Electrical and Computer Engineering Commons^™

Foreword For The Inaugural Issue, Dongming Guo, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

The International Journal of Extreme Manufacturing is a leading, worldwide scientific journal focused on the fields of extreme manufacturing. Published within it are the latest scientific and engineering achievements in related fields, as well as pioneering scientific, technological, and engineering innovations and developments.

Zebrafish Macroh2a Variants Have Distinct Embryo Localization And Function, E. Gonzalez-Munoz, Y. Arboleda-Estudillo, S. K. Chanumolu, H. H. Otu, J. B. Cibelli

Department of Electrical and Computer Engineering: Faculty Publications

Mouse and cell-based studies have shown that macroH2A histone variants predominantly associate with heterochromatin. Functional studies found that macroH2As are involved in gene repression, inhibiting the acquisition of pluripotency and preserving cell differentiation. However, only a few studies have analysed the role of macroH2A during early embryo development. We report the development of transgenic zebrafish lines expressing macroH2A isoforms (mH2A1 and mH2A2) fusion proteins (with GFP) under identified endogenous promoters. We found that mH2A1 and mH2A2 have different spatial and temporal expression patterns during embryonic development. mH2A1 is expressed mostly in the extraembryonic Yolk Syncytial Layer (YSL) starting before shield …

Rechargeable Multi - Cell Battery, Wei Qiao, Taesic Kim, Liyan Qu

Department of Electrical and Computer Engineering: Faculty Publications

A method for power management of a multi-cell battery includes identifying a desired power value and voltage value, determining a battery voltage value and a battery current value for a battery, determining a number of battery banks from a plurality of battery banks to use for the battery, where each battery bank includes one or more battery cells (or battery modules), checking availability of each of the one or more battery cells (or battery modules), selecting one or more battery banks from the plurality of battery banks, where the selection of a battery bank is based on the availability of …

Longitudinal Phonon Plasmon Mode Coupling In Β-Ga2O3, Mathias Schubert, Alyssa Mock, Rafal Korlacki, Sean Knight, Zbigniew Galazka, Günther Wagner, Virginia Wheeler, Marko Tadjer, Ken Goto, Vanya Darakchieva

Department of Electrical and Computer Engineering: Faculty Publications

In this letter, we investigate a set of n-type single crystals of monoclinic symmetry β-Ga₂O₃ with different free electron concentration values by generalized far infrared and infrared spectroscopic ellipsometry. In excellent agreement with our previous model prediction, we find here by experiment that longitudinal-phonon-plasmon coupled modes are polarized either within the monoclinic plane or perpendicular to the monoclinic plane. As predicted, all modes change the amplitude and frequency with the free electron concentration. The most important observation is that all longitudinal-phonon-plasmon coupled modes polarized within the monoclinic plane continuously change their direction as a function of …

Phase Resolved Partial Discharge Evaluation At Dc Voltage, Tobias Dezenzo

Doctoral

Partial discharge diagnostics are common for the condition assessment of high voltage alternating current (ac) and direct current (dc) equipment. For ac applications the phase resolved partial discharge evaluation method has prevailed [1]. Even though, numerous methods for dc partial discharge diagnostics have been proposed no agreed standard exists. This is primarily because of the fact that these methods are not as easily applicable as the well-known, intuitive, pattern based phase resolved method. Due to the often assumed unavailability of a useable phase angle information [2]–[4] this method has never been transferred to dc partial discharge diagnostics. However, as a …

การตั้งเป้าหมายพลังงานและการเพิ่มประสิทธิภาพการใช้พลังงานของเครื่องจักรการผลิตในโรงงานเคมีภัณฑ์, อังคนา สังข์ทองจีน

