Saudi Cultural Missions Theses & Dissertations
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Item Restricted Semitransparent Poly(Vinylcaprolactam), PVCL, Perovskite Solar Cells(Saudi Digital Library, 2025) Alrubaysh, Othman; Saunders, BrianAmong the PV technologies perovskite solar cells (PSCs) have gained significant attention due to their power conversion efficiencies (PCEs) exceeding 27%, low production costs, and easy fabrication methods. A special type, semi-transparent perovskite solar cells (ST-PSCs), are especially promising because they can generate electricity while maintaining transparency, making them ideal for building-integrated photovoltaics (BIPVs), smart windows, and automotive applications. However, achieving high transparency, efficiency, and long-term stability remains a major challenge. To address this, researchers have used different strategies such as electrode optimization, optical engineering strategies, and additive engineering strategies. In this project, poly (N-vinylcaprolactam-co-acrylic acid) (PVCL-co-AAc) microgels (MGs) were introduced into different perovskites films to determine whether they can produce ST-PSCs. The PVCL-co-AAc MGs were first synthesised by precipitation polymerisation and characterised using dynamic light scattering (DLS) and scanning electron microscopy (SEM) to confirm the PVCL-co-AAc MGs sizes, their thermoresponsive behaviour, and stability. Then, PVCL-co-AAc MGs were incorporated within the perovskite precursor solution (DMF: DMSO 4:1). To investigate the effect of PVCL-co-AAc MGs on perovskite films, control films were first fabricated at different perovskite precursor concentrations to identify the optimal composition. Based on this, additional films were fabricated at the selected concentration with different PVCL-co-AAc MGs concentrations. All films were fabricated using a one-step spin-coating method and characterised by SEM, UV–Vis spectroscopy, photoluminescence (PL), and moisture stability tests to investigate the influence of MGs incorporation on the perovskite films. The results revealed that PVCL-co-AAc MGs films should uniform grain morphology and controlled nanopore formation. At optimal microgel concentrations 1–1.5 wt.% (PVK20-MG 1%, PVK20-MG 1.5%), PL intensity increased significantly, indicating few trap states and improved optical quality. Further, Average visible transmittance (AVT) values remained high (36–37%), confirming that transparency of PVK20-MG 1%, PVK20-MG 1.5% films was maintained. Stability analysis showed that control film (PVK20-CTRL) degraded to PbI₂ within five days, whereas PVCL-co-AAc MGs films (PVK20-MG 0.5%, PVK20-MG 1%, PVK20-MG 1.5%, PVK20-MG 3%) resisted degradation for longer, due to the hydrophilic acrylic acid groups, which slowed water penetration. The results indicate that incorporating PVCL-co-AAc MGs into perovskite films a promising approach for improving ST-PSCs and future work could focus on device-level studies to confirm their potential in practical photovoltaic applications.30 0Item Restricted Perovskite Solar Cells Incorporated with Processing Additives(The University of Akron, 2024) Sawwan, Hussain; Gong, XiongThe increased use of solar energy for power is anticipated to lead to the shift from traditional power sources to renewable energy sources. Photovoltaic (PV) is a promising technology due to its ability to directly convert sunlight into electricity with no pollution. Solar cells, specifically those based on metal halide perovskites (MHPs) have gained popularity recently due to their power conversion efficiency (PCE) that have increased dramatically over the past 15 years, from 3.8% to more than 26 %. The rapid development in PCE is due to the advanced features that MHPs have such as cost-effective and easy processing, high absorption coefficient, large diffusion length, and low exciton binding energy. In particular, the purpose of this study is to develop solution-processed perovskite solar cells (PSCs) by tuning film morphology and optoelectronic properties of metal halide perovskites incorporated with processing additives, thereby optimizing the performance of PSCs. To maximize the potential of perovskite, controllable crystallization is crucial for producing high-quality perovskite thin films with fewer structural defects and additive engineering is a facile and effective method among other techniques. We mainly investigated the effects of various processing additives on the MHPs based on MAPbI3 perovskite (where MA is CH3NH3) and correlate