Excimer laser processing of inkjet-printed and sputter-deposited transparent conducting SnO2:Sb for flexible electronics

The feasibility of low-temperature fabrication of transparent electrode elements from thin films of antimony-doped tin oxide (SnO2:Sb, ATO) has been investigated via inkjet printing, rf magnetron sputtering and post-deposition excimer laser processing. Laser processing of thin films on both glass and plastic substrates was performed using a Lambda Physik 305i excimer laser, with fluences in the range 20–100 mJ cm− 2 reducing sheet resistance from as-deposited values by up to 3 orders of magnitude. This is consistent with TEM analysis of the films that shows a densification of the upper 200 nm of laser-processed regions

What are the Prospects of 3D Profiling Systems Applied to Firearms and Toolmark Identification?

This paper details a comparative pilot study of 3D (three dimensional) imaging technologies for potential application in forensic firearms and toolmark identification; as such it reviews the most up-to-date profiling systems. In particular, the paper focuses on the application of 3D imaging and recording technology as applied to firearm identification, being a specialised field within the discipline of toolmark identification. Each technology under test employs a different technique or scientific principle to capture topographic data i.e. focus-variation microscopy, confocal microscopy, point laser profilometry and vertical scanning interferometry. To qualitatively establish the capabilities and limitations of each technology investigated, standard reference samples were used and a set of specific operational criteria devised for successful application in this field. The reference standard crucially included and centred on was the National Institute of Standards and Technology (NIST) 'standard bullet'. This was to ensure that evaluation represented the practical examination of ballistic samples i.e. fired cartridge cases and bullets. It is concluded that focus-variation microscopy has potentially the most promising approach for a forensic laboratory instrument, in terms of functionality and 3D imaging performance, and is worthy of further investigation

Temperature dependent characteristics of La2O2S: Ln [Ln = Eu,Tb] with various Ln concentrations over 5-60 ºC

This research is aimed at developing an optical sensor for remotely measuring human skin temperature in electromagnetically hostile environments, such as within a magnetic resonance imaging (MRI) scanner. In this feasibility study, various concentrations of europium doped lanthanum oxysulphide (La2O2S: Eu- 0.1-15 mol % (m/o)) and terbium doped lanthanum oxysulphide (La2O2S: Tb - 0.005-50 m/o) have been investigated in terms of crystallinity, photoluminescent (PL) spectral and decay time characteristics. For both phosphors, X-ray diffraction (XRD) has shown that as dopancy increases, the (100) and (002) reflections merge and there is a reduction in the c-axis parameter as well as the crystallite size. Photoluminescent characterisation (337 nm excitation) has also shown a dependency to dopant concentration through variance of peak intensity. Temperature dependent decay time measurements were carried out over a low temperature range of 5 to 60 °C. Optimum brightness of these temperature dependent lines is achieved at concentrations of 1 and 10 m/o for La2O2S: Eu and La2O2S: Tb respectively. However, optimum temperature dependency is achieved at lower concentration for La2O2S: Eu, specifically at 0.1 m/o. In comparison to conventional phosphor temperature dependent characteristic, La2O2S: Tb showed an increase in decay time with respect to temperature for concentrations above 2 m/o

A new reactive sputtering technique for the low temperature deposition of transparent light emitting ZnS:Mn thin films

The temperature sensitive nature of the substrates used in the flexible displays market necessitates a low temperature deposition technique for processing them. ZnS:Mn exhibiting high intensity photoluminescence and good crystallinity has been deposited onto Si wafers, glass microscope slides and polymeric substrates using a new reactive sputtering technology referred to as HiTUS. This technique enables very high deposition rates and requires no substrate heating. When incorporated as part of a complete EL device, as-deposited ZnS:Mn films are seen to exhibit stable electroluminescence on Si, glass and planarised PET substrate materials. Post annealing of the devices on Si and glass at temperatures of up to 600 °C show that the HiTUS films perform better than equivalent ZnS:Mn films deposited using RF magnetron sputtering

Manufacturing of SIG Sauer 9 x 19 mm Pistols

This article details the manufacturing processes and assembly of 9 x 19 mm calibre SIG Sauer duty, sporting and limited edition pistols produced at the factory in Eckernforde, Germany. The principal manufacturing focus for this paper is SIG Sauer barrel production, as two methods of rifling are utilized in their pistols; electrochemical rifling and cold hammer forged rifling. However, pistol slide and frame manufacturing is also discussed, as well as assembly, proofing and test firing of firearms before sale

Numerical classification of curvilinear structures for the identification of pistol barrels

This paper demonstrates a numerical pattern recognition method applied to curvilinear image structures. These structures are extracted from physical cross-sections of cast internal pistol barrel surfaces. Variations in structure arise from gun design and manufacturing method providing a basis for discrimination and identification. Binarised curvilinear land transition images are processed with fast Fourier transform on which principal component analysis is performed. One-way analysis of variance (95 % confidence interval) concludes significant differentiation between 11 barrel manufacturers when calculating weighted Euclidean distance between any trio of land transitions and an average land transition for each barrel in the database. The proposed methodology is therefore a promising novel approach for the classification and identification of firearms

Selective modification of nanoparticle arrays by laser-induced self assembly (MONA-LISA): putting control into bottom-up plasmonic nanostructuring

Nano-structuring of metals is one of the greatest challenges for the future of plasmonic and photonic devices. Such a technological challenge calls for the development of ultra-fast, high-throughput and low-cost fabrication techniques. Laser processing, accounts for the aforementioned properties, representing an unrivalled tool towards the anticipated arrival of modules based in metallic nanostructures, with an extra advantage: the ease of scalability. In the present work we take advantage of the ability to tune the laser wavelength to either match the absorption spectral profile of the metal or to be resonant with the plasma oscillation frequency, and demonstrate the utilization of different optical absorption mechanisms that are size-selective and enable the fabrication of pre-determined patterns of metal nanostructures. Thus, we overcome the greatest challenge of Laser Induced Self Assembly by combining simultaneously large-scale character with atomic-scale precision. The proposed process can serve as a platform that will stimulate further progress towards the engineering of plasmonic devices

Efficient P3HT:PCBM bulk heterojunction organic solar cells; effect of post deposition thermal treatment

Organic solar cells based on P3HT:PCBM bulk heterojunction were prepared and subjected to post annealing at different temperatures (100, 120, 140, 160 and 180 °C). SEM, AFM as well as optical images have revealed that post deposition heat treatment has induced significant phase segregation between P3HT and PCBM which were found to result in growth of PCBM clusters on the films surface. The P3HT:PCBM absorption spectra were found to be blue shifted by 7 nm in films subjected to heat treatment at 160 °C and 180 °C. XRD data show a single diffraction peak at 2θ = 5.33 ± 0.23o for P3HT:PCBM films and was attributed to the edge-on arrangement of the (100) plane. Space charge limited conduction theory was employed to determine the charge carrier mobility; the highest obtained mobility was obtained for devices with active layers heat-treated at 140 °C. The change in the barrier height was derived from dark I–V. The variation in the metal–semiconductor contact between the Al electrode and P3HT:PCBM active layer were addressed and the barrier height has increased to form hole blocking contact and the ideality factor has decreased implying a decrease in the recombination rate. A direct relation between Fermi level, Vbi, and Voc was studied. Efficient device performance was ascribed to P3HT:PCBM layers which were subjected to post deposition heat treatment at 140 °C with PCE = 5.5 %, FF = 65.6 %, Jsc = 12.9 mA cm−2 and Voc = 0.65 V