Narrow Results

Several zinc(II) and aluminum(III) phthalocyanines substituted by carboxylic acid and sulfonic acid groups were anchored to nanocrystalline TiO₂ films. By irradiation with visible light the photovoltaic behavior of the electrodes containing LiI/LiI₃/propylene carbonate electrolyte was measured. Most efficient results were found using zinc(II) 2,9,16,23-tetracarboxyphthalocyanine, with a current conversion efficiency at 700 nm approaching 45%. It is shown that electron injection into TiO₂ occurs from the excited singlet state of the phthalocyanine derivatives. High stability of the cell performance under continuous irradiation was found.

A novel Four Switch Infinite Level Inverter (FSILI) is proposed in this paper. In conventional multilevel inverters, as the number of levels increases the output voltage becomes more sinusoidal. Unlike conventional multilevel topologies, the output voltage level in the proposed topology depends upon the switching frequency. Since the switching frequency is very high, the output voltage level approaches infinity, thus the name Infinite Level Inverter. Proposed topology requires only one inductor and capacitor reducing the size, weight and thus cost of the overall system. Inherent buck operation is happening in the proposed topology with a sine varying duty ratio PWM control. Steady-state analysis and design of the inverter are carried out. The proposed topology is simulated using Matlab/Simulink to evaluate the theoretical analysis and operation. A hardware prototype is also developed to validate the operation of proposed FSILI.

An analytic model of $J$–$V$ characteristics of photovoltaic devices based on quantum dot (QD) solids is developed. The model yields the upper estimation of the power conversion efficiency and predicts its extremal dependence on the diffusion length of excitons. The predictive power of our model is approved by the comparison with the experimental data for PbS QD-based solar cells.

Solar energy is one of the main resources in our modern life. Photovoltaic panels are one of the most important technologies that make use of solar energy good because the photovoltaic cells harvest light from the sun and turn sunlight into electrical energy. This paper presents the manufacture of the solar cell from (Al/ZnO/perovskite/CuO/$p$-Psi/Al) nanostructures using the drop-casting method at a 70°C process temperature. Perovskite (Cs₄CuSb₂${\mathrm{\text{Cl}}}_{12})$ nanostructures‘ structural, optical and morphological characteristics were identified by X-ray diffraction (XRD), SEM, UV–Vis spectrophotometer and AFM. This work generated a solar cell device with the highest energy conversion efficiency (12.49%) and filling factor of 33.7%, promising to create a high-quality polycrystalline crystal. In the current study, effective hybrid Pb-free Perovskite solar cells are explained and investigated.

The mathematically sound theory of quantum open systems, formulated in the ’70s and highlighted by the discovery of Gorini-Kossakowski-Lindblad-Sudarshan (GKLS) equation, found a wide range of applications in various branches of physics and chemistry, notably in the field of quantum information and quantum thermodynamics. However, it took 40 years before this formalism has been applied to explain correctly the operation principles of long existing energy transducers like photovoltaic, thermoelectric and fuel cells. This long path is briefly reviewed from the author’s perspective. Finally, the new, fully quantum model of chemical engine based on GKLS equation and applicable to fuel cells or replicators is outlined. The model illustrates the difficulty with an entirely quantum operational definition of work, comparable to the problem of quantum measurement.

The present work is to show the development of micropower systems or power MEMS characterized by thermal, electrical and mechanical power density 1~20 Watts in sub-centimeter-sized packages. Three kinds of typical micro power systems, namely, the micro-gas turbine engine, the MEMS rotary micro engine, and a micro thermoelectric system, are described in this paper. A novel microthermophotovoltaic (micro-TPV) system, which is being developed in NUS, is also introduced in this work. The system uses hydrogen as fuel and is able to deliver electrical power in the order of watts in a package less than 1 cubic centimeter in volume. The main components of the system are a heat source, a selective emitter, and a photovoltaic (PV) array. The performance of the system is largely affected by the materials of the emitter and the PV cells. When the emitter is made of Co/Ni-doped MgO, and the PV cells are made of GaSb, a 4.4 W electrical power output can be expected.