This PDF file contains the front matter associated with SPIE Proceedings Volume 11387, including the Title Page, Copyright information, and Table of Contents.

Multivalent organic batteries can be considered as sustainable, cheap and environmental friendly batteries with high energy density due to use of metal negative electrodes. Magnesium, calcium, aluminum metals can be successfully combined with redox active polymers after proper selection of electrolytes. Several challenges are facing multivalent batteries and further development is required. Redox mechanism in multivalent organic batteries is based on charge transfer on quinone groups, however depends on the electrolyte, besides multivalent cations (Mg2+, Ca2+, Al3+) also cation complexes or even partially solvated cations can be involved into charge transfer reaction. In this presentation, overview of recent achievements in our group on the field of multivalent batteries will be discussed with a focus on reaction mechanism and how different battery components can influence charge transfer reaction.

Development of new functional materials for novel energy conversion and storage technologies is often assisted by ab initio modeling. Such modeling is usually done at the molecular level. Modeling of aggregate state effects is onerous, as packing may not be known or large simulation cells may be required for amorphous materials. Yet aggregate state effects are essential to estimate charge transport rates, and they may also have substantial effects on redox potentials (voltages) and optical properties. We summarize our recent studies of aggregation effects on electronic properties of organic materials used in optoelectronic devices and in organic batteries.

Manufactured by Bell Labs in 1954, first modern silicon solar cells exhibited an efficiency of 6%. Research has continuously pushed this limit higher and reached 26.7% for a single-junction silicon solar cell in 2017. The family of different types of solar cells expanded in the lab as well as in commercial manufacturing and the installation of solar photovoltaic electricity generation systems still follows an exponential growth rate. In 1999, 45 years after the first modern silicon solar cells had been released, the cumulative installed photovoltaic electricity generation capacity reached 1 GW and by 2012 the total installed PV capacity reached 100 GW. Only five years later, in 2017, t100 GW became the annual market volume. As a consequence, the total world-wide installed photovoltaic electricity generation capacity exceeded 630 GW by the end of 2019.

Various processes lead to degradation of cathodes in lithium-ion batteries. Questions remain regarding mechanisms of many of these processes. Probe microscopy methods including scanning electrochemical microscopy (SECM) are capable of directly probing processes at the cathode/electrolyte interface. SECM uses a small electrode to perform rapid electrochemical analysis of transient species generated at an active cathode/electrolyte interface. This paper discusses the background of the SECM instrument and its application to lithium-ion battery research. We also describe the application of SECM methods to the study of cathode degradation processes observed in lithium-ion batteries. Specifically, we focus on characterizing the dissolution of manganese from LiMn₂O₄ (LMO) based on recent debate in the literature. We describe experiments to observe and characterize the electrochemical properties of manganese complexes emerging from degrading LMO electrode materials.

Energy harvesting from boy heat could represent an attractive technology for powering a variety of wearable sensors. Thermoelectric devices could be useful for personal energy harvesting. However, traditional thermoelectric energy harvesting devices are suffered from low efficiency, lack of flexibility or wearability, or the need for bulky heat sinks. Here, we developed a strategy to make flexible thermoelectric devices that are flexible, and more importantly, works at high efficiency without resorting to any heat sinks. The device was enabled by optimal thermal design and a novel approach to make flexible device from high-performance rigid inorganic thermoelectric materials.

Controlling thermal emission in the mid-infrared range is of great interests for thermal engineering with broad applications ranging from the solar-thermal absorber to thermal camouflage, from radiative cooling of spacecrafts and terrestrial objects to building envelopes, and heat shielding. In many these applications, it is often desirable to have selective absorptance in different parts of the spectrum. For example, for many solar utilization devices (such as solar-thermal, thermoelectric, and photovoltaics), absorption in the solar spectrum is desirable for harvesting solar energy to heat or directly into electricity. On the other hand, for cooling applications, it is preferred to have low solar absorption and high infrared emission. Achieving high spectral selectivity is a key strategy to enhance the figure of merit of the thermal absorbers or emitters. I will present my work aiming to achieve the spectral selective feature using nanostructures for these two opposite applications. Furthermore, I will introduce a novel approach to adopt nanostructures to manipulate thermal radiation. I could achieve a near-monochromatic far-field thermal emission, which is a big departure from the incandescent behavior as described by the Planck’s law. The key feature of the design is to utilize nanoscale emitters whose dimension is comparable to or smaller than the thermal wavelength, a regime when the Planckian energy distribution no longer holds. I will show my experimental and theoretical work to quantify the far-field thermal radiation from these rationally-designed nano-emitters. The result provides new insight into the realization of spatial and spectral distribution control for far-field thermal emission.

Efficient and low-cost thermal energy-harvesting systems are crucial to solve the global energy problem. A new energy conversion system for the generation of electric power directly from heat energy is described herein. The device is a sensitized thermal cell (STC) based on a dye-sensitized solar cell. In the established system, thermally-excited electrons in a semiconductor were utilized instead of photon-excited electrons in a dye. Consequently, the STC generated electricity by “placing” or “burying” the cell in the heat source. The present study summarized the recent results of the STC and the difference between photo excitation and thermally excitation.

