Advanced Materials Research Vols. 1070-1072

Abstract: To further shorten the charging time, enhancing charging efficiency and extending battery charge cycle life, this paper presents a variable frequency pulse fast charging methods based on fuzzy control depolarization. This method uses perturbation and observation method tracking resonant frequency real-timely and then finds the maximum current corresponding to the resonant frequency to charge the battery while using fuzzy control technology to detect and eliminate polarization effects arising from the charge process to accelerate the charging speed and realize frequency-varied fast charging. Experiments showed that using the fuzzy control frequency-varied pulse charging technique improves the charging time, charging efficiency, and rising temperature of the Li-ion battery by about 6.9%, 2.4%, 17.3%, respectively, as compared with the currently used fast charging method of intermittent alternating current.

Abstract: One of the valuable problems of modern science and technology is to create a low-power (less than 1 mW), long-life (10-100 years) miniature sources of electric power based on the conversion of radioactive isotopes of energy into electricity. Such batteries can be used directly, for example, in cardiology, microelectromechanical systems (MEMS), in military equipment and power sharing systems for many applications. Among isotopes to create energy sources particular interest is nickel Ni⁶³, as it is safe for human health and thus in the development of electric batteries based on it devoted a lot of work. This article discusses the main types of structures betavoltaic battery (BVB) with the prospects for industrial application using - isotope of nickel Ni⁶³. It is shown that the efficiency of beta radiation conversion of into electricity and the dimensions of the existing batteries are far from the theoretically possible. It is shown that the prospects for improving the effective efficiency are planar multijunction betavoltaic batteries.

Abstract: Commercial poly (vinylidene fluoride) (PVDF) films are uniaxially stretched with varying rates at 110 °C in order to endow PVDF piezo-and pyroelectric by crystalline-phase transition from α to β during the stretching. The crystalline phases are determined by infrared spectroscopy. The β-phase content and its fraction in films increase as a result of stretching with high rates. In addition, higher stretching rates yield a slight increase of γ phase. The crystallite size is evaluated by means of X-ray diffraction. It is found that the β-phase crystallites become smaller with fast stretching, whereas the α-phase crystallites are cracked and disappear at high-speed stretching of 2.5 /min.

Abstract: We theoretically investigate the thermoelectric properties of twisted armchair graphene nanoribbons (TAGNR) with various rotation angles. We find that the twist engineering applied to AGNR can alter the thermoelectric transport properties by modifying the electronic structures and phonon dispersion relations. With twist angle increasing , the thermal conductance tend to decrease, and the can tunable with different twist angle. Our calculation results suggests a possible route to increase the ZT values of AGNR-N for potential thermoelectric applications.

Abstract: The simulation of multicomponent nanoheterostructures (MNH) InGaN for light-emitting diodes (LEDs) was made. The results are presented in graphs, for example, the current-voltage characteristics, the dependence of the internal quantum efficiency (IQE) on the number of quantum wells (QW) and spectral characteristics. The optimal structure of the MNH and the influence of the inhomogeneous distribution of In atoms in the quantum-well region is investigated.

Abstract: With ammonia and hydrazine hydrate as complexing agents, ZnSe has been deposited as the buffer-window layer of solar cells from chemical solution, in which the complexion played vital role in controlling the film growth. We calculated various complexion in chemical solution deposited ZnSe precursor with solubility theory. And the main complexion and their concentration with adding of complexing agents and pH value have been investigated. And we found that the main complexion are Zn (NH₃)₃²⁺ and Zn (NH₃)₄²⁺, the concentration of which varied with the adding of ammonia and pH value.

Abstract: Quantum dot sensitized solar cell (QDSSC) has a potential high efficiency as the third generation solar cell, on account of the excellent performance of quantum dots. CdS is one of the most widely used quantum dot of QDSSCs, hence the optimization of its preparation process is extremely important. CdS quantum dots prepared in aqueous or alcohol on TiO₂ film by successive ionic layer adsorption and reaction (SILAR) method are investigated and alcohol is found to be better than water as the precursor solvent.

Abstract: Based on Density Functional Theory, we investigated electronic structure and optical properties of Cu vacancy doped SnO₂ with density of 4.35%, including the density of state(dos), the partial density of state(PDOS) and complex dielectric function. The results show that Fermi level access valence band with the increase of doped density. And this can attributed to the increased folded state. It has enhanced the electrical and metal property of material.

Abstract: The dye-sensitized solar cell performances influenced by radiant intensity and illuminated area in concentrating photovoltaic system are investigated experimentally and discussed theoretically. The results show that, under the same irradiated cells area, the short-circuit current is linearly increasing with the radiant intensity and the open-circuit voltage follows a logarithmic function of the radiant intensity. And, it is turned out that the short-circuit current and open-circuit voltage are obviously enhanced by increasing the illuminated cells surface area at the same radiant intensity. However, that growth trends will decline with an increase of the illuminated area. The reason is more defects involved in the process of increasing illumination area. All results can be interpreted using an equivalent circuit of a single diode model. A good agreement can be observed from the fitting curves. It is of great significance for current photovoltaic research.

Abstract: This article reports on photovoltaic performance and long-term stability of hybrid solar cells based on ZnO/TiOPc with DH-α6T as an electron blocking layer. When the thermal annealing temperature (T_A) was increased from 120 °C to 180 °C, these absorption spectra of TiOPc thin films reveal the gradual formation of the crystalline α-phase, as evidenced by the development of a red-shifted absorption band, peaking 845 nm, and the corresponding reduction of the 720 nm amorphous phase peak. Device performance of hybrid solar cells could be improved and open-circuit voltage (V_OC), short-circuit current (I_SC) and power conversion efficiency (η) were enhanced by thermal annealing, which originated from amorphous TiOPc films transformed into crystalline α-TiOPc films with a wider red and near-IR absorption band. At T_A = 150 °C, the device achieved the highest performance with V_OC, I_SC and η of 0.53 V, 1.71 mA/cm², and 0.29 %, respectively. Furthermore, the hybrid device showed long-term stability that this device maintained over 55 % of its initial η after 300 days aging at room temperature.