Integration of liquid crystals with redox electrolytes in dye-sensitised solar cells

This thesis examines the electro-optic, electric and electrochemical properties of liquid crystal (LC) materials in self-assembly systems, that is, liquid crystal-polymer electrolyte composites (LC-PEs), LC binary mixtures, and their potential application in dye-sensitised solar cells (DSSCs). The birefringence of LCs causes light modulation, which can be controlled by an applied voltage and electric field. In particular, the LCs are used as one of the components for the electrolyte redox couple which is responsible for charge transfer mechanism in DSSCs. In this work, LC-PEs were developed by dissolving LCs in polymer electrolytes; using a homologous series of cyanobiphenyls in a range of concentrations, alkyl chain lengths and dielectric permittivities. We found that doping the polymer electrolyte with 15% 4'-cyano-4'-pentylbiphenyl (5CB) improved ionic conductivity by up to 13 % compared to pure polymer electrolyte. Materials with positive dielectric permittivity and shorter alkyl chain length have been identified to be compatible with iodide/triiodide (I^-/I_3^-)-based polymer electrolytes. In DSSCs, 15% 5CB and 15% E7 LC-PEs exhibited the best efficiencies of 3.6 % and 4.0 %, respectively. In addition to LC-PEs, the self-assembly properties of smectic phase LCs were also utilised as templates for controlling the polymer structure in polymer electrolytes. A porous polymer network was prepared using various techniques including self-assembly, by applying an electric field and using a polyimide (PI) alignment layer. We found that the electrochemical and photovoltaic properties of these materials strongly correlated to the morphology/structure with the self-assembled structure, thus showing the best photovoltaic performance (5.9 %) even when compared with a reference solar cell (4.97 %). Finally, this thesis explores the interaction of LCs with graphene (Gr) in DSSC device architectures. Gr-based DSSCs were fabricated using different processing conditions, with the result being that Gr improved the performance of the DSSCs. The highest efficiency obtained was 5.48 % compared to the 4.86 % of a reference DSSC. The incorporation of LC-PEs in Gr-based DSSCs improved the performance of DSSCs was observed in devices with low concentrations of LCs due to the Gr inducing planar alignment of LCs. These results suggest a new strategy to improve DSSC efficiency by incorporating LC materials in the polymer electrolyte component. Even though these LCs are highly insulating, their self-assembly and dielectric polarisability help enhance ionic conductivity and optical scattering when doped into polymer electrolytes. This work can be extended in a fundamental way to elucidate the ionic conduction mechanism of LC-based electrolyte systems. Furthermore, it would be interesting if the benefits of using LC-PEs and smectic-templated polymer electrolytes (Sm-Pes) can be translated further in commercial electrochemical energy conversion systems

Characteristics of grounding performance at Taman Bukit Perdana

Grounding system is one of the important part during installation of power systems. The function of grounding system is to enable protection to the power system in case of any current leakage or lightning strike. A grounding system will disconnect the circuit as soon as the fault current flows through the earth [1]. Every potential connection or equipment that may cause the current leakage must be grounded. In a simple way, it can be defined as the system to protect and stabilize the operation for human and equipment during fault conditions

Smart distribution board overload detector by using microcontroller

A statistic by Economic Planning Unit (EPU) on the electricity growth in Malaysia has shown an increment in line with economic growth [1]. In line with government policies, the energy supply industry has been molding itself to cater to the rapid development of the nation in hopes of creating a better and smarter nation [2]. There are many developments and implementation of smart energy consumption to save energy and cater to future energy challenges

Collapsibility behaviour of ABS P400 and PMMA used as sacrificial pattern in direct investment casting process