Hybrid perovskites has recently emerged as a promising material for flatland optoelectronic and nanophotonic applications. In this report, we present our initial findings about probing the microscopic emission process using back focal plane spectroscopy. Our results highlight how the growth, induced defects and morphological heterogeneity modify the photoluminescence emission in hybrid perovskite nanostructured thin films. Furthermore, we explain our findings within the framework of back focal plane imaging principles.

A theoretical platform is developed to study design guidelines and strategies for implementation of nonlinear magnetic springs that are traditionally encountered in variety of vibration systems. The adopted magnetic spring consists of two fixed top and bottom ring magnets and a third solid magnet that is levitated between the two fixed magnets. Approximate analytical forms for the equivalent linear and nonlinear stiffness coefficients of the magnetic spring are derived and used to investigate the effect of different design parameters on behavior of the magnetic spring. Magnetic damping force model is presented. Experimental work is also carried out to validate model simulations. Results show excellent agreement between model and measured data. Findings from this work suggest that linear and nonlinear stiffness coefficients are often coupled. Outer diameter of the fixed ring magnets can be used to control the nonlinearity of a given magnetic springbased vibration system in order to achieve hardening nonlinear, softening nonlinear, or linear dynamic behavior. The work presented here serves as a roadmap for design and analysis of variety of magnetic spring-based vibration systems including vibration energy harvesting systems and vibration attenuation systems.

Applications for stand-alone systems with small form factor, long lifetime and high energy density have arisen. Nuclear batteries have the potential to achieve specific powers of 1-50mW/g and devices that utilize the beta emitter titanium tritide (TiT2) have the most potential. We present our progress in making textured TiT2 based devices and their performance as compared to planar devices. In planar devices a 200nm 4H-SiC P+N junction is used for charge collection. Dark current measured less than 6.1 pA/cm2. Samples measured with tritium foil produced an open circuit voltage of 2.09V, short circuit current of 75.47nA/cm2, fill factor of 0.86 and power efficiency of 18.6%. This device is near the practical limit efficiency. In order to increase the power output the effective area of the beta source is increased by patterning the topmost absorption layer into channels 10 micron in height. Textured devices achieved open circuit voltage of 1.91V and short circuit current of 11.3nA.

This paper illustrates the energy harvesting principle established in an optical micro-electro-mechanical system (MEMS) using a vertical multi-junction photovoltaic cell (PV cell: 3*3*0.1 mm). The micro-system is a bistable micro-actuator which includes two active shape memory alloy elements (SMA: 3*1*0.1 mm), heated by a laser beam. The SMA elements are used as a biasing spring to activate the micro-system. In this study, the focus is only on actuating the SMA while harvesting energy converted from laser lighting. First, the laser is homogenized using an N-BK7 light pipe homogenizing rod (75*2 mm). Then, the uniformity is verified experimentally using an optoelectronic system able to measure the power on every 800 μm of the surface; resulting an average output power of 100 mW with a variation of ±9%. Next, the current/voltage (IV) curve of the PV cell is extracted, for an irradiance of 1.05 W/cm², giving a maximum electric power of 32.5 mW. The set-up for the system is modelled using Creo software and executed by resin 3D printing. Finally, the actuation of each SMA element is done alternately (period = 6 sec) using a MEMS active mirror which steers the homogenized laser onto them. While cycling, the unused optical energy from the laser is detected by the PV cell resulting to harvest around 60 mJ per cycle. This energy is stored in a solid state thin film micro-battery. In the future work, the SMA elements will actuate the bistable micro-actuator and the quantity of energy harvested will be extracted.

There is currently significant interest in the development of thermoelectric generators (TEGs) that employ multi-phase fluids. While liquid TEGs show promise for harvesting waste heat or thermal energy without the limitations or material engineering associated with the Wiedemann-Franz law, the exact geometric designs of TEGs are still challenging to model, predict, and optimize, a priori. The difficulties in modeling TEG behavior may be related to the complex inter- and intra-molecular interactions that are not currently incorporated into thermodynamic model. Here we study the thermoelectric behavior with a range of molten salts or room temperature ionic liquids (RTILs) and correlate Seebeck coefficient with heat expansion. When an RTIL expands, it does work, and the voltage produced in the temperature gradient decreases. A thermodynamic two-chamber model that illustrates the measured trends associated with volumetric heat expansion is provided.

Thermoelectric devices are solid-state energy conversion devices that are used in thermal management and waste heat recovery applications. Current thermoelectric devices are limited in their geometries, and the manufacturing process is labor-intensive. The traditional manufacturing methods limit the widespread use of thermoelectric modules in potential application areas. To address this issue and expand the use of thermoelectric devices, we investigated laser powder bed fusion, an additive manufacturing technique that is also known as selective laser melting. We performed selective laser melting on bismuth telluride, a common thermoelectric material. This work explored Bi₂Se_0.3 Te_2.7, an n-type thermoelectric material. After laser processing, the meso-, micro-, and nanostructure of selectively laser melted samples were analyzed to identify the relationship between the laser parameters and processed materials. The meso- and micro-structure was investigated with optical and scanning electron microscopy to identify the grain structure and morphology. The nanostructure was analyzed using transmission electron microscopy to explore the location and density of dislocations and point defects. The results reveal the impact of selective laser melting process parameters on n-type bismuth telluride and guide future work in determining the process-structure relationship for laser additive manufacturing of thermoelectric devices.