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยฉบับนี้ศึกษาถึงการใช้พลังงานของโรงงานเคมีภัณฑ์ตัวอย่าง โดยเก็บข้อมูลเป็นระยะเวลา11เดือนของการใช้พลังงานจากระบบการติดตามการใช้พลังงาน (Energy Monitoring System) และ ข้อมูลของปริมาณผลผลิตต่อวันมาวิเคราะห์เพื่อเป้าหมายการใช้พลังงานและเพิ่มประสิทธิภาพการจัดการพลังงานของโรงงานตัวอย่าง โดยแยกย่อยศึกษาแต่ละระบบในพื้นที่นั้นซึ่งประกอบด้วย ระบบไฟฟ้าสำหรับเครื่องจักรการผลิต ระบบอากาศอัด ระบบไฟส่องสว่าง ระบบระบายอากาศ และ ระบบทำความเย็น เพื่อกำหนดพลังงานฐาน (Energy Baseline) และ กำหนดเป้าหมายพลังงาน (Energy Target) ของพื้นที่การผลิตรายอาทิตย์และรายเดือนด้วยสมการเชิงเส้นแบบง่าย ในการวิเคราะห์ข้อมูลสำหรับการใช้พลังงานของระบบที่ขึ้นอยู่กับปริมาณการผลิต และใช้ค่าที่ดีที่สุดกำหนดเป้าหมายการใช้พลังงานของระบบที่ปริมาณการใช้พลังงานไม่ขึ้นกับปริมาณการผลิต รวมทั้งนำข้อมูลการใช้พลังงานที่ความละเอียดทุก 30 วินาทีเปรียบเทียบกับโปรไฟล์อุณหภูมิของเครื่องจักร CMMP ซึ่งเป็นเครื่องจักรสำหรับสร้างรูปทรงของชิ้นงาน จากการศึกษาพบว่าถ้าไม่มีแผนการผลิตนานกว่า 3 ชั่วโมงควรเปลี่ยนจากสแตนด์บายโหมด (Standby Mode) เป็นการปิดเครื่องเมื่อไม่ใช้งานจะลดปริมาณไฟฟ้าที่ใช้ได้เฉลี่ย 390 kWh/day และเพื่อการสื่อสารที่ชัดเจนกับผู้เกี่ยวข้อง งานวิจัยฉบับนี้ได้มีการสร้างกระดานสรุปข้อมูลการใช้พลังงาน (Energy Dashboard) ด้วย Microsoft Power Bi เพื่อติดตามการใช้พลังงานรายวันของแต่ละพื้นที่การผลิต และมีกิจกรรม Green day เพื่อเพิ่มความตระหนักต่อการใช้พลังงานของพนักงานในโรงงาน

การพยากรณ์ค่าอุณหภูมิของน้ำมันด้านบนในหม้อแปลงไฟฟ้ากำลังสำหรับการประเมินสมรรถนะโดยใช้แบบจำลองการเรียนรู้ของเครื่อง, สุวพันธุ์ อริเดช

Chulalongkorn University Theses and Dissertations (Chula ETD)

อายุการใช้งานที่สูญเสียไปจากการใช้งานหม้อแปลงมีสาเหตุหลักมาจากค่าอุณหภูมิที่เกิดขึ้นภายในหม้อแปลง ได้แก่ค่าอุณหภูมิขดลวดและอุณหภูมิน้ำมัน หม้อแปลงที่ทำงานในสภาวะการจ่ายโหลดและอุณหภูมิแวดล้อมค่าหนึ่งจะเกิดความร้อนภายในที่แตกต่างกันทั้งนี้ขึ้นอยู่กับสภาพในปัจจุบันและการเสื่อมสภาพในอดีตของหม้อแปลง วิทยานิพนธ์นี้ศึกษาแบบจำลองการเรียนรู้ของเครื่องที่สามารถเรียนรู้พฤติกรรมการเกิดความร้อนภายในหม้อแปลงโดยใช้ข้อมูลในอดีตเพื่อพยากรณ์ค่าอุณหภูมิน้ำมันด้านบนและอุณหภูมิขดลวดของหม้อแปลงที่จะเกิดขึ้นก่อนการใช้งานจริง ข้อมูลดังกล่าวสามารถนำมาหาอายุการใช้งานที่คาดว่าจะสูญเสียไปของหม้อแปลงแต่ละตัวเพื่อใช้ในการวางแผนการส่งจ่ายกำลังไฟฟ้าและการเลือกบำรุงรักษาอุปกรณ์ นอกจากนี้การใช้ขอบเขตการพยากรณ์ช่วยตรวจสอบข้อมูลพฤติกรรมทางความร้อนของหม้อแปลงเพื่อใช้ตรวจหาสัญญานที่อาจบ่งชี้ความผิดปกติหรือการเสื่อมสภาพของหม้อแปลงได้ โดยจากผลการทดสอบแสดงให้เห็นว่าข้อมูลจากแบบจำลองการเรียนรู้ของเครื่องสามารถพยากรณ์อายุการใช้งานที่สูญเสียของหม้อแปลงได้ใกล้เคียงกับการใช้ข้อมูลที่ตรวจวัดได้จริง นอกจากนี้วิทยานิพนธ์ฉบับนี้เสนอการสร้างขอบเขตการพยากรณ์เป็นอีกหนึ่งวิธีที่ช่วยในการติดตามความเปลี่ยนแปลงพฤติกรรมทางความร้อนของหม้อแปลงซึ่งมีประโยชน์ในการบริหารจัดการหม้อแปลง

