161 |
Fine Line Metallization of Silicon Heterojunction Solar Cells via Collimated Aerosol Beam Direct WriteJanuary 2012 (has links)
Solar energy has come to the forefront as a scalable and largely underutilized renewable energy resource. The current cost of solar electricity, namely from photovoltaics, along with other logistics factors, has prevented the widespread adaptation of the technology. A key determinant of efficiency and cost for a solar cell is the current collector grid. This work presents the Collimated Aerosol Beam Direct Write (CAB-DW) system as a non-contact printing method that can achieve current collector grid finger widths of less than 10 μm which are amenable to decreasing both resistive and optical losses. The ability to produce high aspect ratio grid fingers, and deposit optimized grid structures on high efficiency SHJ solar cells using silver nanoparticle inks is also demonstrated. A decrease in shadowing and via profile modification of the grid fingers is presented, along with a study of aging and degradation of electrical properties within silver nanoparticle inks.
|
162 |
An investigation of chemically-sprayed-CdS films and solar cells.January 1980 (has links)
by Chow Lap-wai. / Thesis (M.A.)--Chinese University of Hong Kong, 1980. / Bibliography: leaves 185-188.
|
163 |
Fabrication technology of CIGS thin film solar cells on flexible substrates. / 柔性襯底銅銦鎵硒太陽能電池製備工藝 / CUHK electronic theses & dissertations collection / Fabrication technology of CIGS thin film solar cells on flexible substrates. / Rou xing chen di tong yin jia xi tai yang neng dian chi zhi bei gong yiJanuary 2013 (has links)
Ma, Xuhang = 柔性襯底銅銦鎵硒太陽能電池製備工藝 / 馬續航. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 88-91). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Ma, Xuhang = Rou xing chen di tong yin jia xi tai yang neng dian chi zhi bei gong yi / Ma Xuhang.
|
164 |
Study of polymer solar cells. / 聚合物太陽能電池研究 / CUHK electronic theses & dissertations collection / Study of polymer solar cells. / Ju he wu tai yang neng dian chi yan jiuJanuary 2012 (has links)
在這個對可再生能源需求不斷增加的新時代,聚合物太陽能電池成為其中一個最熱門的研究題目。在過去十年,聚合物太陽能電池的研究大多集中在液體處理的塊材異質接面結構。與傳統的‘雙層’結構比較,塊材異質接面結構提供一個更大的給體-受體界面面積讓電荷分離及減少電荷重組,從而帶來更高的能量轉換效率。目前使用塊材異質接面結構的聚合物太陽能電池最高能量轉換效率約為8 %。最近在文獻中公佈的一篇文章中,聲稱‘雙層’器件也可以達到與塊材異質接面器件媲美的高效率。這類‘雙層’器件採用相連沉積的給體層P3HT 和以二氯甲烷作溶劑的受體層PCBM 製作。然而,也有報告指在熱退火處理下PCBM 會擴散進入P3HT 的非晶區從而堤高能量轉換效率。我的工作是研究這類所謂的‘雙層’系統。藉運用紫外-可見光光譜儀和掠角X 光繞射,對埰用不同處理手法的純P3HT 薄膜的聚集和結晶性能進行研究。結果發現P3HT 的聚集和結晶性能可能沒有直接的相關性。同時也發現通過縮短底層P3HT 溶劑的揮發時間,這類液體鑄型‘雙層’器件的能量轉換效率得以提高。通過加熱P3HT 薄膜來加快變乾的速度,可以造具較低聚集度和較高結晶密度的P3HT 層。比起常規P3HT 薄膜可以提高能量轉換效率大約15 %。同時也對重量比為1:1 的複合P3HT:PCBM 薄膜的聚集和結晶性能進行了研究。實驗結果進一步表明P3HT 的聚集和結晶性能可能沒有直接的相關性。雖然實驗未有充分運用所有其他可能的處理方法和物理参數對器件進行全面優化,但這項研究卻為液體鑄型雙層聚合物太陽能電池開闢一條新的優化路線。 / In this new age with increasing demand of renewable energy sources, organic solar cell (OSC) has become one of the most intense research topics. The major attention of research in OSC was given to the solution-processed bulk heterojunction (BHJ) architecture during the past ten years. Compared to traditional ‘bilayer’ architecture, the BHJ structure provides a greater donor-accepter interface area for charge separation and reduced recombination, which leads to a higher power conversion efficiency (PCE). The highest PCE reported using BHJ was about 8 %. In a recent article published in the literature, it was claimed that ‘bilayer’ devices can also achieve a high efficiency comparable to that for BHJ devices. Such ‘bilayer’ devices were fabricated by sequential deposition of the donor P3HT and acceptor PCBM layers using dichlormethane as the solvent of PCBM. However, it was also reported that the PCBM could diffuse into the amorphous regions of P3HT during thermal annealing to cause the efficiency enhancement. My work is to study such so-called ‘bilayer’ system. By using UV-Visible spectrophotometer and grazing incidence XRD, the aggregation and crystallization properties of the pure P3HT films fabricated using different processing methods were studied. It was found that the P3HT aggregation may not have direct correlations with crystallinity. It is also discovered that the PCE of such solution-cast bilayer devices are increased by shortening the evaporation time of the underlying P3HT layer from a solution. By heating the P3HT film to accelerate its drying, a less aggregated P3HT layer with a higher density of crystallites could be obtained. The PCE could be enhanced by about 15 % over that using a regular P3HT film. The aggregation and crystallization properties of the composite P3HT:PCBM films with a ratio of 1:1 by weight were also studied. The experimental results further indicate that the P3HT aggregation may not have direct correlations with crystallinity. Although the devices have not been fully optimized by exhausting all the other possible processing and physical parameters, this study opens up a new route to optimize solution-cast bilayer polymer solar cells. / Detailed summary in vernacular field only. / Wong, Man Kwong = 聚合物太陽能電池研究 / 王文廣. