Silicon Photocells Research Articles

Determination of the resistance of external parameters to the degradation of the parameters of silicon photocells with input nickel atoms

Currently, there is a growing need for high-performance photocells with increased stability of parameters to external influences, such as thermal and radiation resistance. This work is devoted to the study of photocells available in the volume of an ordered micro- and nanostructure based on silicon doped with impurity nickel atoms. The study of the formation of micro- and nanoclusters of impurity atoms in silicon photocells that were subjected to additional high-temperature processing makes it possible to determine the degradation of nickel clusters, which strongly affect the electrical parameters of photocells. It is shown that impurity nickel atoms will increase the stability of the electrophysical parameters of photocells under the influence of both high temperature and radiation. The results obtained in the study showed that the introduction of nickel impurity atoms into the volume of silicon-based photocells leads to temperature and radiation resistance, and also increases efficiency.

Gettering properties of nickel in silicon photocells

The effect of doping with nickel on the parameters of silicon photocells, in which the p-n- junction was created by impurities of III (B, Ga) and V (P, Sb) groups, has been studied. It is shown that the positive effect of nickel on the photocell efficiency does not depend on the type of initial silicon and on the nature of impurities used to obtain the p-n- junction, but is mainly determined by the gettering properties of the near-surface nickel-enriched layer Keywords: photocell, silicon, nickel, thermal annealing, clusters, lifetime, gettering, recombination centers.

Admittance spectra of silicon photocells: From dark mode to weak illuminate mode

The results of an experimental analysis of the admittance spectra structure in the frequency range of a harmonic test signal from 1 kHz to 10 MHz are presented. The signal amplitude did not exceed 20 mV, the surface density of the recorded photocurrent was limited to a value of 20 mA/cm2. Variants of PVC (Photovoltaic Cells) structural schemes in the dynamic approximation, optimal combinations of localized L, R, C parameters explaining the recorded spectra, dispersion characteristics, and Nyquist diagrams are discussed. A significant contribution of the inductive component in the PVC structural scheme is observed in both dark and weakly illuminated modes. The inductive component is associated with the current flow geometry, primarily with lateral currents. The screening effect in the p-n junction zone was noted at low illumination of the PVC surface; it manifests itself in the loss of the dependence of the admittance spectra on the bias voltage.

Admittance spectra of silicon photocells in dark mode

An extended model of silicon photovoltaic cells with localized parameters is presented, including inductance in a series branch. Based on the recorded admittance-frequency spectra, the dependences of the active and reactive components from the bias voltage for PERC (Passivated Emitter Rear Cell), HIT (Heterojunction with Intrinsic Thin-layer solar cells) and IBC (Interdigitated Back Contact cells) elements are reconstructed. The structure of the Nyquist diagrams for the components of admittance spectra is analyzed, which make it possible to visually determine the working scheme of the chain based on the elementary links of the first and second orders.

Геттерирующие свойства никеля в кремниевых фотоэлементах

Abstract: The effect of doping with nickel on the parameters of silicon photocells, in which the p – n junction was created by impurities of III (B, Ga) and V (P, Sb) groups, has been studied. It is shown that the positive effect of nickel on the photocell efficiency does not depend on the type of initial silicon and on the nature of impurities used to obtain the p – n junction, but is mainly determined by the gettering properties of the near-surface nickel-enriched layer

Автономный энергетический комплекс с ʌ - фотомодулями

The technology of converting solar radiation using innovative Ʌ-photomodules and a collector with an optical concentrator is considered. Silicon photocells generate a photocurrent and heat the intermediate heat carrier up to ≈ 650С, which releases thermal energy in the linear heat exchanger of the consumed water of the external circulation loop. Using experimental data on the characteristics of photovoltaic cells and double-sided collectors, a method for engineering calculation of the specific power of innovative Ʌ - photo modules was developed and computer modeling of the performance of cogeneration units was carried out.

Mean of Microaccelerations Estimate in the Small Spacecraft Internal Environment with the Use of Fuzzy Sets

Assessment of parameters of rotary motion of the small spacecraft around its center of mass and of microaccelerations using measurements of current from silicon photocells is carried out. At the same time there is a problem of interpretation of ambiguous telemetric data. Current from two opposite sides of the small spacecraft is significant. The mean of removal of such uncertainty is considered. It is based on an fuzzy set. As membership function it is offered to use a normality condition of the direction cosines. The example of uncertainty removal for a prototype of the Aist small spacecraft is given. The offered approach can significantly increase the accuracy of microaccelerations estimate when using measurements of current from silicon photocells.