Analysis Of Human Emf Exposure In 5g Cellular Systems, Imtiaz Nasim

College of Graduate Studies: Theses & Dissertations

Increasing concerns of communications at a frequency spectrum higher than 6 GHz have gained international alarm that suggests more research is needed before it is deployed successfully. In this context, in the first part of this thesis, we investigated the human electromagnetic field (EMF) exposure in indoor and outdoor environments from fifth-generation (5G) downlink communications and compared its impacts with the present cellular technologies considering the features that the 5G will likely adopt. The second part focuses on mitigation of human exposure for both indoor and outdoor environments with two different methods adopted. Our simulation results suggest that while the …

Compact Broadband Triple-Ring Five-Port Reflectometer For Microwave Brain Imaging Applications, Toufiq Md Hossain, Mohd Faizal Jamlos, Mohd Aminudin Jamlos, Ping Jack Shoh, Siti Zuraidah Ibrahim, Muammar Mohamad Isa, Dominque M.M.-P. Schreurs, Adam Narbudowicz, Mohd Fairusham Ghazali

Articles

The broadband five-port refectometer (FPR) is proposed using a triple-ring based technique. The design introduces a tapering in the inter-ring transmission lines (TLs), which provides additional degrees of freedom for optimization and contributes to increased bandwidth. The miniaturization strategy allows incorporating the third ring without signifcant size increase. In addition, a method for expressing the effective physical dimension of a planar symmetric FPR is also presented in an easily comprehensible way, which can be implemented for other symmetric planar junctions with more than four ports. The proposed design comprises three concentric rings with phase-shifting arrangements between the inter-ring TLs and …

N-I-P Nanocrystalline Hydrogenated Silicon Solar Cells With Rf-Magnetron Sputtered Absorbers, Dipendra Adhikari, Maxwell M. Junda, Corey R. Grice, Sylvain X. Marsillac, Robert W. Collins, Nikolas J. Podraza

Electrical & Computer Engineering Faculty Publications

Nanocrystalline hydrogenated silicon (nc-Si:H) substrate configuration n-i-p solar cells have been fabricated on soda lime glass substrates with active absorber layers prepared by plasma enhanced chemical vapor deposition (PECVD) and radio frequency magnetron sputtering. The cells with nanocrystalline PECVD absorbers and an untextured back reflector serve as a baseline for comparison and have power conversion efficiency near 6%. By comparison, cells with sputtered absorbers achieved efficiencies of about 1%. Simulations of external quantum efficiency (EQE) are compared to experimental EQE to determine a carrier collection probability gradient with depth for the device with the sputtered i-layer absorber. This incomplete …

Fabrication Of Ultra-Fine Cathodes For Cold-Field Emission, Srujana Valluri

Graduate Research Theses & Dissertations

This thesis discusses the different fabrication steps involved in producing ultra-fine cathodes that are suitable for cold field emission. A four-step nanofabrication process has been developed to obtain the cathodes with tip diameters ranging from 10nm to 20 nm. First, a mask is patterned on a 2-inch silicon wafer using monodisperse 1.18µm silica spheres. These particles are self-assembled using vortex-flow enabled assembly technique to form close-packed monolayers. Then the silicon is etched using a reactive ion etching technique. An inductively coupled plasma etcher is used to perform anisotropic and isotropic etching. The etching recipes used are chosen such that they …

Energy Optimization And Coordination Frameworks For Smart Homes Considering Incentives From Discomfort And Market Analysis, Priti Paudyal

Electronic Theses and Dissertations

The electricity demand is increasing with the growing use of electricity-based appliances in today’s world. The residential sector’s electricity consumption share is also increasing. Demand response (DR) is a typical way to schedule consumers’ energy consumption and help utility to reduce the peak load demand. Residential demand management can contribute to reduce peak electric demand, decrease electricity costs, and maintain grid reliability. Though the demand management has benefits to the utility and the consumers, controlling the consumers electricity consumption provides inconvenience to the consumers. The challenge here is to properly address the customers’ inconvenience to encourage them to participate and …