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Wong, Man Kwong = Ju he wu tai yang neng dian chi yan jiu / Wang Wenguang. / Abstract --- p.I / 摘要 --- p.III / Acknowledgement --- p.VI / Chapter Chapter 1 --- Introduction to Organic Solar Cells --- p.1 / Chapter 1-1 --- The history of the development of solar cells --- p.1 / Chapter 1-2 --- Motivation of developing polymer solar cells --- p.2 / Chapter 1-3 --- The materials used in polymer solar cells --- p.4 / Chapter 1-4 --- Basic working principles of the polymer solar cells --- p.6 / Chapter 1-5 --- Definition of some important parameters of solar cells --- p.8 / Chapter 1-5-1 --- Short circuit current density (J[subscript Ssubscript C]) --- p.8 / Chapter 1-5-2 --- Open circuit voltage (V[subscript Osubscript C]) --- p.9 / Chapter 1-5-3 --- Fill factor (FF) --- p.10 / Chapter 1-5-4 --- Power conversion efficiency (PCE) --- p.11 / Chapter 1-6 --- An outline of this thesis --- p.12 / Chapter Chapter 2 --- Experimental Procedures --- p.13 / Chapter 2-1 --- Common preparation procedures in all the experiments --- p.13 / Chapter 2-1-1 --- The cleaning of the glass and indium tin oxide (ITO) substrates --- p.13 / Chapter 2-1-2 --- The preparation of different donor and accepter solution --- p.13 / Chapter 2-1-3 --- The coating of PEDOT:PSS on the glass and ITO substrates --- p.14 / Chapter 2-1-4 --- The thermal vapor deposition of the cathode layer for solar cell devices --- p.14 / Chapter 2-2 --- The detailed experimental procedures of the active layers in different chapters --- p.15 / Chapter 2-2-1 --- Fabrication of the active layers in chapter 3 --- p.15 / Chapter 2-2-2 --- Fabrication of the active layers in chapter 4 --- p.17 / Chapter 2-2-3 --- Fabrication of the active layers in chapter 5 --- p.18 / Chapter 2-3 --- Measurement of the properties of the film samples and the performance of the solar cells --- p.19 / Chapter 2-4 --- Experimental errors --- p.20 / Chapter Chapter 3 --- A Survey on Polymer Solar Cells and Some Preliminary Works --- p.21 / Chapter 3-1 --- Traditional bilayer polymer solar cells --- p.21 / Chapter 3-2 --- Bulk heterojunction polymer solar cells --- p.22 / Chapter 3-3 --- Studies of thermal annealing effects --- p.26 / Chapter 3-4 --- Studies of solvent annealing effects --- p.28 / Chapter 3-5 --- Studies of the relationship between the thickness and the optical density of the films --- p.34 / Chapter 3-6 --- Solution-cast bilayer polymer solar cells --- p.35 / Chapter 3-7 --- Previous studies on solution-cast bilayer polymer solar cells --- p.39 / Chapter Chapter 4 --- Studies on Solution-Cast Bilayer Polymer Solar Cells --- p.42 / Chapter 4-1 --- Motivation and the basic ideas of my research work --- p.42 / Chapter 4-2 --- Higher PCE through the use of a low pressure environment of film formation --- p.43 / Chapter 4-3 --- Higher J[subscript Ssubscript C] through the use of chloroform as the P3HT solvent --- p.46 / Chapter 4-4 --- Higher PCE through the use of a pre-dried heating process --- p.52 / Chapter 4-5 --- Dependence of the device performances on the pre-dried heating temperature --- p.55 / Chapter 4-6 --- Effect of a small amount of PCBM in the underlying P3HT layer --- p.59 / Chapter 4-7 --- Short summaries --- p.62 / Chapter Chapter 5 --- Studies on P3HT:PCBM Blend Layers --- p.64 / Chapter 5-1 --- Motivation --- p.64 / Chapter 5-2 --- Effects on the P3HT aggregation and crystallization of the P3HT:PCBM blend layers due to different treatments --- p.64 / Chapter 5-3 --- Studies of the effects of the removal of PCBM on the P3HT aggregation and crystallization in P3HT:PCBM blend layers --- p.67 / Chapter 5-4 --- Short summaries --- p.70 / Chapter Chapter 6 --- Conclusion --- p.71 / Chapter 6-1 --- Summaries of the research work --- p.71 / Chapter 6-2 --- Ideas for future studies --- p.72 / Bibliography --- p.74
|
165 |
Design of a Rooftop Photovoltaic Array for the George C. Gordon Library at Worcester Polytechnic Institute: Structural, Thermal, and Performance AnalysisMayer, Jamie Lynn 27 April 2010 (has links)
