The numerical solution of partial differential equations requires suitable boundary conditions. Based on a fundamental integral relation for Legendre polynomials, Marshak type boundary conditions are derived that can be applied if an expansion in Legendre polynomials is utilized to solve the spatially inhomogeneous kinetic equation of the electrons in gas discharge plasmas. In particular, it is now possible to relate directly the expansion coefficients of the phase space distribution with macroscopic quantities at the boundaries. That is, a well-defined influx or a reflection of electrons can easily be treated on the microscopic level.

Outlined here is a technique for sub-wavelength infrared surface imaging performed using a phase matched optical parametric oscillator laser and an atomic force microscope as the detection mechanism. The technique uses a novel surface excitation illumination approach to perform simultaneously chemical mapping and AFM topography imaging with an image resolution of 200 nm. This method was demonstrated by imaging polystyrene micro-structures.

In this paper, the fabrication and characterisation of pentacene-based photoconductors using indium tin oxide electrodes obtained by ion beam sputtering are discussed. The photoelectric properties of pentacene under red (632 nm) and ultraviolet (365 nm) illuminations were investigated. We have shown that the photocurrent was dependent on the wavelength, bias voltage and illumination side of the device. Moreover, we have demonstrated with transparent electrodes that the top contact configuration yields better performance compared to the bottom contact configuration. We obtained a maximum photoconductivity gain of approximately 3 × 103 and a faster dynamic response when the photoconductor with top contact geometry was illuminated with ultraviolet light from the semiconductor side (top illumination), with a photoconductivity estimated at 10-4  $\Omega^{-1}$  cm-1.

The Raman and FT-IR spectra of 3,5-dimethoxybenzyl alcohol (L1OH) were measured experimentally, and density functional theory (DFT) method were used to calculate the equilibrium geometry and vibration frequencies of L1OH for the first time. The results showed that the calculated frequencies agree well with the experimental ones. Potential energy distribution of each frequency was worked out by normal mode analysis. Thereafter a detail assignment of the vibrational frequencies of L1OH has been obtained.

The LiLax Co0.20 -x Ni0.80O2, where x = 0.00, 0.01, 0.03, 0.05 and 0.10 cathode materials for rechargeable lithium ion batteries were synthesized by simple sol-gel technique using aqueous solutions of metal nitrates and polyvinyl alcohol. The gel precursors were dried in vacuum oven for 12 h at 120 °C. After drying, the gel precursors were ground and heated at 800 °C. The structural characterization was carried out by X-ray powder diffraction. The sample exhibited a well-defined hexagonal layered structure. Surface morphology and particle size of the synthesized materials was determined by scanning electron microscope and transmittance electron microscope and it was found that the cathode materials consisted of highly-ordered single crystalline particles with layered structure. Electrochemical properties were characterized by the assembled test cells using galvanostatic charge/discharge studies which were carried out at a current rate 0.1 C at potential range of 2.75 to 4.5 V. Among them, lanthanum doped LiLa0.03Co0.17Ni0.80O2 has improved the structural stability, high reversible capacity and excellent electrochemical performance of rechargeable lithium batteries.

Preparation of highly oriented layers of organic semiconductor – dithienothiophene derivative is described. The layers were obtained by zone-casting technique – a solution based one step method that does not require the use of preoriented substrates. Unidirectional alignment of the dithienothiophene derivative molecules in the zone-cast layers was confirmed by absorption and photoluminescence polarized spectra. Anisotropy of electrical properties was characterised by means of anisotropy of charge carrier mobility in field effect transistors (FETs). The FET devices were fabricated in bottom contacts – bottom gate configuration with the channel lengths parallel and perpendicular to the crystal growth direction, respectively. The FET mobility determined in the direction parallel to the zone-casting direction is ca. 1 order of magnitude higher than those in the perpendicular direction.

Cd1 -x Sbx S films (x = 0.0, 0.1 and 0.2) were deposited by the ultrasonic spray pyrolysis method. The films were deposited on glass substrates at temperatures of 300 °C. The effect of antimony doping on the structural and vibrational (FT-IR and Raman) properties of cadmium sulphide films were examined. Structural investigations of the films showed the hexagonal polycrystalline structure and that the incorporation of antimony leads to substantial changes in the structural characteristics of CdS films. The preferential orientation of the Cd1 -x Sbx S films shifts from (002) to (101) with increasing x values. The Raman spectrum for CdS films is dominated by an intense band at 301.5 cm-1(1LO) assigned to the first-order longitudinal optic phonon and the second-order phonon peak 598.5 cm-1 (2LO). Cd1 -x Sbx S films have been prepared and their FT-IR (400-4000 cm-1) spectra are reported for the first time. The vibrations at 550-1164 cm-1 are caused by Cd-S and C-O stretching vibrations.

The thin-film technology is the most promising technology to achieve a significant cost reduction in solar electricity. Laser scribing is an important step to preserve high efficiency of photovoltaic devices on large areas. The high-repetition-rate laser with the pulse duration of 10 ps was applied in selective ablation of multilayer thin-film a-Si solar cells deposited on flexible and rigid substrates. Two types of solar cells with flexible and rigid substrates have been investigated. The first type of solar cells was made of 400 nm a-Si layer coated on both sides with 2  $\mu $ m transparent ZnO:Al contact layers deposited by CVD technique on the glass plate. The second type of solar cells was made of a flexible polyimide substrate coated with the Al back-contact, a-Si light absorbing layer and the ITO top-contact. Selection of the right laser wavelength is important to keep the energy coupling in a well defined volume at the interlayer interface. Well-defined shapes of scribes were produced by laser ablation through layers of the solar cell on the glass substrate. Localization of the coupled energy at the inner interface led to the “lift-off” type process rather than evaporation of the top ITO layer when the 355 nm radiation was applied. All laser scribes did not indicate any material melting or other thermal damage caused by laser irradiation. Ultra-short picosecond pulses ensured the high energy input rate into absorbing material therefore peeling of the layers had no influence on the remaining material.

The characteristics of organic light-emitting devices based on aluminum tris-(8-hydroxy-quinoline) (Alq3), N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) with novel p-isopropenyl-calix[8]arenestyrene copolymer buffer layer and Al cathode were investigated. The devices with TPD/Alq3/Al were also fabricated in the same way for comparison. The p-isopropenylcalix[8]arenestyrene copolymer used as buffer layer greatly improved the performance of the device and increased the device efficiency and stability.

Nanocomposite organic-inorganic dye-sensitised solar cells have been constructed by using solution processed materials that are easily deposited, they do not necessitate sealing or encapsulation and offer satisfactory efficiency. The main components of the cell are a nanocrystalline titania layer made of commercial Degussa P25 and a solid gel electrolyte made of a ureasil precursor. Details on cell construction are given and show that the whole procedure can be upscaled for massive production.

Undoped and Al and In doped ZnO films were deposited on flexible PET substrates by Reactive Pulsed Laser Deposition (R-PLD). The morphological and structural characteristics of the obtained structures were investigated by AFM, SEM and XRD respectively. The transmittance spectra were recorded in the 300–1200 nm wavelength range and the electrical conductivity was measured. The samples appeared as granular and polycrystalline with high transparency and had a good electrical conductivity. The crystallinity of the undoped ZnO films improved with increasing pressure of the reactive oxygen gas. Doping of ZnO with Al or In modified the energy band gap and the resistivity of the material. The possibility for the application of such structures for the development of hybrid photovoltaic cells on flexible substrates will be demonstrated.