A Kinetic Monte Carlo Study Of Mesoscopic Perovskite Solar Cell Performance Behavior, Behzad Bahrami

Electronic Theses and Dissertations

Perovskite solar cells have received considerable attention in recent years due to their low processing cost and high energy conversion efficiency. However, the mechanisms of perovskite solar cell performance are not fully understood. Models based on probabilistic and statistical approaches can be used to simulate, optimize, and predict perovskite solar cell photovoltaic performance, and they can also guide experimental processing and fabrication conditions to achieve higher photovoltaic efficiency. This work developed a 3D model based on the kinetic Monte Carlo (KMC) approach to simulate 3D morphology of perovskite-based solar cells and predict their photovoltaic performance. The model incorporated the physical …

Aluminum And Silicon Metal-Semiconductor-Metal (Msm) X-Ray Photodetector, Cinthya Dallana Barbosa Medina

Graduate Research Theses & Dissertations

The main goal of this research was to construct a metal-semiconductor-metal (MSM) device, that could detect x-rays. The following thesis covers the theory behind MSM devices, as well as the theory of detecting x-rays. More importantly, we showed that aluminum was transparent to x-rays, therefore allowing our MSM device to detect only x-rays.

Both p-type and n-type MSM wafers resulted in the predicted Schottky curve. By analyzing our various configurations, we hypothesis the ideal dimensions for this device configuration. We also showed that the effect caused by the interaction with regular light.

Apart from what was accomplished in this paper …

Scheduling For Cooperative Energy Harvesting Sensor Networks, Ahmed Ammar

Graduate Theses, Dissertations, and Problem Reports (ETD)

In cooperative communication networks, the source node transmits its data to the destination either directly or cooperatively with a cooperating node. When using energy harvesting technology, where nodes collect their energy from the environment, the energy availability at the nodes becomes unpredictable due to the stochastic nature of energy harvesting processes. As a result, when the source has a transmission, it cannot immediately transmit its data cooperatively with the cooperating node. It first needs to determine whether the cooperating node has sufficient energy to forward its transmission or not. Otherwise, its transmitted data may get lost. Therefore, when using energy …

Immunity-Based Framework For Autonomous Flight In Gps-Challenged Environment, Mohanad Al Nuaimi

Graduate Theses, Dissertations, and Problem Reports (ETD)

In this research, the artificial immune system (AIS) paradigm is used for the development of a conceptual framework for autonomous flight when vehicle position and velocity are not available from direct sources such as the global navigation satellite systems or external landmarks and systems. The AIS is expected to provide corrections of velocity and position estimations that are only based on the outputs of onboard inertial measurement units (IMU). The AIS comprises sets of artificial memory cells that simulate the function of memory T- and B-cells in the biological immune system of vertebrates. The innate immune system uses information about …

Low-Power Reconfigurable Sensing Circuitry For The Internet-Of-Things Paradigm, Alexander Dilello

Graduate Theses, Dissertations, and Problem Reports (ETD)

With ubiquitous wireless communication via Wi-Fi and nascent 5th Generation mobile communications, more devices -- both smart and traditionally "dumb" -- will be interconnected than ever before. This burgeoning trend is referred to as the Internet-of-Things. These new sensing opportunities place a larger burden on the underlying circuitry that must operate on finite battery power and/or within energy-constrained environments. New developments of low-power reconfigurable analog sensing platforms like field-programmable analog arrays (FPAAs) present an attractive sensing solution by processing data in the analog domain while staying flexible in design. This work addresses some of the contemporary challenges of low-power wireless …

Energy Efficiency Evaluation Of Blower Heater Non-Purge Compressed Air Dryers, Alexandra M. Botts

Graduate Theses, Dissertations, and Problem Reports (ETD)

There are several compressed air dryers available for industrial use including, refrigerant, desiccant, and membrane. This research focuses on twin tower regenerative closed loop desiccant dryers, specifically: blower heater non-purge (BHNP) with and without cooling water pumps, Compressed-air Heater Purge (CHP), Blower Heater Purge (BHP), and Pressure Swing Heaterless (PSH). These styles of dryers are used mainly in industries that require extremely dry air such as, food manufacturing, medical air, or sensitive technology manufacturers. The research was conducted by collecting and analyzing real time current draw data on air compressors and associated dryers at eight different facilities (13 compressor systems) …