In 2009, WPI formed a Presidential Task Force to engage the WPI community in sustainability research, thought, and action. One of the Presidential Task Force's specific objectives is to improve campus environmental performance, which includes energy conservation. Several new buildings such as the Bartlett Center and East Hall have utilized new green building techniques and materials. Older buildings at WPI which were built before new green building techniques and materials were developed can be equipped with photovoltaic systems to reduce the environmental impact and increase clean energy use. This thesis presents a rooftop photovoltaic array design for the George C. Gordon library at WPI which is expected to produce over 27,000 kWh and offset over 56,000 lbs of carbon dioxide emissions annually. The materials science and engineering of the photovoltaic system components are an important part of the design process. Structural and thermal modeling of photovoltaic components during the initial phase of array design is critical to the success of the PV system and maximizing the energy from the system. This thesis presents how differences in photovoltaic materials and mounting systems result in changes in lifetime and reliability. Using common wind, ice, snow and hail loads for the Worcester, MA area ANSYSâ„¢ structural simulations show that an attached mounting system is more structurally stable than a ballasted system. Using local weather data and thermal cycling, ANSYSâ„¢ thermal simulations show that silicon PV modules outperform other technologies at lower temperatures while cadmium telluride PV modules outperform other technologies at higher temperatures. It is recommended that WPI install poly-silicon PV modules, such as Evergreen Solar PV modules, to maximize power output.
|
166 |
Utilization of metal oxide cathode interfacial layer on donor/acceptor solar cells. / CUHK electronic theses & dissertations collectionJanuary 2011 (has links)
Wang, Mingdong. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
|
167 |
AESCU-BIKE design, implementation and testingRomero Suarez, Ivan Jesus January 2019 (has links)
The AESCU-BIKE project is a cargo bike which has an inbuilt off-grid photovoltaic and a monitoring system. The off-grid photovoltaic system consists of a PV module, a lithium-ion battery, a lead acid battery, a charge controller and an electrical fridge. The PV module produces electrical energy which is used to cover the demand of an electrical fridge to supply enough cooling to store and transport pharmaceutical at temperature ranges between 0 °C and 8 °C within the city of Ulm. The monitoring system acquires, saves and plot information regarding the performance of the AESCU-BIKE such as voltages, currents, irradiance, temperatures, location and speed. The first aim is to theoretically estimate the performance of the off-grid photovoltaic system during summertime and verify that the off-grid photovoltaics system components match. The second aim is to experimentally verify the theoretical estimation of the off-grid photovoltaic system performance during summertime by designing and implementing a monitoring system. The third aim is to visualize in real time information regarding the performance of the AESCU-BIKE. This information is used for an instant analysis of both transportation quality and correct functionality of the off-grid photovoltaic system. A user interface is programmed by using the software Nodered which can be installed in any smart device such as a computer, a smartphone or a Raspberry Pi. Three different tests are performed to experimentally verify the theorical estimation of the off-grid photovoltaic system performance during summertime. Information such as PV module electrical energy production, fridge electrical energy demand, fridge temperature, ambient temperature, location and speed are plotted and analyzed using the software Excel. After the results analysis, it is concluded that the monitoring system provides essential information to validate theoretical estimations and to deeply understand the behavior of the off-grid photovoltaic system. Regarding the PV module electrical energy production, losses related to the lack of a MPPT, not optimal PV module inclination angle and shading effect are clearly understood. Regarding the fridge electrical power demand, it is shown that the energy demand is highly related with the ambient temperature. The user interface makes the entire system more friendly. The instant visualization of the measurements helps the user to relate the physical phenomena with the system behavior.
