Date of Award
Doctor of Philosophy (PhD)
Prof. Yousef Haik
Prof. Nacir Tit
Dr. Ahmad Ayesh
This study investigates the influence of nanoparticles (NPs) size on their optical properties, and the effect of combination of lead sulfide (PbS) quantum dots (QDs), with n-type and p-type NPs, on the photogenerated charge carriers transport across the heterojunction solar cell structure. PbS QDs, of a range of sizes, were synthesized using a co-precipitation process. In this study, p-type NPs, which are poly [3,4-ethylenedioxythiophene] –poly [styrenesulfonate] (PEDOT: PSS), copper oxide (CuO) and graphene oxide (GO); and n-type NPs which are zinc oxide (ZnO), titanium dioxide (TiO2), cadmium sulfide (CdS) and bismuth sulfide (Bi2S3), were synthesized and characterized by SEM and UV-visible spectrophotometers. The NPs with enhanced optical properties were utilized in heterojunction solar cell structures via spin coating, chemical bath deposition and SILAR cycle methods. The morphology and the theoretical band energy diagram for each cell were examined. The photovoltaic performance of the cells was measured in the dark and under 1 sun illumination (irradiation of 100 mW/cm2). This yielded cells with efficiencies from 0.388% up to 5.04%. The solar cell with FTO/ZnO/TiO2/CdS/PbS/PEDOT:PSS/Au structure and optimum layers' thickness exhibited a short-circuit current of 24.2 mA/cm2, an open circuit voltage of 544 mV, a fill factor of 38.2 % and a power conversion efficiency of 5.04% with good stability. This is related to the uniform surface morphology throughout every cell layer without voids, pinholes or cracks. Furthermore, the gradual band energy levels alignment of n-type and p-type QDs (CdS/PbS), as well as the high hole vii mobility of PEDOT:PSS and the high electron affinity of ZnO and TiO2 are other contributory factors influencing efficiency enhancement.
I would like to express my great appreciation to those who contributed directly or indirectly to my dissertation during the completion of this study. I am sincerely grateful to my supervisor Professor Yousef Haik for his continuous support, guidance, encouragement and fruitful discussions throughout this research. I appreciate the kind coopration and assistance of my co-advisors Professor Nacir Tit and Dr.Ahmad Ayesh whose assistance with theoretical, practical and logistical issues proved invaluable throughout the process of preparing this dissertation. I would like to thank the technical staff in the laboratories at the Mechanical Engineering Department and the Physics Department for their support on technical issues. I also appreciate the encouragement of all my friends who inspired me throughout my studies. Finally, I appreciate the support of my family, with special thanks to my husband Khalid for his understanding and unconditional support throughout this research.
Dagher, Sawsan Khader, "PbS QUANTUM DOT-BASED HETROJUNCTION SOLAR CELLS" (2014). Dissertations. 27.