Low Power Voltage Reference Cells For Sensing Applications, Kody Ray Tucker

Graduate Theses, Dissertations, and Problem Reports (ETD)

Two low-power voltage reference cells for a system on-chip design are presented in this report. Both cells utilize a combination of standard transistors to produce an output voltage near 1 volt. Choosing the appropriate design procedures can aid in minimizing the temperature coefficient (TC) of the output reference voltage coming out of the cell. One circuit, covered first, is currently being fabricated on a standard 0.5 µm chip complementary metal oxide semiconductor (CMOS) process, while the other is still in the designing stage. The first one has a TC of 86 ppm/◦C with a reference voltage of 1.10 V while …

Engineering Plasmonic Nanostructures For Light Management And Sensing, Sujan Phani Kumar Kasani

Graduate Theses, Dissertations, and Problem Reports (ETD)

The two major global problems are to provide health safety and to meet energy demands for ever growing population on a large scale. The study of light interaction with nanostructures has shown a promising solution in improving the fields of bio-sensor and solar energy devices which addresses above mentioned two major global problems. Nanostructures have tunable physicochemical properties such as light absorption, electrical and thermal properties unlike bulk materials, which gives an advantage in applications like bio-sensing and energy harvesting devices. The development of nanofabrication techniques along with the discovery of Surface Enhanced Raman Scattering (SERS) and Plasmon Enhanced Fluorescence …

Resilient Stochastic Control Strategies In Cyber-Physical Microgrids, Mohammad Reza Khalghani

Graduate Theses, Dissertations, and Problem Reports (ETD)

Microgrids are the integration of a large number of distributed energy resources in a decentralized way such that the energy supply reliability and resiliency are enhanced against natural disasters, physical and cyber disruptions. This dissertation addresses three main challenges for microgrid operation and management:

1) According to fast growing number of Electric Vehicles (EV) deployment, their impacts on microgrids resulted from their uncertain behaviors are new concerns for the microgrid operators. These concerns can be EV charging and discharging schedule and locations of EV parking-lots in the system which are considered and solved using stochastic modeling and optimization algorithms based …

Engaging Undergraduate Students In The Philippines In Photonics Research With A Novel Publication-Driven Online Mentoring Approach, Minella C. Alarcon, Benjamin Dingel, Annelle Chua, Aria Buenaventura, Nathaniel Joseph C. Libatique

Electronics, Computer, and Communications Engineering Faculty Publications

This paper discusses a publication-driven, education-by-research model of engaging undergraduate students in Photonics/Optics/Physics research by requiring that all activities lead to journal publication within a year. It is based on a non-traditional university-industry collaboration arrangement that has the following unique features.

First, it utilizes offshore-based alumni (in the USA) who are active in science and technology research as mentors for the students (in the Philippines) in conjunction with the university professor advisers. We adopt inexpensive online collaboration technologies to support their virtual presence.

Second, our research topic “fuses” uniquely two separate courses of study, namely: (i) the traditional Special Relativity …

Optimal Compression Of Point Clouds, Benjamin Robert Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

Image-based localization is a crucial step in many 3D computer vision applications, e.g., self-driving cars, robotics, and augmented reality among others. Unfortunately, many image-based-localization applications require the storage of large scenes, and many camera pose estimators struggle to scale when the scene representation is large. To alleviate the aforementioned problems, many applications compress a scene representation by reducing the number of 3D points of a point cloud. The state-of-the-art compresses a scene representation by using a K-cover-based algorithm. While the state-of-the-art selects a subset of 3D points that maximizes the probability of accurately estimating the camera pose of a new …

State Estimation For An Agonistic‐Antagonistic Muscle System, Thang Tien Nguyen, Holly Warner, Hung La, Hanieh Mohammadi, Daniel J. Simon, Hanz Richter

Electrical and Computer Engineering Faculty Publications

Research on assistive technology, rehabilitation, and prosthetics requires the understanding of human machine interaction, in which human muscular properties play a pivotal role. This paper studies a nonlinear agonistic‐antagonistic muscle system based on the Hill muscle model. To investigate the characteristics of the muscle model, the problem of estimating the state variables and activation signals of the dual muscle system is considered. In this work, parameter uncertainty and unknown inputs are taken into account for the estimation problem. Three observers are presented: a high gain observer, a sliding mode observer, and an adaptive sliding mode observer. Theoretical analysis shows the …

