Recent advances in the use of plasmonic metamaterials to improve absorption of light in thin-film solar photovoltaic devices has created a demand for a scalable method of patterning large areas with metal nanostructures deposited in an ordered array. This article describes two methods of fabricating ordered 2D nanosphere colloidal films: spin coating and interface coating. The two methods are compared and parameter optimization discussed. The study reveals that: For smaller nanosphere sizes, ...
Thesize effect of nanoscale silicon in both amorphous and porous silicon was investigated with microRaman spectroscopy. Silicon nanostructers in amorphous silicon were deposited on quartz substrates by plasma enhanced chemical vapor deposition (PECVD) with deposition powers of 15, 30 and 50W. MicroRaman spectra of the nanostructured silicon show the T 2g Raman active mode shifting from the 521 cm 1 crystalline Si Raman line to 494, 499 and 504 cm 1 as deposition power increased. Large...
The agglomeration/dewetting process of thin silver films provides a scalable method of obtaining self-assembled nanoparticles (SANPs) for plasmonics based thin-film solar photovoltaic (PV) devices. Here, we show the effect of annealing ambiance on silver SANP average size, particle/cluster finite shape, substrate area coverage/particle distribution and how these physical parameters influence optical properties and surface-enhanced Raman scattering (SERS) responses of SANPs. Statistical analys...
Distributed digital manufacturing of free and open-source scientific hardware (FOSH) used for scientific experiments has been shown to in general reduce the costs of scientific hardware by 90–99%. In part due to these cost savings, the manufacturing of scientific equipment is beginning to move away from a central paradigm of purchasing proprietary equipment to one in which scientists themselves download open-source designs, fabricate components with digital manufacturing technology, and the...
Slot die coating is growing in popularity because it is a low operational cost and easily scaled processing technique for depositing thin and uniform films rapidly, while minimizing material waste. The complex inner geometry of conventional slot dies require expensive machining that limits accessibility and experimentation. In order to overcome these issues this study follows an open hardware approach, which uses an open source 3-D printer to both fabricate the slot die and then to functional...
Rapid manufacturing using 3-D printing is a potential solution to some of the most pressing issues for humanitarian logistics. In this paper, findings are reported from a study that involved development of a new type of 3-D printer. In particular, a novel 3-D printer that is designed specifically for reliable rapid manufacturing at the sites of humanitarian crises. First, required capabilities are developed with design elements of a humanitarian 3-D printer, which include, (1) fused filament ...
Micromorphology analysis of sputtered indium tin oxide fabricated with variable ambient combinations. Abstract This study experimentally investigates the fractal nature of the 3-D surface morphology of sputtered indium tin oxide (ITO) fabricated with five sets of ambient combinations. The samples were prepared on glass substrates by DC magnetron sputtering using argon, argon with oxygen, argon with oxygen and nitrogen, argon with oxygen and hydrogen and argon with oxygen, nitrogen and hydroge...
A systematic investigation is performed to determine the effects of the concentration of silver on metal assisted chemical etching (MaCE) on nanostructure formation mechanisms on silicon as well as their resultant optical properties. Silver nitrate concentrations of 0.008M, 0.004M, 0.003M and 0.002M with hydrogen fluoride were used for the preparation of p-type silicon nanostructures. Experimentally it is observed that when the catalysis molarity concentration is decreased in the etching proc...
Novel aluminum and indium doped zinc oxide bilayer transparent conducting oxide thin films have been developed by simple sol gel spin coating and annealed at 500 C for an hour under nitrogen ambient towards solar cell applications. The structural, electrical and optical properties of both the as deposited and annealed bilayer thin films are characterized. X-ray diffraction studies showed a hexagonal wurtzite-type structure of ZnO with (002) orientation, which was enhanced with annealing. In a...
A promising approach to reducing the >870,000 deaths/year globally from unsafe water is flow-through solar water pasteurization systems (SWPs). Unfortunately, demonstrated systems have high capital costs, which limits access for the poor. The most expensive component of such systems is the heat exchanger (HX). Thus, this study focuses on cost optimization of HX designs for flow-through SWPs using high-effectiveness polymer microchannel HXs. The theoretical foundation for the cost optimization...
In President John F. Kennedy’s original Consumer Bill of Rights speech to the United States Congress he called for the “right to be informed”. At the time, materials science was in its infancy and only crude information technology was available, so the need for consumers to know what materials their products were made up of was outweighed by the difficulty of providing the information. Fifty-five years later the basic material ingredients are largely unknown for the vast majority of con...
The open source introduction of fused filament fabrication (FFF) enables distributed manufacturing of consumer products. However, with a wide range of low-cost FFF 3-D printers and settings possible, there is a lack of information on the variability in printed mechanical properties. This paper utilizes a large pool of 47 user-assembled 3-D printers to quantify the mechanical property variations of ultimate tensile strength (UTS) and yield strength of FFF printed components using ASTM D638-14 ...
An approach using a differential evolution (DE) optimization algorithm is proposed to optimize design parameters for improving the optical absorption efficiency of plasmonic solar cells (PSC). This approach is based on formulating the parameters extraction as a search and optimization process in order to maximize the optical absorption in the PSC. Determining the physical parameters of three-dimensional (3-D) PSC is critical for designing and estimating their performance, however, due to the ...
A self-replicating rapid prototyper (RepRap) is a type of 3-D printer capable of printing many of its own components in addition to a wide assortment of products from high-value scientific or medical tools to household products and toys. There is some evidence that these printers could provide low-cost distributed manufacturing in underprivileged rural areas. For the most isolated communities without access to the electric grid, a low-cost alternative energy is needed. Solar energy can be har...
Recent theoretical developments in expanded microchannel polymer-based heat exchangers were promising, but the initial experiments underperformed simple theory. In order to understand this discrepancy, this paper introduces a nondestructive methodology for characterizing polymer heat exchangers. A computerized tomography (X-ray) scan was performed to diagnose the problem. The method was tested on the expanded microchannel polymer heat exchanger to determine the variations in geometry between ...