The feasibility of the Investment Casting (IC) process has been choose to be vital route in producing the metal alloy products. However, less report regarding the feasibility of portable Additive Manufacturing (AM) machines to be employed in casting process. Sacrificial wax pattern in casting process has been substitute with the AM material due to its brittleness and higher cost for hard tooling. Due to this constrain, the quality of fabricated AM materials, collapsibility analysis and strain induce was investigated. The patterns were made using ABS P400 and PMMA materials by two different types of technique which are Fused Filament Fabrication (FFF) and Polyjet technique. There were three different types of internal structures which are hollow, square and hexagon patterns. The thermal properties of the materials were studied by thermogravimetry analyzer (TGA) and linear thermal expansion. The collapsibility screening was determined to investigate the behavior of the patterns underneath the expansion. Apparently, patterns made by Polyjet technique shows better accuracy compare to FFF technique. It shows that, the PMMA error lies between -2.2 % until -0.63 % compared to ABS which is -2.4 % until 1.2% for hollow, square and hexagon patterns respectively. The data of the surface roughness were varies whereas internal structures does not play significant role in improving the surface roughness. From the strain analysis, it can be suggested that hexagon internal structure yield less stress compare to square patterns. In terms of collapsibility, hollow and hexagon patterns yield most successful warping whereas it indicates the patterns able to collapse underneath the expansion. Moreover, PMMA material tends to gain higher strain compared to ABS material whereas this can be illustrated by the graph of linear expansion. Nevertheless, to overcome the cracking of ceramic shell due to higher thermal expansion, different build layer thickness was adopted to overcome the issue

Breakdown Characteristics of Unused Transformer Oil and Olive Oil under AC and DC Voltages at Different Temperature Rate

This project aim is to investigate the breakdown characteristics of unused transformer oil and olive oil under AC and DC voltage at different temperature rate. HVAC and HVDC breakdown tests are carried out alongside with the hemisphere electrode arrangements. The high voltage test is done in order to observe the performances of the oil samples to attain the highest breakdown AC and DC voltages. In addition, this project needs to be done to see if olive oil as one of the vegetable oil can be an alternative for the conventional transformer oil. Commonly used transformer oil is made from mineral oil and it is declining day by day as its use increases. So as a precaution studies are done with vegetable oils to replace the mineral oil-based transformer insulation fluid. In this study, each oil sample is tested at different temperature rate and has recorded different value of breakdown voltage from the experiment. The gap distance between electrodes is constant and oil samples are heated at different temperature ranges. More voltage is needed to breakdown at higher temperature rate. Both the unused transformer oil and olive oil have linearly increased AC and DC breakdown voltages when subjected to higher temperatures. However, it is found that the highest AC and DC breakdown voltages are recorded at the highest temperature range and when the insulating medium used is olive oil. Moreover, the obtained AC and DC voltages are then be used to study the electric field in FEMM softwar

Electric Field Characteristics of HDPE-NR Biocomposite Under Breakdown Condition

It is critical to develop new insulating materials that can improve the performance of next generation high voltage cables for creating future electrical networks. The high electric field reduces the resistance of solid insulation and produces partial discharge through imperfections in a dielectric, causing the dielectric to age and eventually fail. Thus, this project seeks to analyse the electric field intensity of High Density Polyethylene (HDPE) in breakdown condition when added with 10g, 20g and 30g of different types of bio-filler such as coconut coir fibre, pineapple leaves fibre, and oil palm empty fruit bunch. This can be achieved by creating a two-dimensional (2D) axisymmetric electrostatic model by using the Finite Element Method Magnetics (FEMM) 4.2 software. The results showed that the unfilled HDPE biocomposites have a higher electric field intensity than 10g, 20g, and 30g biocomposite. This indicates that the maximum electric field intensity changes according to the permittivity and voltage of the bio-filler under breakdown conditions. As a result, the maximum electric field intensity was much lower for HDPE added with a 20g of the pineapple leaves fibre. Hence, pineapple leaves fibre was the best composition as it tends to improve the dielectric properties since it has a lower electric field intensity at the top electrode as compared to other compositions

Addition Effect of Pyreneammonium Iodide to Methylammonium Lead Halide Perovskite‐2D/3D Heterostructured Perovskite with Enhanced Stability