|
168 |
Solvent and Substituent Effects on the Redox Potentials of Several Substituted TetraphenylporphyrinsRansdell, Robert Arthur 01 January 1991 (has links)
Tetraphenylporphyrins can be used to absorb visible light and pass on their excitation energy to electron transfer agents. The purpose of this research has been to investigate our ability to understand and control the energetics of porphyrin derivatives in order to use their electron transfer ability to harness the energy of sunlight. Shifts in the redox (reduction and oxidation) potentials of tetraphenylporphyrins result from variations in the substituents attached at the para- position of the phenyl rings of tetraphenylporphyrins, as well as variations in the state of ionization of those substituents, and the solvent in which the reactions are carried out. To measure the effect these variations, results from cyclic voltammetric experiments were plotted versus literature values of Hammett substituent constants to confirm the validity of linear free energy relationships as a model of substituent effects. Solvent effects on reduction potentials were correlated using experimentally determined values of the empirical solvent parameter ET. Some specific conclusions are summarized. 1. The usefulness of linear free energy relationships in correlating variations in redox potentials with changes in substituent was confirmed with two exceptions. Two of the porphyrins were shown to undergo a different electrochemical oxidation mechanism than the remaining porphyrins, and another porphyrin was shown to be more difficult to reduce than predicted on the basis of its substituent constant. 2. Solvent effects, here investigated as the effect of added water on the reduction potential of tetraaminophenylporphyrin in DMSO, were demonstrated to correlate with the Dimroth-Reichardt solvent parameter, ET , determined experimentally for each water-DMSO mix. 3. Variations in the state of ionization of ionizable substituents such as carboxylic acid, amine, and hydroxyl substituents were shown to affect porphyrin electrochemistry mostly through the protonation of bulk, solution-phase porphyrin by added proton donor. An additional effect of added proton donor was noted in an alteration in the mechanism of reduction to include some of a different mechanism wherein reduced porphyrin is protonated in a chemical equilibrium and then further reduced electrochemically.
|
169 |
Synthesis and photosensitizing properties of sublimable rhenium diimine complexesWong, Hei-ling. January 2007 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
|
170 |
Spherical Silicon for Photovoltaic Application: Material, Modeling, and DevicesGharghi, Majid January 2008 (has links)
Detailed material characterization of spherical silicon is conducted for the first time. Experimental results on crystallinity, impurities, and structural defects are presented to investigate the effect of growth mechanism and processing of the spheres.
Based on the material properties, the spherical bulk is characterized from electronic point of view. A model is developed to interpret photoconductivity decay measurements and extract minority carrier lifetime, the most influential parameter in device performance. The model includes the spherical geometry as well as the radial profile of carrier lifetime and the measurement results are used to characterize the quality of the spheres and the effectiveness of the process steps.
To analyze and predict the performance of spherical cells, a three dimensional opto-electric model is developed. The model separately treats the optical generation and carrier collection and is able to calculate the spectral response and the device characteristics. A simulation tool is created based on this model. The simulation results are of great importance in designing novel structures and optimizing fabrication processes.
The necessary characterization methodologies are developed to measure the spectral response and I-Vcharacteristics of individual cells, as well as an array consisting of several cells.
A new device design with passivated selective emitter is proposed based on simulation results. Plasma processes were developed to selectively etch back the deep emitter of the spherical cells using reactive ion etching, and then passivate the surface using plasma enhanced chemical vapor deposition of silicon nitride. The improvement in characteristics of the fabricated device is characterized using the developed measurement setups.
Industrial up-scaling and manufacturability of the proposed devices and processes are also discussed.
|
Page generated in 0.0522 seconds