JULY 17-19, 2020


SESSION - I: Applied Physics

Abstract Number ANPA2020_0097
Author/s Tara Dhakal
Title Recent Progress in Thin Film Perovskite Solar Cells
Affiliation/s Binghamton University, Binghamton, USA
Abstract Perovskites are being extensively explored for both solar cells and lighting applications. To say that perovskites are wonder materials for the optoelectronic industry is an understatement. Generally, perovskites have a three-dimensional ABX3 structure (A: organic or inorganic cation, B: metal cation, X: halogen) in which self-organized two-dimensional (2D) planes of organic layers (AX) are sandwiched between 2D planes of inorganic halides (BX2). Organic-metal halide perovskites have shown remarkable improvement in recent years, with efficiencies increasing from 3.8% in 2009 to 25% in 2020, which is close to long-commercialized silicon solar cells. This presentation will cover a general overview of various solar cell technologies and a discussion on the recent progress in perovskite thin film solar cells. In addition, I will present my group’s work on the effect of buffer layers on both reliability and performance of the perovskite solar cells.

Abstract Number ANPA2020_0064
Author/s Rajesh Pathak, Qiquan Qiao
Title Artificial layer to suppress the lithium dendrite growth in lithium metal batteries
Affiliation/s South Dakota State University, USA
Abstract Cells based on Lithium (Li)-metal as an anode is of particular interest owing to their high energy density, and specific capacity more than ten times to that of graphite anodes. However, the notorious reactivity of Li-metal prevents their practical applications due to undesired Li dendrites growth and unstable solid electrolyte interphase (SEI) formation. Here, we consider a rational approach for designing an artificial Li-metal/electrolyte interface. Facile, cost-effective, and one-step reaction mechanism of pretreating Li metal anode with an electrolyte containing SnF2 was employed for the first time. As a result, an artificial SEI composed of LiF, Sn, and Sn-Li alloy was formed. The higher ionic conductivity and Young’s modulus of an artificial layer facilitate fast Li-ion diffusion and suppress the Li dendrite growth, respectively. An artificial SEI showed the synergistic effect of storing Li by forming reversible Sn-Li alloy and allowing Li plating underneath the SEI. Such protected Li symmetrical cells showed outstanding plating/stripping cycles with reduced overpotential compared to the bare Li. In addition, an artificial SEI protected Li anode coupled with high-loading (11.88 mg.cm-2) LiNi1/3Co1/3Mn1/3O2 (NMC111) showed remarkable results such as longer stable cycling, higher capacity at higher rates and higher rate capability compared to the bare Li anode. This approach could lead to the development of high energy density and safe Li-metal based batteries.

Abstract Number ANPA2020_0074
Author/s 1 Rupak Timalsina; Ryan O. Behunin; Danielle R. Havercamp
2 Nils.T.Otterstorm; Peter T. Rakich
Title Artificial layer to suppress the lithium dendrite growth in lithium metal batteries
Affiliation/s 1. Department of Applied Physics and Material Science, Northern Arizona University, Flagstaff, AZ,USA
2.Department of Applied physics, Yale University, New Haven, CT, USA
Abstract Abstract not displayed at Author's request

Focus Session - I: Physics Education Research

Abstract Number ANPA2020_0072
Author/s Rijendra Thapa
Title Assessment of effectiveness of virtual simulation for tutoring introductory level Physics based on the syllabus of Nepal Education Board (NEB)
Affiliation/s Kathmandu World School (KWS), USA
Abstract For past two years I have incorporated PHET simulation in guiding High School Students- both +2 (syllabus based on NEB) and Cambridge International A Level (CIAE). The discrepancy in the effectiveness on these two syllabus will be discussed with supporting evidences. In addition to it, I will discuss how teachers in Nepal can use virtual simulations in guiding students learn Introductory Level Physics effectively.

Abstract Number ANPA2020_0070
Author/s Ramesh Dhungana
Title Quantitative critical thinking with interactive labs
Affiliation/s University of Colorado, USA
Abstract "Traditionally introductory physics lab courses have been designed to reinforce the physics contents taught within the lecture courses. Laboratory manuals provide step by step instruction to verify physics laws learned in classroom. But some recent studies on students’ performance on final exam score have raised questions as to the effectiveness of such lab courses. I will talk about simplifying the traditional labs and making them interactive to achieve critical thinking skills that leads to discovery. I will share some example labs I have developed inspired from Cornell University. I will also talk how we are implementing such lab remotely. "

