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Full-Text Articles in Engineering

Tailoring The Grain Boundaries Of Wide-Bandgap Perovskite Solar Cells By Molecular Engineering, Khalid Emshadi Jan 2020

Tailoring The Grain Boundaries Of Wide-Bandgap Perovskite Solar Cells By Molecular Engineering, Khalid Emshadi

Electronic Theses and Dissertations

Due to the attraction of fabricating highly efficient tandem solar cells, wide-bandgap perovskite solar cells have attracted substantial interest in recent years. However, polycrystalline perovskite thin-films show the existence of trap states at grain boundaries, which diminish the optoelectronic properties of the perovskite and thus remains a challenge. This research demonstrates a one-step solution-processing of the [MA0.9Cs0.1Pb(I0.6Br0.4)3] wide-bandgap perovskite using Phenylhydrazine Iodide with amino groups to successfully passivate the trap density within grain boundaries and increase the perovskite grain size. The reinforced morphology and grain boundaries treatment considerably enhanced the photovoltaic performance …


Computational Intelligence Approaches For Energy Optimization In Microgrids, Tamal Roy Jan 2020

Computational Intelligence Approaches For Energy Optimization In Microgrids, Tamal Roy

Electronic Theses and Dissertations

The future electrical system termed as smart grid represents a significant paradigm shift for power industry. Nowadays, microgrids are becoming smarter with the integration of renewable energy resources (RESs) , diesel generators , energy storage systems (ESS), and plug-in electric vehicles (PEV or EV) . However, these integration bring with new challenges for intelligent management systems. The classical power generation approaches can no longer be applied to a microgrid with unpredictable renewable energy resources. To relive these problem, a proper power system optimization and a suitable coordination strategy are needed to balance the supply and demand. This thesis presents three …


Enhanced Charge Carrier Dynamics And Defects Passivation In Hybrid Perovskite Solar Cell Using A Novel Organic Halide Salt, Md Ashuqur Rahman Laskar Jan 2020

Enhanced Charge Carrier Dynamics And Defects Passivation In Hybrid Perovskite Solar Cell Using A Novel Organic Halide Salt, Md Ashuqur Rahman Laskar

Electronic Theses and Dissertations

In the last few years, active research works on hybrid perovskite solar cells (HPSCs) have been going on throughout the world as a part of clean energy revolution. HPSCs have already proved their potentiality as future solar technology through their promising photovoltaic performances and ability for low temperature based solution processing. Nevertheless, still there are remaining challenges of better charge carrier dynamics and defects minimization in HPSCs. Overcoming these challenges are very important to achieve high power conversion efficiency (PCE) practically. Aiming this, a novel organic halide salt called Phenylhydrazinium Iodide (PHAI) is introduced as additive with CH3NH …


Surface And Structure Engineering For Next Generation Lithium Metal Batteries, Ke Chen Jan 2020

Surface And Structure Engineering For Next Generation Lithium Metal Batteries, Ke Chen

Electronic Theses and Dissertations

Lithium (Li) metal has been considered as one of the most promising anode materials to replace conventional graphite for Li-ion battery due to its high theoretical capacity (3860 mAh g-1) and low electrochemical potential (-3.04 V vs standard hydrogen electrode). However, it still faces some problems such as unstable solid electrolyte interphase (SEI), uncontrolled Li dendrites growth, and infinite volume change during battery charging/discharging. To develop a stable and low-cost Li metal anode for next-generation Li metal battery, in this dissertation, we have made efforts to understand and solve these problems in two aspects, by introducing an artificial SEI and …


Optimization-Based Fast-Frequency Support In Low Inertia Power Systems, Ujjwol Tamrakar Jan 2020

Optimization-Based Fast-Frequency Support In Low Inertia Power Systems, Ujjwol Tamrakar

Electronic Theses and Dissertations

The future electrical energy demand will largely be met by non-synchronous renewable energy sources (RESs) in the form of photovoltaics and wind energy. The lack of inertial response from these non-synchronous, inverter-based generation in microgrids makes the system vulnerable to large rate-of-change-of-frequency (ROCOF) and frequency excursions. This can trigger under frequency load shedding and cause cascaded outages which may ultimately lead to total blackouts. To limit the ROCOF and the frequency excursions, fast-frequency support can be provided through appropriate control of energy storage systems (ESSs). For proper deployment of such fast-frequency control strategies, accurate information regarding the inertial response of …


Lithium-Ion Battery And Beyond: Oxygen Vacancy Creation In Tungsten Trioxide And Surface Modification Of Lithium Metal, Rajesh Pathak Jan 2020

Lithium-Ion Battery And Beyond: Oxygen Vacancy Creation In Tungsten Trioxide And Surface Modification Of Lithium Metal, Rajesh Pathak

Electronic Theses and Dissertations

The graphite-based anode material has a low theoretical specific capacity of 371 mAh g-1. The transitional metal oxides (TMOs) are considered a better choice owing to their relatively higher specific capacity. Among TMOs, tungsten trioxide (WO3) is considered promising due to a higher specific capacity of 693 mAh g-1, low cost, mechanically stable, and eco-friendly. It has been a challenge to utilize the TMOs as anode materials as they suffer from poor electronic conductivity and large electrode volume expansion during discharge/charge cycles. In our first project, we demonstrate a unique self-recovery of capacity in reduced WO3 by the incorporation of …


Distributed Machine Learning Approach To Fast Frequency Response-Based Inertia Estimation In Low Inertia Grids, Abodh Poudyal Jan 2020

Distributed Machine Learning Approach To Fast Frequency Response-Based Inertia Estimation In Low Inertia Grids, Abodh Poudyal

Electronic Theses and Dissertations

Recent updates to the IEEE 1547-2018 standard allow active participation of distributed energy resources (DERs) in power grid services with the goal of increased grid reliability and resiliency. With the rapid growth of DERs towards a low inertia converter-dominated grid, the DERs can provide fast frequency response (FFR) services that can quickly counteract the change in system frequency through inertial support. However, in low voltage grids, frequency and voltage face dynamics coupling due to a high resistance to reactance ratio and cannot be controlled separately as in the bulk electric grid. Due to the coupling effect, the control of one …