Proceedings, MSVSCC 2015

The Virginia Modeling, Analysis and Simulation Center (VMASC) of Old Dominion University hosted the 2015 Modeling, Simulation, & Visualization Student capstone Conference on April 16th. The Capstone Conference features students in Modeling and Simulation, undergraduates and graduate degree programs, and fields from many colleges and/or universities. Students present their research to an audience of fellow students, faculty, judges, and other distinguished guests. For the students, these presentations afford them the opportunity to impart their innovative research to members of the M&S community from academic, industry, and government backgrounds. Also participating in the conference are faculty and judges who have volunteered their time to impart direct support to their students’ research, facilitate the various conference tracks, serve as judges for each of the tracks, and provide overall assistance to this conference. 2015 marks the ninth year of the VMASC Capstone Conference for Modeling, Simulation and Visualization. This year our conference attracted a number of fine student written papers and presentations, resulting in a total of 51 research works that were presented. This year’s conference had record attendance thanks to the support from the various different departments at Old Dominion University, other local Universities, and the United States Military Academy, at West Point. We greatly appreciated all of the work and energy that has gone into this year’s conference, it truly was a highly collaborative effort that has resulted in a very successful symposium for the M&S community and all of those involved. Below you will find a brief summary of the best papers and best presentations with some simple statistics of the overall conference contribution. Followed by that is a table of contents that breaks down by conference track category with a copy of each included body of work. Thank you again for your time and your contribution as this conference is designed to continuously evolve and adapt to better suit the authors and M&S supporters. Dr.Yuzhong Shen Graduate Program Director, MSVE Capstone Conference Chair John ShullGraduate Student, MSVE Capstone Conference Student Chai

Indium-free transparent conductive oxides for improved solar cell performance and reliability

The rising adoption of solar cells worldwide necessitates reducing solar cell costs, enhancing cell efficiency, and long-term module reliability. New solar cell architectures such as silicon heterojunction (HJT) and thin-film technology like an organic solar cell, perovskite, III-V, copper indium gallium selenide (CIGS), etc. are actively being investigated. The majority of them implement a transparent conductive oxide (TCO), predominantly indium tin oxide (ITO), in their device structure. With the rising cost and depleting indium reserves, it is essential to find alternatives. This thesis focuses on developing and analysing indium-free TCOs fabricated using atomic layer deposition (ALD) and explores various applications of TCOs for solar cells. It begins with a detailed examination of the evolving relevant literature, followed by a detailed description of the techniques used throughout the thesis. ALD grown ZnO based TCO is studied. Firstly, a DFT analysis of various dopants of ZnO is presented. Subsequently, Zr doped ZnO is fabricated, characterized, and implemented as an electron selective layer for organic photovoltaic cells (OPV). The introduction of Zr as a dopant increased electron mobility and a reduction of sheet resistance. This was translated into an OPV device which demonstrated an increase in 1% abs efficiency due to increased carrier collection. Graphene is a promising TCO due to its high conductivity and transparency. Unfortunately, the transfer process hinders its implementation in a solar cell as a top or bottom contact. In this work, the first transfer-free method was developed by growing graphene directly onto an ALD-grown functional layer (NiOx). It will be shown that the NiOx layer gets partially reduced to Ni by carbon, which subsequently catalysis the graphene growth. Potential induced degradation (PID) has once again become a major reliability issue for solar manufacturers. But the determination and identification of PID before module fabrication is still a challenge. This work presents a novel method to provide accelerated lamination free PID testing at a solar cell level. This method was validated by implementing it on cells from different manufacturers. In addition, this novel method was used to test the effectiveness of ALD films, mainly ZnO and Al-doped ZnO (AZO), to prevent PID at a solar cell device level. It will be shown that the addition of a 5 nm TCO thin film can prevent the Na diffusion into the solar cell, thus protecting the cell from PID. Finally, the techno-economic analysis of ALD TCOs for solar cells is presented. It was shown that with the current tools in the market and indium costs, ALD based TCOs are an economical alternative. Furthermore, a Levelized costs of electricity (LCOE) study on the ALD capping layer demonstrated a >1% improvement in LCOE, suggesting that PID prevention using ALD capping layer is technologically and economically advantageous