Expansion of the spectral sensitivity range of the silicon photocells by growing a solid (Si2)1–x (GaP) x (0 ≤ x ≤ 1) solution

The article concerns the growth of a hetero-epitaxial GaP layer on a silicon substrate via a buffer layer containing a continuous solid substitutional solution (Si2)1–x (GaP) x (0 ≤ x ≤ 1) from the liquid phase. Epitaxial films grown under 950–830°С have n-type conductivity and specific resistance of ~0.01 Ohm•cm. The thickness of epitaxial films is 10–15 μm. The spectral sensitivity of the pSi-n(Si2)1–x (GaP) x (0 ≤ x ≤ 1) heterostructure, which allows expanding the region of the spectral sensitivity of silicon photoreceivers and photocells, is studied.

CALCULATION OF OPTIMUM PARAMETERS AND LIMIT CHARACTERISTICS OF CASCADE SILICON PHOTOCONVERTERS

Work is devoted to an assessment of optimum parameters of cascade silicon photo-electric converters. Unlike matrix solar elements the direction of a light stream is provided in cascade option perpendicular to the plane of several transitions created consistently on one basic plate of silicon. Follows from the analysis of constructive registration of the cascade photoconverter that the optimum mode of its work will be only when the solar light stream passing through basic layers of the semiconductor generates in them equal number of electron-hole couples in unit of time. This requirement can be realized by the corresponding calculation of extents of basic layers of the semiconductor. Thickness of high-alloyed layers n + and p + between basic layers have to be minimum and not exceed 0.5 microns everyone. Especially for determination of optimum values of basic layers in cascade silicon photoconverters settlement dependence of density of short circuit of silicon photo cells on semiconductor layer thickness at standard sunlight of AM-1.5 has importance. Calculations of optimum values of basic layers of cascade photoconverters are presented in work for two, three, four and five multitransitional structures. The analysis of parameters of multitransitional photoconverters allows to draw a conclusion that the considered semiconductor structures can be successfully used in devices of direct electrolysis of water on hydrogen and oxygen as the potential of such cascade photo cell lit with a sunlight considerably exceeds the potential of communication of atoms of hydrogen and oxygen in a water molecule. The same circumstance will help to take from sea water rich with minerals and other chemical elements which are of interest to certain industries and agriculture.

Non-fullerene acceptors for organic solar cells

Solar cells based on organic semiconductor molecules are a promising alternative to conventional silicon photocells owing to their low cost, simple production, and good mechanical properties. Effective organic photocells are based on a heterojunction using an active layer consisting of two different organic semiconductors, one of which is an electron donor, while the other is an acceptor. Progress in organic photovoltaics is related to the development of new donor materials, while fullerene derivatives are commonly used as acceptors. The advantages and disadvantages of fullerene compounds for organic solar cells are discussed in this review, the principles of their operation are briefly considered, and the most successful new non-fullerene acceptors are described. The application of latter acceptors has made it possible to fabricate organic solar cells with an efficiency of about 2–4%.

Thermophotovoltaics on the move to applications

Thermophotovoltaics (TPV) was intensively investigated as a technology for heat/electricity co-generation in the last decade of the 20th century. However, a wide-spread commercialisation has not been achieved yet. The world-record system efficiency for a TPV system using silicon photocells of 4% at 50W electrical output power as well as a maximum electrical output power of 164W, however at a lower efficiency of 0.84% could be demonstrated by a prototype system operating with an Yb2O3 selective emitter. Related developments of TPV system components such as radiation emitters, filters and photocells are reviewed and theoretical system simulations are compared to experimentally achieved results regarding system efficiency and the electrical output power. Finally, novel TPV applications are suggested and the commercial potential of this technology is discussed.

Artificial Light-Harvesting Arrays: Electronic Energy Migration and Trapping on a Sphere and between Spheres

A sophisticated model of the natural light-harvesting antenna has been devised by decorating a C(60) hexa-adduct with ten yellow and two blue boron dipyrromethene (Bodipy) dyes in such a way that the dyes retain their individuality and assist solubility of the fullerene. Unusually, the fullerene core is a poor electron acceptor and does not enter into light-induced electron-transfer reactions with the appended dyes, but ineffective electronic energy transfer from the excited-state dye to the C(60) residue competes with fluorescence from the yellow dye. Intraparticle electronic energy transfer from yellow to blue dyes can be followed by steady-state and time-resolved fluorescence spectroscopy and by excitation spectra for isolated C(60) nanoparticles dissolved in dioxane at 293 K and at 77 K. The decorated particles can be loaded into polymer films by spin coating from solution. In the dried film, efficient energy transfer occurs such that photons absorbed by the yellow dye are emitted by the blue dye. Films can also be prepared to contain C(60) nanoparticles loaded with the yellow Bodipy dye but lacking the blue dye and, under these circumstances, electronic energy migration occurs between yellow dyes appended to the same nanoparticle and, at higher loading, to dye molecules on nearby particles. Doping these latter polymer films with the mixed-dye nanoparticle coalesces these multifarious processes in a single system. Thus, long-range energy migration occurs among yellow dyes attached to different particles before trapping at a blue dye. In this respect, the film resembles the natural photosynthetic light-harvesting complexes, albeit at much reduced efficacy. The decorated nanoparticles sensitize amorphous silicon photocells.

