Saudi Cultural Missions Theses & Dissertations
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Item Restricted Inclusion of Poly(N-isopropylacrylamide) Microgels into Inorganic-organic Hybrid Perovskite Solar Cells(University of Manchester, 2024-03-04) Alkhudhari, Osama Meshal A.; Saunders, Brian R.Solar cells have become increasingly substantial to our planet due to their providing us with green energy sources. Perovskite solar cells (PSCs) have been continuing to attract considerable attention owing to their excellent optical properties, band gap tunability, low cost, high efficiencies as well as their ability to be semitransparent, colourful, and flexible. Semitransparent perovskite solar cells (ST-PSCs) and colourful perovskite solar cells (C-PSCs) have become a point of interest to researchers around the world due to their versatile applications, including building integrated photovoltaics (BIPVs), such as roofs, facades and windows, and tandem solar cells. In this work, poly(N-isopropylacrylamide) microgel (PNP MGs) are introduced into the perovskite precursor solution in a one-step spin-coating deposition method for the first time. MGs are crosslinked polymer colloid particles that swell in a good solvent. The inclusion of PNP MGs into perovskites leads to the formation of highly ordered 2D non-close-packed particle arrays within the perovskite layer and control of the surface morphology. Additionally, the PNP MGs are used for the fabrication of ST-PSCs exhibiting great impact in improving both the power conversion efficiency (PCE) (11.64%) and average visible transmittance (AVT) (25.3%) for the MG-treated ST-PSCs compared to the control systems. In addition, The PNP MGs enhanced the light utilization efficiency (LUE) for the devices giving a value of 2.60% compared to 2.50% for the MG-free device. Finite difference time domain (FDTD) simulation data were used to support the experimental data, showing the effect of the MGs in improving the AVTs. The results suggest that the PNP MGs passivated the perovskite layer. Furthermore, in this work, colourful semitransparent perovskite solar cells (CST-PSCs) are fabricated by altering the contents of the PNP MGs. This approach results in the formation of structurally CST-PSCs that show colour in both reflected and transmitted geometries by scattering light. This occurs due to the non-hexagonal close-packed arrays within the MG-based perovskite films. The CST-PSCs exhibited a PCE of 10.60% and AVT of 25.52%. In this thesis, different compositions of perovskite are used, which are MAPb(I0.82Cl0.18)3, (MA0.39FA0.61Pb(I0.93Cl0.07)3, Cs0.05(FA0.98MA0.02)0.95Pb(I0.98Br0.02)3, and Cs0.12FA0.88Pb(I0.92Br0.08)3 (MA is methylammonium, and FA is formamidinium), which demonstrates the generality of this approach and good compatibility of the PNP MGs within perovskite. Thus, this PNP MG approach may provide a scalable potential technique for ST-PSCs and CST-PSCs applications as it offers a simple fabrication process that can be done using a one-step deposition method.12 0Item Restricted Solvation Dynamics of Choline Halide-Based Deep Eutectic Solvents(2023) Alfurayj, Ibrahim Ahmed; Burda, ClemensThe intermittent nature of renewable energy sources requires reliable and cheap long-term energy storage technologies. Redox flow batteries (RFBs) are reliable, scalable, and cost-efficient. Electrolytes are crucial for RFB's performance. Deep eutectic solvents (DESs) are a new class of ionic liquids with relatively cheap and easy synthesis. In addition, their properties are tunable, making DES an excellent candidate for many energy and industry applications. A DES mixture is created by combining hydrogen-bond acceptor (HBA) and donor (HBD) in a specified ratio, producing a mixture with a lower melting point than its constituent components. Varying the type and ratio of HBA results in tunning DES properties. Also, adding co-solvents, such as water, can provide further tunning to DES mixtures. This dissertation aims to study the potential of water addition, HBA choice, and the compositional variation to optimize the solvation dynamics and physicochemical properties of choline halide-based DESs. Besides the most famous Ethaline (choline chloride ChCl): ethylene glycol (EG), 1:2), we reported the first choline fluoride (ChF) and EG-based DES mixture preparation with 1:2 molar ratio. We studied physical properties upon water addition by conductivity, density, viscosity, and ET(30) polarity. NMR, FT-IR, and Raman spectroscopies were used to characterize their structures. Femtosecond transient-absorption spectroscopy (fs-TSA) and NMR-diffusometry were used to study solvation dynamics, providing a powerful tool for studying charge transport properties. Volumetric properties were used to study the effect of water in EthalineF/water and Ethaline/water mixtures. This work also investigated the eutectic enhancement of dynamics and charge transport in Ethaline. We provided excellent tools, such as using B30 as a probe molecule in time-resolved spectroscopy to study solvation dynamics and correlating DES-DES self-interactions to experimental conductivities. Also, proved that water (>1 wt.%) can accelerate charge transport and enhance physical properties. The vibrational spectroscopies indicate that EthalineF has stronger hydrogen bond interactions than Ethaline. In addition, we reported the effect of the solvodynamic radius on the observed lower conductivity in EthalineF compared to Ethaline. Furthermore, based on the NMR diffusion measurements, we assigned the two F-NMR peaks to be EG and choline associated fluorides.17 0