Abstract Number ANPA2020_0098
Author/s Bijay Aryal
Title Innovating Physics Instruction to Promote Student Learning of Skills
Affiliation/s University of Minnesota Rochester, USA
Abstract Educators and employers have identified student learning of transferable intellectual and practical skills as critical for academic success and the workforce of the twenty-first century. Robust and deliberate innovations are essential to change physics learning from a general trend of content-based acquisition towards promoting the learning of skills. In addition to building students’ scientific reasoning, the innovations must promote students’ competencies in non-routine problem solving, decision-making ability, critical thinking, and creativity as important educational goals. Systematic instruction of non-routine problem solving in physics courses can help students develop qualities such as patience and perseverance that have a wide range of applications. In this talk, I will describe instructional innovations aimed to promote student learning of skills. One of the innovative approaches facilitating student learning of skills is interdisciplinary curricular reform. Such reforms aim to improve student perceptions regarding the relevance of interdisciplinary subskills and foster students’ ability to identify integrated knowledge structure. The efforts value the importance of interdependence among physics and partner disciplines in the establishment of a common vocabulary. Interdisciplinary educational bases aim to promote learning environments to nurture the development of sophisticated epistemologies. Explicit instruction of both expert epistemologies and metacognitive techniques aim to support students in making interdisciplinary and metacognitive leaps to navigate the ambiguous and complex realities of various disciplinary fields. It is necessary to understand if and how interdisciplinary subskills interact over time and contexts affecting the transfer of learning. I will describe a web-based tool as an innovative physics problem solving instructional strategy. The system, known as Customizable Computer Coaches for Physics Online (C3PO), is written in Adobe Flash consisting of two graphical user interfaces (GUI). The cognitive apprenticeship model (Brown, Collins & Duguid, 1989) is the pedagogical framework of the system. The tool provides students individualized guidance and feedback in a non-intimidating environment. Students interact with the coaches by adjusting the pace of coaching that is suitable for their learning styles and capacities. Using a validated problem-solving rubric, I have assessed the effectiveness of the coaches on students’ problem-solving sophistication, problem-solving strategies, and decision-making ability. Student interviews and student surveys have provided feedback for the systematic improvements in software and pedagogical designs of the tool. A majority of the students who used the coaches have spontaneously resembled the coaches to the human coaches. Using the Theory of Planned Behavior (Azjen 1991), I have analyzed the factors affecting the student acceptance of the tool. Additionally, I have investigated how the acceptance of the tool affects the quality of student interaction with the tool and student learning of problem solving. Students tend to use the coaches at various degrees and ways depending on their confidence and expectations. This study revealed students’ views about learning and learning resources influence their expectations about the coaches. Analysis indicates that the students’ likability of the tool determines the usage patterns, which, in turn, determines students’ physics problem-solving competency.

Abstract Number ANPA2020_0099
Author/s Mahendra Thapa
Title Experiences of promoting equity and diversity in physics teaching & learning
Affiliation/s California State University, USA
Abstract Many research have indicated that innovative ideas and successful implementation of projects could be possible whenever an equitable and diversified environment flourish. Equity and diversity are playing key roles in teaching and learning communities. In the present talk, I will share my personal experiences of promoting equity and diversity through physics teaching and learning to fulfill the mission and vision of a community college. The techniques which I adopted are transferable to other disciplines and institutions as well with proper adjustment based on one's need to reduce achievement gaps. Students from low-income families , 1st generation college students, women and underrepresented students are the main beneficiary in terms of lower course drop rate, higher successful course completion rate and better course satisfaction.

Keynote Talk

Abstract Number ANPA2020_0100
Author/s Umeshwar Prasad Joshi
Title Our teachers and mentors: We owe them!
Affiliation/s Fermi National Accelerator Laboratory, USA

Session II: AMO/Plasma Physics

Abstract Number ANPA2020_0101
Author/s Tika R. Kafle(1,2), B. Kattel (1), P. Yao (1,3), H. Zhao (1), W. L. Chan (3)
Title Charge Transfer Exciton and Dissociation Dynamics at Organic - TMDC heterostructures
Affiliation/s (1) Department of Physics and Astronomy, University of Kansas, Lawrence, 66045
(2) JILA and Department of Physics, University of Colorado, Boulder, 80309
(3) Key Laboratory of Luminescence and Optical Information, Ministry of education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China
Abstract Over the past decade we have witnessed significant advances associated with the optical frequency comb technology occurred in a diverse range of scientific field. Compared to a conventional laser source, the most distinguishing feature of a femtosecond optical comb is that it provides a broadband laser source with well-defined phase coherence across the optical spectrum. This makes it a unique tool for spectroscopic applications, simultaneously providing high spectral resolution and broad spectral coverage. On this talk, I will discuss about production of the frequency comb as well its various application including trace-impurity detection in specialty gases, breath analysis for medical diagnosis, and precision measurement in atomic physics.