Optimized Design of Sun Position Detection Sensor

With the object of optical sensor detects the position of the sun, the working principle of the sun position detection system based on four photosensitive devices was analyzed.The sensitive part of this type of sensors was analyzed with optimization. Silicon photocells were selected as optical elements . The main factors and interactions between them which affect the accuracy of the sensor were analyzed using the idea of orthogonal experiment and related software , the optimal combination for the size of the sensor structure was got.

Metal nanoparticles in acrylic polymer matrices

Methods are developed for the synthesis of metal nanoparticles (by the example of silver) in the matrices of acrylic polymer, namely, poly(methyl methacrylate) (PMMA) and poly-(2-hydroxyethyl methacrylate) (PHEMA). It is shown that the structure and physicochemical properties of the nanocomposites derived can be regulated by modifying the synthesis conditions. Investigation of the optical properties of the coatings based on the resulting nanomaterials allows a conclusion to be drawn about their possible application as an antireflection medium for silicon photocells.

Increase The Absorptive Capacity Of Light Of The Photocells By Embedded In Bow-tie Antenna

The application of silicon photocells has been widely used in biological and energy field, how to improve the efficiency of silicon photocells has become the research hot spots. The light absorption efficiency is not ideal, only 10% to 20% of solar energy can be transformed into electricity, the paper embeds metal bow-tie antenna in the crystals of silicon, by the field enhancement of the surface plasma, it highly increase the absorptive capacity of light of the silicon photocells.

The Structures for Controlling Charge Carriers in Silicon Photo Cells

The Structures for Controlling Charge Carriers in Silicon Photo Cells

Thermally affected parameters of the current–voltage characteristics of silicon photocell

The influence of temperature on the parameters of silicon photocells is presented. For comparison, the results of monocrystalline solar cells and photodiodes with a large light sensitive area are used. The temperature increase of the cell surfaces within the range from 22°C to 70°C as a function of illumination time has been observed. It is shown that the product I sc U oc degrades about 0.8% per 1 K temperature increase. In the paper, a small increase of the short circuit current, a significant reduction of the open circuit voltage and the electric power from the photovoltaic cells has been shown.

Characterisation of rare earth selective emitters for thermophotovoltaic applications

Abstract We investigate selective radiation emitters made from rare earth oxides suitable for thermophotovoltaic (TPV) systems. Yb 2 O 3 and Er 2 O 3 emitters were fabricated and their radiation power, temperature and emissivity were measured in the entire relevant spectral range. We found temperatures of 1735 K for the Yb 2 O 3 emitter and of 1680 K for the Er 2 O 3 emitter both heated with a 1.35 kW butane burner. The maximum emissivities of the selective peaks were 0.85 at 1.27 eV, and 0.82 at 0.80 eV for the Yb 2 O 3 and the Er 2 O 3 emitter, respectively. The emission spectra show gas emission lines originating from the combustion process in addition to the selective emission bands. An estimation based on a simplified combustion model show that a TPV system with a system efficiency of about 10% can be realised using an Yb 2 O 3 emitter, silicon photocells and a perfect selective filter.

Low-cost sensor integrators for measuring the transmissivity of complex canopies to photosynthetically active radiation

A system has been designed, tested and evaluated for measuring the transmissivities of complex canopies to photosynthetically active radiation (PAR). The system consists of filtered silicon photocells in cosine corrected mounts with outputs integrated by the use of chemical coulometers. The reading accumulated by the coulometers was taken electronically by the use of microcomputers. The low-cost sensor integrators, which do not require batteries, performed as expected and proved ideal for the study of agroforestry systems in remote areas. Information on the PAR transmissivity of a temperate agroforestry system in the form of an intercropped orchard is also presented.

Bulk minority carrier diffusion length and photogenerated carrier profile in silicon photovoltaic cells

The bulk minority carrier diffusion length of single-crystal and polycrystalline ribbon silicon photocells was measured with monochromatic light of various wavelengths and flux densities. We noted that the diffusion length shows a gradual reduction as the illumination wavelength becomes shorter in both types of cells. In addition, the light enhancement phenomenon of the diffusion length in the ribbon cells diminished when shorter wavelength lights were used. In the single-crystal cells, however, no enhancement effect was observed for any wavelength. The interpretation of these results is based on the examination of the photogenerated minority carrier profile as a function of diffusion length and wavelength in the bulk region of the cell. We correlate the measured diffusion length with the depth in which a positive minority carrier concentration gradient exists.