increased short circuit current density compared to the device without nanotubes.

Pulse laser ablation and subsequent laser nanostructuring at room temperature has been employed to produce nanostructured Ni on SiO 2 /Si substrates for catalytic growth of carbon nanotubes. The resultant nanostructured surface is seen to consist of nanometer sized hemispherical droplets whose mean diameter is controlled by the initial metal thickness, which in turn is readily controlled by the number of laser pulses. Vertically aligned multiwall carbon nanotube mats were then grown using conventional plasma enhanced chemical vapor deposition. We show that within a single processing technique it is possible to produce the initial metal-on-oxide thin film to a chosen thickness but also to be able to alter the morphology of the film to desired specifications at low macroscopic temperatures using the laser parameters. The influence of the underlying oxide is also explored to explain the mechanism of nanostructuring of the Ni catalyst.

Excimer laser crystallization is used to produce layered nanocrystalline silicon from hydrogenated amorphous silicon, using a partial melting process. Three types of hydrogenated amorphous silicon samples, 100, 300, and 500 nm thick, were laser treated in order to investigate the changes to the structural, optical, and electrical properties as a function of amorphous silicon thickness with excimer laser crystallization. The resulting nanocrystalline thin films were characterized using Raman spectroscopy, optical absorption measurements, atomic force microscopy, forward recoil spectrometry, and current-voltage measurements. The relationship of crystalline volume and laser energy density was established, along with the behavior of the optical gap and its relationship to hydrogen content. Surface roughness effects are discussed in the context of photovoltaic applications. The effect of increased mobility on photoconductivity after excimer laser crystallization is also examined.

Abstract-Solution processed photovoltaic devices are an attractive alternative to costly inorganic semiconductor based conventional photovoltaics. Solution processable organic photovoltaic systems are affected by low carrier mobility, lifetime issues under ambient conditions and limited optical absorption due to the high bandgaps of organic materials. Nanostructured inorganic materials promise to alleviate some of these drawbacks, by enabling the hybrid systems to perform better in a commercial perspective. This review examines four key areas of hybrid organic-inorganic photovoltaic systems. These are metal oxide-organic, carbon nanotube-organic, semiconductor nanowire-organic and semiconductor nanocrystal-organic systems, which are showing growing importance and potential in the literature. Recent advances in terms of device performance for these respective topics are reviewed, along with an outlook for each hybrid system.

Multiwall carbon nanotubes are introduced into poly͑3-hexylthiophene͒ and ͓6,6͔ phenyl C 61 butyric acid methyl fullerene, bulk heterojunction organic photovoltaic devices. Utilization of nanotubes requires chemical modifications for compatibility with solution processable photovoltaics. Better dispersions of carbon nanotubes in organic solvents are achieved by acid functionalization of tubes. Pristine and acid treated multiwall carbon nanotubes have been incorporated into the photoactive layer and better results in fill factors of 62% and efficiency of 2.3% are achieved under Air Mass 1.5 Global illumination through the use of acid treated nanotubes.

A novel and compact nanoindentation device for in situ nanoindentation tests inside the scanning electron microscope AIP Advances 2, 012104 (2012) Invited Review Article: Photopyroelectric calorimeter for the simultaneous thermal, optical, and structural characterization of samples over phase transitions Rev. Sci. Instrum. 82, 121101 (2011) Nanometer optomechanical transistor based on nanometer cavity optomechanics with a single quantum dot J. Appl. Phys. 110, 114308 (2011) Breakover mechanism of GaAs photoconductive switch triggering spark gap for high power applications J. Appl. Phys. 110, 094507 (2011) Additional information on J. Appl. Phys. co-doped Y 2 BaZnO 5 near-infrared up-converting phosphors with organic photovoltaic devices is reported. We show that it is possible to obtain a J sc of 16 lA cm À2 under 986 nm illumination ($390 mW cm À2 corresponding to $37 suns) leading to an up-conversion external quantum efficiency (g UC EQE ) of 0.0052%. Through modification of the organic photovoltaic devices to incorporate transparent electrodes we show that g UC EQE could be increased to 0.031 %, matching that achieved in amorphous-Si:H PV cells. Accounting for the full spectral range that may be absorbed by the phosphor ($870-1030 nm) yields an up-conversion power conversion efficiency (g UC PCE ) of 0.073% which again could be improved to 0.45% using transparent electrodes. This technique for utilizing the near-infrared spectral region may therefore offer a potential route to improving the performance of organic photovoltaic devices as research into discovering high-efficiency up-converting phosphors continues to provide improved materials. V C 2012 American Institute of Physics.

A method for the synthesis of metal nanoparticles coatings for plasmonic solar cells which can meet large scale industrial demands is demonstrated. A UV pulsed laser is utilized to fabricate Au and Ag nanoparticles on the surface of polymer materials which forms the substrates for plasmonic organic photovoltaic devices. Control of the particles' size and density is demonstrated. The optical and electrical effects of these embedded particles on the power