Flexible heterostructures based on metal phthalocyanines thin films obtained by MAPLE

Heterostructures based on zinc phthalocyanine (ZnPc), magnesium phthalocyanine (MgPc) and 5,10,15,20-tetra(4-pyrydil)21H,23H-porphine (TPyP) were deposited on ITO flexible substrates by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. Organic heterostructures containing (TPyP/ZnPc(MgPc)) stacked or (ZnPc(MgPc):TPyP) mixed layers were characterized by X-ray diffraction-XRD, photoluminescence-PL, UV–vis and FTIR spectroscopy. No chemical decomposition of the initial materials was observed. The investigated structures present a large spectral absorption in the visible range making them suitable for organic photovoltaics applications (OPV). Scanning electron microscopy-SEM and atomic force microscopy-AFM revealed morphologies typical for the films prepared by MAPLE. The current–voltage characteristics of the investigated structures, measured in dark and under light, present an improvement in the current value (∼3 order of magnitude larger) for the structure based on the mixed layer (Al/MgPc:TPyP/ITO) in comparison with the stacked layer (Al/MgPc//TPyP/ITO). A photogeneration process was evidenced in the case of structures Al/ZnPc:TPyP/ITO with mixed layers

Flexible organic heterostructures obtained by MAPLE

Organic heterostructures based on zinc phthalocyanine (ZnPc) and perylene tetracarboxylic dianhydride (PTCDA) were deposited by matrix-assisted pulsed laser evaporation (MAPLE) technique on conductive flexible substrate (ITO/PET) in three configurations: ZnPc/PTCDA (stacked layers), ZnPc:PTCDA (blend) and ZnPc/ZnPc:PTCDA/PTCDA. The effect of the configuration on the optical and electrical properties of the obtained heterostructures was investigated. For all heterostructures was observed an improved optical absorption in visible domain. The I–V characteristics recorded under illumination, revealed higher short circuit current (ISC) values for the ZnPc:PTCDA and ZnPc/ZnPc:PTCDA/PTCDA structures in comparison with that of the ZnPc/PTCDA structure. The results proved that by MAPLE can be obtained flexible organic heterostructures (in different configurations) with properties adequate for applications in flexible electronics and solar cell fields

Pulsed laser deposition method for fabrication of cds/tio2 and pbs photoelectrodes for solar energy application

Titanium films sputtered on FTO glass were used for obtaining highly oriented titania nanotubes via anodization technique. Then, pulsed laser deposition of CdS was carried out for sensitizing of similar to 60 nm wide titania nanotubes by applying 50, 100, 150 or 200 subsequent laser pulses. Scanning electron microscopy was used to indicate which samples had the open nanotubular structure of titania preserved after the deposition of CdS. Energy dispersive spectroscopy showed that a higher number of applied laser pulses results in the increase of Cd and S quantity within samples. Pulsed laser deposition technique was also employed for the fabrication of PbS counter electrode. I-V characteristics of the photovoltaic cells consisting the obtained electrodes were measured and compared under one-sun illumination. The photovoltaic cell with photoanode sensitized with CdS by applying 150 laser pulses showed the highest current density and voltage among the investigated cell

Organic heterostructures deposited by MAPLE on AZO substrate

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Precise femtosecond laser crater fabrication in hard nanolayered AlTiN/TiN coating on steel substrate

Processing of AlTiN/TiN multilayered hard coatings by femtosecond (fs) laser pulses has been investigated. Irradiation was performed in air with linearly polarized laser radiation with pulses of 200 fs duration at 775 nm wavelength. Single or 1000 subsequent laser pulses were directed at normal incidence towards target surface. Laser energy per pulse was adjusted from 0.5 to 50 mu J and corresponding fluence was 0.17-17.5 J cm(-2). The as deposited and laser-ablated samples were characterized by optical confocal microscopy, optical profilometry and scanning and transmition electron microscopy. In case of the AlTiN/TiN coating, a single-pulse damage threshold of 0.41 J cm(-2) was estimated. Well defined holes/craters with diameters from 7 to 35 mu m, up to 40 mu m depth were drilled, depending on laser pulse energy and number, after 1000 laser pulses. For small energy/fluence, laser induced periodical surface structures were observed. A model is discussed which can account for these features by the accumulation effect during multi-pulse irradiation. The forming craters can prove useful for fabrication of micron solid state lubricant reservoirs in the protective coating-steel system