High Order Volumetric Directional Pattern For Video-Based Face Recognition, Almabrok Essa, Vijayan Asari

Electrical and Computer Engineering Faculty Publications

Describing the dynamic textures has attracted growing attention in the field of computer vision and pattern recognition. In this paper, a novel approach for recognizing dynamic textures, namely, high order volumetric directional pattern (HOVDP), is proposed. It is an extension of the volumetric directional pattern (VDP) which extracts and fuses the temporal information (dynamic features) from three consecutive frames. HOVDP combines the movement and appearance features together considering the nth order volumetric directional variation patterns of all neighboring pixels from three consecutive frames. In experiments with two challenging video face databases, YouTube Celebrities and Honda/UCSD, HOVDP clearly outperformed a set …

Non-Hermitian And Space-Time Mode Management, Nicholas Nye

Electronic Theses and Dissertations

In the last few years, optics has witnessed the emergence of two fields namely metasurfaces and parity-time (PT) symmetry. Optical metasurfaces are engineered structures that provide unique responses to electromagnetic waves, absent in natural materials. On the other hand, PT symmetry has emerged from quantum mechanics, when a new class of non-Hermitian Hamiltonian quantum systems was shown to have real eigenvalues. In this work, we demonstrate how PT-symmetric diffractive structures are capable of eliminating diffraction orders in specific directions, while maintaining/enhancing the remaining orders. In the second part of this work, we emphasize on supersymmetry (SUSY) and its applications in …

Computational Imaging Systems For High-Speed, Adaptive Sensing Applications, Yangyang Sun

Electronic Theses and Dissertations

Driven by the advances in signal processing and ubiquitous availability of high-speed low-cost computing resources over the past decade, computational imaging has seen the growing interest. Improvements on spatial, temporal, and spectral resolutions have been made with novel designs of imaging systems and optimization methods. However, there are two limitations in computational imaging. 1), Computational imaging requires full knowledge and representation of the imaging system called the forward model to reconstruct the object of interest. This limits the applications in the systems with a parameterized unknown forward model such as range imaging systems. 2), the regularization in the optimization process …

Cryogenic Performance Projections For Ultra-Small Oxide-Free Vertical-Cavity Surface-Emitting Lasers, Mina Bayat

Electronic Theses and Dissertations

Small-sized vertical-cavity surface-emitting laser (VCSEL) may offer very low power consumption along with high reliability for cryogenic data transfer. Cryogenic data transfer has application in supercomputers and superconducting for efficient computing and also focal plane array cameras operating at 77 K, and at the lower temperature of 4 K for data extraction from superconducting circuits. A theoretical analysis is presented for 77 K and 4 K operation based on small cavity, oxide-free VCSEL sizes of 2 to 6 µm, that have been shown to operate efficiently at room temperature. Temperature dependent operation for optimally-designed VCSELs are studied by calculating the …

Design And Fabrication Of Scalable Multifunctional Multimaterial Fibers And Textiles, Felix Tan

Electronic Theses and Dissertations

Multimaterial fibers eschew the traditional mono-material structures typical of traditional optical fibers for novel internal architectures that combine disparate materials with distinct optical, mechanical, and electronic properties, thereby enabling novel optoelectronic functionalities delivered in the form factor of an extended fiber. This new class of fibers developed over the past two decades is attracting interest from researchers in such different fields as optics, textiles, and biomedicine. The juxtaposition of multiple materials integrated at micro- and nanoscales in complex geometries while ensuring intimate smooth interfaces extending continuously for kilometers facilitates unique applications such as non-invasive laser surgery, self-monitoring fibers, e-textiles, and …

Stable, Highly Luminescent Perovskite-Polymer Composites For Photonics Applications, Juan He

Electronic Theses and Dissertations

Metal halide perovskites (simplified as perovskites as below), particularly those in nanocrystal forms, have recently emerged as highly efficient, bandgap tunable photonics materials that can be easily solution processed at low cost for display, lighting or other energy conversion applications. However, the quick degradation of perovskite nanocrystals under external stresses or upon colloidal aggregations has been a major challenge for most applications where high reliability is normally required. In this thesis, we have explored a polymer swelling-deswelling microencapsulation (SDM) process that enables the dispersion, in-situ crystallization and subsequent surface passivation of perovskite nanocrystals in polymer matrices, and leads to ultrastable …