Despite the eminent performance of the organometallic halide perovskite solar cells (PSCs), the poor stability for humidity and ultraviolet irradiation is still major problem for the commercialization of PSCs. Herein, a novel functional organic compound 1‐(ammonium acetyl)pyrene is successfully introduced for preparing the 2D/3D heterostructured MAPbI3 perovskite. Because of the functional organic pyrene group with high humidity resistance and strong absorption in the ultraviolet region, the 2D/3D perovskite film shows notable stability with no degradation in ≈60% relative humidity after even six months and exhibits a high ultraviolet irradiation stability which keeps nearly no degradation after 1 h in the UV Ozone treatment. Planar PSCs are fabricated in the ≈60% relative humidity air outside glovebox. The champion efficiency of (PEY2PbI4)0.02MAPbI3 perovskite solar cells is 14.7% with nearly no hysteresis which is equal performance of 3D MAPbI3 devices (15.0%). This work presents a new direction for enhancing the solar cells\u27 performance and stability by incorporating a functional organic aromatic compound into the perovskite layer

Electric Field Characteristics of HDPE-NR Biocomposite Under Breakdown Condition

It is critical to develop new insulating materials that can improve the performance of next generation high voltage cables for creating future electrical networks. The high electric field reduces the resistance of solid insulation and produces partial discharge through imperfections in a dielectric, causing the dielectric to age and eventually fail. Thus, this project seeks to analyse the electric field intensity of High Density Polyethylene (HDPE) in breakdown condition when added with 10g, 20g and 30g of different types of bio-filler such as coconut coir fibre, pineapple leaves fibre, and oil palm empty fruit bunch. This can be achieved by creating a two-dimensional (2D) axisymmetric electrostatic model by using the Finite Element Method Magnetics (FEMM) 4.2 software. The results showed that the unfilled HDPE biocomposites have a higher electric field intensity than 10g, 20g, and 30g biocomposite. This indicates that the maximum electric field intensity changes according to the permittivity and voltage of the bio-filler under breakdown conditions. As a result, the maximum electric field intensity was much lower for HDPE added with a 20g of the pineapple leaves fibre. Hence, pineapple leaves fibre was the best composition as it tends to improve the dielectric properties since it has a lower electric field intensity at the top electrode as compared to other compositions

Enhanced Crystallization by Methanol Additive in Antisolvent for Achieving High‐Quality MAPbI3 Perovskite Films in Humid Atmosphere

Perovskite solar cells have attracted considerable attention owing to their easy and low‐cost solution manufacturing process with high power conversion efficiency. However, the fabrication process is usually performed inside a glovebox to avoid moisture, as organometallic halide perovskites are easily dissolved in water. In this study, we propose a one‐step fabrication of high‐quality MAPbI3 perovskite films in around 50% relative humidity (RH) humid ambient air by using diethyl ether as an antisolvent and methanol as an additive into this antisolvent. Because of the presence of methanol, the water molecules can be efficiently removed from the gaps of the perovskite precursors and the perovskite film formation can be slightly controlled, leading to pinhole‐free and low roughness films. Concurrently, methanol can be used to tune the DMSO ratio in the intermediate perovskite phase to regulate perovskite formation. Planar solar cells fabricated by using this method exhibited the best efficiency of 16.4% with a reduced current density–voltage hysteresis. This efficiency value is approximately 160% higher than the devices fabrication by using only diethyl ether treatment. From the impedance measurement, it is also found that the recombination reaction is suppressed when the device is prepared with methanol additive in the antisolvent. This method presents a new path for controlling the growth and morphology of perovskite films in humid climates and laboratories with uncontrolled environments

Mixed Sn–Ge Perovskite for Enhanced Perovskite Solar Cell Performance in Air

Lead-based perovskite solar cells have gained ground in recent years, showing efficiency as high as 20%, which is on par with that of silicon solar cells. However, the toxicity of lead makes it a nonideal candidate for use in solar cells. Alternatively, tin-based perovskites have been proposed because of their nontoxic nature and abundance. Unfortunately, these solar cells suffer from low efficiency and stability. Here, we propose a new type of perovskite material based on mixed tin and germanium. The material showed a band gap around 1.4–1.5 eV as measured from photoacoustic spectroscopy, which is ideal from the perspective of solar cells. In a solar cell device with inverted planar structure, pure tin perovskite solar cell showed a moderate efficiency of 3.31%. With 5% doping of germanium into the perovskite, the efficiency improved up to 4.48% (6.90% after 72 h) when measured in air without encapsulation