This paper not only seeks to motivate the people of Puerto Rico to consider the purchase of electric vehicles but also, to pursue the implementation of solar recharging stations. An evaluation of the energetic consumption of internal combustion vehicles versus Electric Vehicles (EV) was made. As well, the damage to the planet Earth produced by conventional vehicles is contrasted. The calculations necessary for the construction of a solar charging station were demonstrated based on the energy consumption. Some future research has been highlighted.

Organic-inorganic hybrid perovskites have demonstrated tremendous potential for next-generation electronic and optoelectronic devices due to their remarkable carrier dynamics. Current studies are focusing on polycrystals since the controlled growth of high-quality single crystals is extremely challenging. Here I will discuss the first chemical epitaxial growth of single-crystal hybrid halide perovskites with controlled locations, morphologies, and orientations, using combined strategies of advanced microfabrication and low-temperature solution method. By controlling the lattice mismatch between the substrate and epilayer, strain magnitude and a wide range of functional properties can be readily tuned. This approach opens up broad opportunities for hybrid halide perovskite materials based high performance electronic and optoelectronic devices. A single crystalline hybrid halide perovskite-based solar cell with enhanced photoconversion efficiency is demonstrated.

Given the growing global demands on energy and fresh water, nuclear energy has become a promising source of power and freshwater production. Maximizing the nuclear power plant efficiency requires running the plant at maximum power capacity, however, the actual load might not require such huge power supply (1000 MWe +). Power plants operation with high to maximum efficiency has a profound effect on financial prices and environmental conditions for clear reasons which commands the attention towards various expensive and not efficient energy storage techniques (thermal, electrical and hydro). In this work, energy storage is substituted by a desalination plant that utilizes the excess energy to power the desalination unit. Therefore, this work explores the potential of water desalination as a proxy for energy storage systems in nuclear power plants. Various water desalination technologies are examined and compared in terms of economy, water quality and production capacity. Barakah nuclear power plant is used as a case study with APR1400 reactor design. On the desalination side, Reverse Osmosis (RO), Multi-Stage Flash (MSF), Multi-Effect Distillation (MED) and hybrid combinations are studied.

Geothermal energy is one of the most attractive clean, sustainable and renewable energy sources due to its independency on weather conditions as the case for solar and wind energy. A hybrid geothermal/solar system for power production is proposed. The proposed system could be considered as highly efficient and cost-effective system. A concentrated solar thermal power generation (CSP) of type parabolic trough collector (PTC) is selected to improve the efficiency of the cycle and increase the electricity output by increasing the temperature of the incoming geothermal fluid. By using this system, the net power generation will increase up to 10% in a month compared to normal systems, and 7.6% in a year.

The Earth is made up of 71% water, but the world still has water shortage, so what is the reason? The answer to that question is that 97% of the water available is salty water, and all of it has high salt content, which makes is impossible for drinking, consuming, and irrigation. The solution for this problem is desalination, it is the only way that we can get drinkable water, other than fresh resources. But desalination usually consumes a huge amount of electricity, so other sustainable sources to help in the process of desalination in a cleaner and more cost-effective way should be considered. In this work, two main technologies for water desalination using geothermal-powered systems are presented and discussed. These technologies are promising, especially in gulf region, where geothermal energy is available generously.

Surface texturing is very important in silicon solar cells fabrication. Generally, wet chemical etched is used to texture silicon wafer surfaces. However, wet chemical technique is not suitable for all types of silicon wafers due to different crystallographic orientation of grains. Therefore, in this paper, pulsed Nd:YAG laser is used to texturing silicon wafer surfaces. Laser texturing is chosen because it can be applied on any types of silicon wafers and it can work independently without relying on silicon wafer properties after all. Although laser can make a texture on silicon wafer surfaces, but there is some drawbacks of using laser texturing. Laser texturing produced unwanted particles and created surface damage layer with a lot of laser ablation residues. This unwanted particles and residues must be remove in order to avoid surface recombination on solar cells. A simple method was applied as a post treatment after laser texturing. To see the effects of silicon solar cells with and without laser texturing, before and after post-texturing cleaning steps, a reflectance measurement is conducted. The reflectance data from UV-Vis Spectrophotometer shown a huge reduction with lowest reflectance is achieved after laser texturing and post treatment which are from 40% to below 10% and 20% of reflectance, respectively. The lowest reflectance is achieved because the flat surfaces has been textured and it has a high roughness. Although the reflectance increase a little bit after post treatment, pulsed Nd:YAG laser texturing still a good technique to be used for texture silicon wafer because it can work independently on any types of silicon wafers..