Sharif Digital Repository

Perovskite solar cells with 25.5% efficiency and fast and cheap manufacturing process are among the most promising technologies in this field to replace silicon cells. Despite the challenges of stability and toxicity to these cells, their manufacturing technology has recently shifted to the development of large-scale manufacturing methods in module dimensions. In the present study, the fabrication of perovskite cells in large dimensions to achieve the perovskite module has been aimed and studied that to achieve this, the method of large-scale spraying and printing using the vacuum system was used to create cell-forming films and, consequently, to make the final cell and module. To... 

In recent years, organo-metal perovskite solar cells have attracted remarkable attention due to their low cost manufacturing method as well as the rapid growth of efficiency. Despite the fast growing efficiency of organo-metal perovskite solar cells, there are big challenges around their low stability under real operational condition. In addition to extrinsic parameters like oxygen and humidity, intrinsic instability of perovskite rises mainly from ion migration in perovskite film. In order to understand the ion migration and its effect on photovoltaic parameters of the devices, appropriate characterizations and analysis are needed. Since ions are much slower compare to electrons, their... 

By the use of flexible substrates like metal foils and meshes and plastic ones, fabrication of flexible dye sensitized solar cells are possible. Flexible dye sensitized solar cell, not only is utilized in portable, light electronic devices, but is also conductive to industrial roll to roll fabrication which enables the implementation of high throughput production lines and its associated potential reduction in manufacturing costs. This thesis has concentrated on fabrication of flexible dye sensitized solar cells by use of stainless steel mesh as substrate of photo-anode, because of its satisfying stability in electrolyte, flexibility, transparency and low cost. In this research, an efficient... 

Copper-based semiconductors have received a great deal of attention due to their high absorption coefficient, direct and adjustable energy gap with stoichiometry, low frequency and toxicity. Multicomponent nanocrystals such as CuInS2, Cu (In, Ga) (S, Se) 2, Cu2ZnSnS4 and Cu2SnS3 (CTS) have been successfully synthesized by colloidal synthesis and have shown application potentials such as energy conversion, photocatalyst, thermoelectric and biomedical. Among these, the CTS ternary semiconductor with p-type conduction is one of the most well-known compounds of group I-IV-VI, which consists of abundant and non-toxic elements. In this research, thin-film solar cells with FTO / TiO2 / In2S3 / CdS... 

In this research, the technology of fabrication and deposition of nanoparticle inks from chalcogenide compounds and then use of them in the fabrication of CuInGaS2 and Perovskite thin-film solar cells have been considered. In the first step, the synthesis of CuInGaS2 family compounds with variable In / Ga ratio and also the change of the stoichiometric ratio of Cu component using oleylamine solvent is investigated. In addition to these compounds, the synthesis of CuSnS, CuBaSnS, and CuZnSnS nanoparticles is also investigated. The synthesized nanoparticles were analyzed by XRD, DLS, UV-Vis, ICP, PL, SEM, EDX, and TEM. Then, the stability of the ink made of CuInGaS2 nanoparticles in different... 

Zinc oxide is a wide band gap semiconductor material with wide applications as conductive oxides used in electro-optical devices. Thin films of doped zinc oxide (e.g. Al:ZnO, B:ZnO) are already used in thin-film solar cell technologies as electrodes. Chemical bath deposition (CBD) is a promising method for fabricating transparent and conductive ZnO layers at low temperatures (<100 °C) on nonconductive and temperature-sensitive substrates. Having a natural crystal habit, ZnO readily grows rod-like arrays when grown in an aqueous solution by CBD, posing challenges when attempting to deposit dense and conductive layers. The purpose of this study was to deposit dense and conductive zinc oxide... 

The use of renewable energy sources has received much attention due to the increasing need for energy, limited energy resources and the pollution of fossil fuels. Among all types of solar energy conversion technology, photovoltaics has the highest technical potential and Iran’s geographical location is very suitable for benefiting from this energy. So, in this thesis, the fabrication and characterization of nanostructured solar cells based on organic-inorganic perovskites have been investigated. Many research goups have tried to increase the efficiency of perovskite solar cells. The efficiency of this kind of solar cells depends mainly on the light-absorbing layer (perovskite) and its... 

