Theoretical studies of the temperature distribution during laser heating of the TiO2 precursor film on the FTO/glass substrate have been carried out. The simulation was performed on the basis of a numerical solution of the heat equation in the Matlab program to determine the energy density of the laser radiation necessary for crystallization of TiO2. It was shown that on the surface of the TiO2 precursor the temperature reaches a maximum value at a time point of 133 ns with the Gaussian temporal form of the laser pulse. The optimum energy density for crystallization of the TiO2 precursor film with the nanosecond pulse duration is 1.3-1.6 J/cm2, when the film thickness temperature corresponds to 400-500 °C. The obtained results of the simulation are consistent with experimental studies.
Keywords: numerical simulation, laser heating, temperature distribution, TiO2 film, solar cell
In this paper, the temperature distribution from a point source of heat under convective heat transfer is studied. The Navier-Stokes equation describing the steady two-dimensional laminar motion of a fluid is solved numerically. The distribution of the temperature field of a heat-loaded point source is obtained under appropriate boundary conditions, supplemented by the boundary conditions for the flow velocity to equal zero on the paraboloid walls by numerical integration using the control volume method.
Keywords: Radiator protrusion shape, thermal conductivity, thermal apparatus mode, the temperature of the heat source
TiO2 thin films are widely used as a transparent layer n-type conductivity in the perovskite solar cells. Nanocrystalline TiO2 films were deposited on the surface of glass substrates coated with tin oxide with fluorine (FTO) by spin-coating and subsequent laser annealing radiation with a wavelength of 1064 nm. The effect of laser annealing on grain size in the TiO2 film and spin-coating speeds on its thickness. It is found that the grain diameter in the resulting TiO2 films on average 17-64 nm at a power of laser annealing 30-70 W. It was found that the thickness of the TiO2 film is changed in the range of 72-124 nm spin-coating speed. Optimal parameters TiO2 thin film formed by laser annealing can enhance the efficiency of the perovskite solar cell.
Keywords: thin film, TiO2, centrifugation, laser annealing, surface morphology, thickness
Created single-stage model of silicon solar cell using PC1D v.5.9 program, designed to simulate the photovoltaic devices. In the process of simulation change the level of doping and thickness of the n + type layer of the front, as well as applied texturing the front surface. The influence of the doping level and the thickness of the n + type layer in the photovoltaic solar cell characteristics. It was determined that with the increase of the doping level and the thickness of the front n + -layer a decrease in the efficiency of solar cells. It was found that the use of texturing the front surface leads to an increase in efficiency and is associated with reduced reflection losses and an increase in the photocurrent.
Keywords: Silicon solar cell thickness, doping levels, texturing, current-voltage characteristic
Currently, laser annealing are widely used to create a polycrystalline silicon film, which is promising for use in thin film solar cell, and transistors, liquid crystal displays and sensors due to recrystallization of amorphous and nanocrystalline silicon films. The study of morphology and surface conductivity of single-crystal silicon film on a glass substrate by laser annealing power. Laser annealing is carried Nd: YAG laser with a wavelength of 532 nm, speed of movement of the stage with a specimen of 5 mm/s and a laser power ranging from 34 to 86 watts. The laser beam was focused on the sample in the form of a narrow line width of 10 microns and 60 mm in length. The dependence of the size of the nanocrystals and the conductivity of silicon films on the power of the laser annealing radiation. It is shown that the power of the laser radiation in the range of 60 to 70 W is optimal for the best electrical parameters silicon film for the purpose of its use in high-performance thin-film solar cells.
Keywords: silicon film, laser annealing, surface morphology, electrical conductivity, thin film solar cell
A numerical model of the laser annealing TiO2 film on the TCO / glass substrate with radiation of a wavelength of 1064nm (Nd: YAG laser) to the crystallization and its use in solar cells perovskite. The modeling used a numerical finite difference method for solving a system of one-dimensional unsteady heat conduction differential equations. As a result, laser annealing temperature distribution obtained in the process of modeling the structure of TiO2 / TCO / glass substrate by varying the laser power. It is shown that a high laser power (30-100 watts) is enough for an effective transition organometallic precursor of TiO2 in the crystalline phase of anatase TiO2 (transition temperature of 400-600 °C) for a short period of time (60 sec.) due to the direct absorption of photons laser radiation. It is found that for experimental studies should be used laser power of 30-70 watts, since a higher power (e.g., 100 W) raises the temperature of the substrate above its melting point (for example, for glass 650 ° C).
Keywords: Numerical modeling, laser annealing, TiO2 film, heat equation, solar cell
The paper analyzed the influence of the shape and projection of its location on the surface of the heat sink on the heat source temperature. Based on the theoretical analysis, it was shown that the pins, ribs, hinges, and other projections are present on the surface of the heat sink, it does not increase the cooling surface and heat-loaded lower temperature source. These designs provide only near the side surfaces of the rapidly decreasing dipole, quadrupole, and other components of the field, which are not conducive to heat dissipation from the source, and create a circulating flow.
Keywords: radiator protrusion shape, thermal conductivity, thermal apparatus mode, the temperature of the heat source