PCE in term of film morphology, crystallinity, photocurrent hysteresis, optoelectronic properties, device performance and stability of PSCs.25 0Item Restricted Interface and structural engineering of perovskite solar cells towards enhanced stability and performance(Saudi Digital Library, 2023-11-22) Almalki, Masaud; Graetzel, Michaelشهدت خلايا البيروفسكايت الشمسية تطورا سريعًا خلال العقد الأخير، حيث حققت كفاءة تنافس بالفعل أكثر تقنيات الخلايا الشمسية تأسيسًا واستخداما. تتميزهذه الخلايا بسهولة المعالجة وتتمتع بخصائص الكتروضوئية ممتازة تجعلها متاحة للعديد من التطبيقات في مجال الخلايا الشمسية والإلكترونيات البصرية. ومع ذلك، يكمن ضعف خلايا البيروفسكايت في ضعف استقرار أداها لفترة طويلة الذي يلزم لجعلها منتجاً تجاريًا. في هذه الرسالة، كنت أعمل على تحسين الاستقرار مستهدفًا مكونات مختلفة من هيكل خلايا البيروفسكايت بما في ذلك طبقة امتصاص ضوء الشمس ونقطة إلتقاص البيروفسكايت والطبقة الحاملة للشحنات الموجبة النتجة (p-type) في طبقة البيروفسكايت. وأخيرًا، استكشاف مواد جديدة والطبقة الحاملة للشحنات الموجبة النتجة (p-type) تحمل الإمكانية لتكون أكثر استقراراً مقارنة بالمواد المستخدمة حاليًا مثل spiro-OMeTAD. في الفصل الثاني تمت دراسة نوع من البيروفيسكايت يسمى البيروفسكايت المتدرجة Layered perovskite باستخدام الفينيلين-1،4-ديميثيل أمونيوم (PDMA) وتم استكشاف تركيبها على المستوى الذري. تم فحص الاستقرار هذي المواد في بيئات ذات رطوبة عالية مظهرا استقرارية هذا النظام في هذه الظروف والحصول على فهم أعمق لهذا النظام. في الفصل الثالث تمت معالجة سطح طبقة البيروفيسكايت بإيثيل أمونيوم يوديد (DEAI) حيث تم تحسين أداء الخلية الشمسية بكفاءة بنسبة 23.3% مع تحسين استقرار الخلية تحت الظروف التشغيلية والحرارية. في الفصل الرابع تم استخدام الغرافين أكسيد المطعم بالفلزات القلوية كطبقة حامية للبيروفسكايت، مما أسفر عن تحسين كفاءة تحويل الطاقة إلى 23.4%. أظهرت الخلايا الشمسية استقرارًا ممتازًا تحت الظروف التشغيلية والحرارية. وأخيرًا، في الفصل الخامس، تمت دراسة مواد جديدة (p-type)، مما أظهر أداءًا واعدًا. تم إجراء فحص شامل لخصائصها الإلكترونية والالكتروضوئية لتحديد العوامل الرئيسية المساهمة في فقدان الكفاءة، والتي تم العثور على أنها مرتبطة بتحسين نقطة التقاء سطح البيروفيسكايت مع طبقة (p-type) بدلاً من الخصائص الجوهرية لمواد (p-type)، أنفسها. يقدم هذا الفصل استراتيجية تحسين لهذه المواد الجديدة، مبرزًا إمكانياتها كبدائل لمواد (p-type) الحالية التي تمتاز بالفعالية العالية.32 0Item Restricted Improving The Performance and Stability of Perovskite Solar Cells Using Functionalised Microgels and Nanogels(The University of Manchester, 2023-09-07) Altujjar, Amal; Saunders, BrianPerovskite solar cells (PSCs) have excellent optoelectronic properties and provide high power conversion efficiency (PCE). However, the poor long-term stability hinders their commercialisation. This study investigates the effects of employing poly(2-(2-methoxyethoxy) ethyl methacrylate)-co-methacrylic acid-co-ethylenegylcol dimethacrylate P(MEO2MA-MAA-EGD) nanogels (NGs) and polystyrene microgels (MGs) in PSCs. MGs and NGs are colloidal dispersions of cross-linked polymer particles, and the difference in the name is based on the difference in the size which is much smaller for the NGs. The colloidal stability of these particles and their visibility by electron microscopy techniques make them good candidates for PSCs applications. The preparation and characterisation of P(MEO2MA-MAA-EGD) NGs and polystyrene MGs are investigated in this thesis. The P(MEO2MA-MAA-EGD) NGs are introduced to the perovskite precursor as additives for the first time in this study. The results reveal that the NGs act as a passivator, stabiliser, crosslinker and adhesion promoter. Therefore, the champion PSC containing NGs has an improved PCE to 20.2% and shows remarkable stability to ambient conditions for 6 months and to elevated temperatures for 240 h. On the other hand, hydrophobic and hydrophilic polystyrene MGs are incorporated as discontinuous interlayers at electron transport layer (ETL)/perovskite interface for the first time in this study. The findings illustrate that the nature and dimensions of these particles control ion migration, non-radiative recombination, and hysteresis of the respective devices. The champion PSC containing hydrophilic MGs discontinuous interlayer has an improved PCE to 20.1%, while PSCs having the hydrophobic MGs show the lowest non-radiative recombination, ion migration, and hysteresis. This study seeks to provide fundamental understanding of the mechanisms underpinning MG- and NG-based device enhancement and contributes to the improvement of the performance and stability of PSCs using facile, potentially low cost, and scalable strategies.12 0