Perovskite solar cells have attracted much attention due to their high photovoltaic performance. The excellent performance of perovskite solar cells is attributed to the superior electrical properties of each layer, including the electron-transporting layer, the light-absorbing layer, and the hole-transporting layer. The electron transport layer plays a key role in influencing the photovoltaic parameters of perovskite solar cells. SnO2 is considered as an ideal electron transport layer for perovskite solar cells due to its high carrier mobility, deep conduction band, suitable band gap and low temperature processing. Surface modification of SnO2 has significantly improved device performance... 

The aim of this thesis was to study and fabricate stable inks of Cu2SnS3 (CTS), Cu2ZnSnS4 (CZTS) and Cu3SbS4 (CAS) copper-based chalcogenide nanoparticles (NPs) and their application in solar cells. Inorganic semiconductors with p-type conductivity, high stability, high hole mobility (compared to organic type), and the ability to synthesize and deposition by simple low temperature solution-based methods have the potential to provide suitable alternative for hole-transporting material (HTM) in perovskite solar cells (PSCs) and the photo-absorbers in thin film solar cells (TFSCs). The ability to adjust energy levels and optoelectrical properties is another advantage of these compounds. In... 

In this research we focus on study and fabrication of ordered nanotube arrays of titanium oxide and their applications in photoelectrochemical cell. Nanotubular films of titanium oxide have been fabricated using anodization method. Short-length nanotubes, less than one micrometer, have been synthesized in aqueous electrolyte containing deionized water, hydrofluoric acid and phosphoric acid. To get Micron-length nanotubes, we have employed organic electrolyte containing ethylene glycol, deionized water and fluoride ammonium. After fabrication, the photo-catalytic activity of nanotubular structures was evaluated by measuring the rate of degradation of in methylene blue aqueous solution. The... 

Power harvesters are used to generate energy for electronic devices. These electrical energy generators consist of three main parts: energy source, power electronic converter and energy storage. In order to minimize some of the weaknesses of these devices, including low power density and low reliability, the hybrid power harvesting method can be utilized. In this thesis, we design and build a hybrid energy harvester considering the advantages of simultaneous usage of solar and thermal energies for a wearable sensor, focusing on "efficiency enhancement" and "availability improvement". In the designed device, both solar and thermal energy harvesting units operate independently. In the solar... 

In just a decade, perovskite solar cells have emerged as the next generation of photovoltaic technologies due to their high efficiency, low manufacturing cost, and easy fabrication methods compared to silicon solar cells. To date, highly efficient perovskite cells (with an efficiency of approximately 25.5%) have been fabricated on small substrates by a spin-coating process. In the spin coating process, perovskite precursor is spread on the substrate through shear force. However, the reproducibility of the cells coated with this method varies between research laboratories. Furthermore, since the solution is wasted during the deposition of the perovskite precursor on large substrates, a... 

Hydrogen can serve as a green alternative to fossil fuels and contribute to improving environmental conditions. In this context, reducing the cost of hydrogen production is of fundamental importance. It is necessary to examine the impact of influential environmental parameters on hydrogen production cost reduction. In this study, a relationship for optimizing hydrogen production in two scenarios, with constant anode pressure and variable cathode pressure, as well as both variable anode and cathode pressures, has been presented. Furthermore, the effect of various parameters, including temperature, pressure, proton exchange membrane thickness, and solar cell efficiency, on hydrogen production... 

Hand-launched UAVs are type of unmanned aerial vehicles that due to transportability and geometric specification, are operationally valuable and worthy. reconnaissance & surveillance (aerial mapping, aerial filming, inspection, border protection); health care (blood transport, body organ transport, medicine delivery); agriculture (farm monitoring, fertilization, cloud seeding); payload delivery (envelopes posting); network covering (internet supply, telecommunication relay); crisis management (remote area medical) are some of typical applications and missions of this type of aircrafts. These UAVs have almost low altitude short endurance (below 5000 ft. and less than 2 hrs.). To extend their...