Search results for "thin film"
showing 10 items of 1200 documents
Polymorphic chiral squaraine crystallites in textured thin films
2020
Chirality 32(5), 619 - 631 (2020). doi:10.1002/chir.23213
Energy level determination of purine containing blue light emitting organic compounds
2018
Organic light emitting diodes (OLED) have found their applications in the mobile and TV screens. Till now the commercially available diodes are made by expensive thermal evaporation in a vacuum. The costs of OLED fabrication could be decreased by applying low-cost wet casting methods, for example, spin-coating. In this work, we have studied a group of blue light emitting purine derivatives which could potentially be used in OLEDs. The advantage of these compounds is their ability to form amorphous thin films from solutions. All the thin films were prepared by the spincoating method from chloroform solution on ITO glass. The position of hole and electron transport energy levels is important …
Rayleigh-instability-driven dewetting of thin Au and Ag films on indium-tin-oxide surface under nanosecond laser irradiations
2013
Investigations have been carried out on laser-beam-induced nanoparticle (NP) formation in thin (5 nm) Au and Ag films on indium-tin-oxide substrate. After the irradiation the films were observed to break-up into NPs through a dewetting mechanism. This mechanism was investigated as a Rayleigh-instability- driven process. In fact, for each used laser fluence, the resulting Au and Ag NPs' mean size and surface-to-surface mean distance were quantified and correlated between them in the framework of the Rayleigh-instability theory showing an excellent agreement. © The Institution of Engineering and Technology 2013.
Nonlinear Absorption and Refraction of Picosecond and Femtosecond Pulses in HgTe Quantum Dot Films
2021
We report measurements of the saturated intensities, saturable absorption, and nonlinear refraction in 70-nm thick films containing 4 nm HgTe quantum dots. We demonstrate strong nonlinear refraction and saturable absorption in the thin films using tunable picosecond and femtosecond pulses. Studies were carried out using tunable laser pulses in the range of 400–1100 nm. A significant variation of the nonlinear refraction along this spectral range was demonstrated. The maximal values of the nonlinear absorption coefficients and nonlinear refractive indices determined within the studied wavelength range were −2.4 × 10−5 cm2 W−1 (in the case of 28 ps, 700 nm probe pulses) and −3 × 10−9 cm2 W−1 …
Selecting speed-dependent pathways for a programmable nanoscale texture at wet interfaces
2012
Review article: recommended reading list of early publications on atomic layer deposition - outcome of the "virtual Project on the History of ALD"
2017
Atomic layer deposition (ALD), a gas-phase thin film deposition technique based on repeated, self-terminating gas-solid reactions, has become the method of choice in semiconductor manufacturing and many other technological areas for depositing thin conformal inorganic material layers for various applications. ALD has been discovered and developed independently, at least twice, under different names: atomic layer epitaxy (ALE) and molecular layering. ALE, dating back to 1974 in Finland, has been commonly known as the origin of ALD, while work done since the 1960s in the Soviet Union under the name "molecular layering" (and sometimes other names) has remained much less known. The virtual proj…
Fabrication and Characterization of Dye-Sensitized Solar Cells
2014
Among the next-generation solar cells, a predominant role is played by Dye sensitized solar cells (DSSC) based on ruthenium complexes as sensitizers. They take advantage of a photoelectrochemical system to transform solar radiation into electric energy. In fact, DSSCs represent a cost-effective alternative to traditional silicon-based photovoltaic devices and they do not require expensive and sophisticated apparatus for their fabrication. In this work, we have produced and tested ruthenium DSSCs. In particular, we have measured the main parameters of these cells, such as the electrical and power performances and the efficiency levels, at different irradiance levels and at different incident…
Interfacial Engineering in Vacuum-Deposited Perovskite Solar Cells for Improved Performance and Space Stability
2021
Perovskite solar cells are an emerging technology that is evolving rapidly, with power conversion efficiency values that compete with traditional materials such as silicon. In this type of solar cells the photons are absorbed in the perovskite and the charges are extracted using transport materials. By sandwiching the perovskite between a material with and excess of negative (N) or positive (P) charge, one can fabricate a P-i-N or N-i-P structure depending on the deposition order of the materials. Perovskite solar cells have several advantages, mainly the possibility of being very thin thanks to the high absorption coefficient of the perovskite and the wide range of deposition techniques, c…
NANOWIRES AND THIN FILMS OF CIS/CIGS OBTAINED BY ELECTRODEPOSITION AS ABSORBER FOR SOLAR CELLS
2011
CuInSe2/Zn(S,O,OH) junction by electrochemical and chemical route for photovoltaic applications (GE 2014)
2014
Electrodeposition is a convenient technique for the development of low cost materials for photovoltaic (PV) device processing. Using a single step electrodeposition route, several groups have fabricated CIS (CuInSe) and CIGS (CuInGaSe) films. One of the most important requirements for successful application of one-step electrodeposition film formation is the ability to control composition of the deposited films and to develop polycrystalline microstructures with a low surface roughness and high sintered density.