Abstract Number ANPA2020_0045
Author/s Madhav Dhital, Sujan Bastola(1), Aaron Silvus(1), Basu Lamichhane(1), Deni Cikota(1), Brendan Boggs(1), Jake Davis(1)
Ahmad Hasan(2)
Ramaz Lomsadze(3)
Don Madison(1), Esam Ali(1)
Marcelo Ciappina(4)
Michael Schulz(1)
Title Fully Differential Study of the Post-Collision Interaction in the Few-Body Dynamics of Simple Atomic Systems
Affiliation/s (1) Missouri University of Science and Technology, Rolla, Missouri, USA
(2) UAE University, Al Ain, Abu Dhabi, UAE
(3) Tbilisi State University, Tbilisi, Georgia
(4) Institute of Physics of the ASCR, ELI-Beamlines, Prague, Czech Republic
Abstract Advancing our understanding of the few-body problem is one of the important goals of atomic scattering research. It is very important to understand the relative contribution of first vs higher-order mechanisms in accurately describing the few-body dynamics. One higher-order process that is particularly important in ionization is known as post-collision interaction (PCI) where the projectile and the ejected electron interact with each other again after the primary interaction. It is well known that PCI maximizes when the ejected electron has the velocity equal to that of the projectile however, kinematically complete data were completely lacking in this region. We have performed kinematically complete experiments on ionization of H2 and He by 75 keV proton impact. The momentum analyzed scattered projectiles and recoil ions were measured in coincidence and the ejected electrons’ momenta were deduced from the conservation laws. Fully differential cross sections (FDCS) were measured for various fixed electron energies for each of the targets near the projectile-electron velocity matching region. Pronounced post-collisional effects between the projectile and the ejected electron were observed in the projectile scattering angle dependence, the electron emission angle dependence, and the electron energy dependence of the FDCS. The results were compared with two conceptually very similar calculations. Surprising differences were observed not only between experimental data and theory but also between similar theoretical models. This shows that the FDCS are very sensitive to the details of the underlying few-body dynamics in this region.

Abstract Number ANPA2020_0010
Author/s Anish Maskey
Title Effect of DC biased voltage and temperature on bounded ion-ion plasma
Affiliation/s Tribhuvan University
Abstract A one dimensional particle-in-cell (PIC) simulation method has been employed to study the effect of DC voltage and ion temperature on the properties of ion-ion plasma bounded by two symmetrical but oppositely biased electrodes. It is assumed that ion-ion plasma is collisionless and both the positive and negative ion species have same mass, temperature, and degree of ionization. Simulation results show that the formation of sheath and presheath regions and fluctuation of plasma parameters in that region are affected by the biasing voltage and ion temperature. It is found that the magnitude of electrostatic electric field at the vicinity of biasing electrodes is affected by the biasing voltage and ion temperature as well. This strong electric field close to the electrodes further prevents the flow of charged particles towards the electrodes. The presence of non-zero electric field at the quasineutral region suggests a presheath region similar to the electron-ion plasma. In the quasineutral region, the density of ions increases with the increase of biasing voltage and decreases with the increase in ion temperature of isothermal ions, respectively. Furthermore, the phase space diagrams for the ions are obtained which indicates the different regions of the plasma. The positive ions acquire negative velocity towards the negatively biased electrode and the negative ions acquire positive velocity towards the positively biased electrode.

Abstract Number ANPA2020_0015
Author/s Atit Deuja,Anish Maskey, Suresh Basnet, Raju Khanal
Title Effect of DC biased voltage and temperature on bounded ion-ion plasma
Affiliation/s Tribhuvan University
Abstract The plasma interaction on plasma facing materials has wide range of applications such as in fusion devices, plasma diodes, surface modification of materials, sputtering and many more. A one-dimensional (1d) electrostatic Particle-in-Cell (PIC) model has been used for bounded plasma system (single-emitter plasma diode) to investigate the interaction of plasma on the collector surface. It is assumed that the plasma is collisionless and electrons and ions have cut-off Maxwellian velocity distribution at the injecting side. It is found that the ion and electron concentrations decrease toward the collector surface. The ions are accelerated towards the negative biased surface whereas the electrons are repelled from it. However, those electrons having high thermal mobility can reach the collector surface. The sharp monotonic decrease of electrostatic potential near emitter and collector regions implies the formation of plasma sheath with collector sheath thickness larger than that of emitter. It is found that the electron and ion densities are dominant near the emitter and collector surfaces, respectively. In addition, the particle reflection coefficient decreases for both molybdenum (Mo) and tungsten (W) surfaces with the increase in impact energy of ion, however, the reflection coefficient for W-surface is higher than that of Mo-surface about 34.43% in magnitude. The obtained results are compared with previous work and found to be in reasonable agreement.

Abstract Number ANPA2020_0021
Author/s Binayak bhulun lama ,Lekha nath Mishra,Roshan Chalise
Affiliation/s Patan Multiple Campus, Tribhuvan University
Abstract The present work deals about the Non-Maxwellian electron plasma where one of the velocities of a species does not follow a Maxwell-Boltzmann distribution. It is characterized on the influence of temperature with the help of simulation. It is based on kinetic approach. It is very useful for food processing to kill the bacteria in fruits, vegetables and other foods with fragile surfaces.