Dye-Sensitized Solar Cells (DSSC) are third generation solar cells used as an alternative to traditional silicon solar cells. DSSCs are characterized by their durability, easy handling and ability to perform better under diverse lighting conditions which makes them an ideal choice for indoor applications. However, DSSCs suffer from several limitations including low efficiencies, susceptibility to electrolyte leakage under extreme weather conditions, and the need for expensive materials and fabrication techniques which limits their large-scale industrial applications. Addressing these limitations through efficient design and manufacturing techniques are critical in ensuring that the DSSCs transform from the current small-scale laboratory levels to sizeable industrial production. This research attempts to address some of these significant limitations by introducing the concepts of nature-inspired fractal-based design followed by the additive manufacturing process to fabricate cost-effective, flexible counter electrodes for DSSCs. The new conceptual fractal-based design counter electrodes overcome the limitations of conventional planar designs by significantly increasing the number of active reaction sites which enhances the catalytic activity thereby improving the performance. The fabrication of these innovative fractal designs is realized through cost-effective manufacturing techniques including additive manufacturing and selective electrochemical co-deposition processes. The results of the study suggest that the fractal-based counter electrodes perform better than conventional designs. Additionally, the fractal designs and additive manufacturing technology help in addressing the problems of electrolyte leakage, cost of fabrication, and scalability of DSSCs.

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Nanomachining of brittle materials is required in a wide range of applications. This paper reports on the feasibility studies of" vibration-assisted nano-impact machining by loose abrasives (VANILA), a novel nanomachining process for target-specific nanomachining of hard and brittle materials. A mathematical model based on Hertzian fracture mechanics theory has been developed to evaluate the feasibility of material removal in the VANILA process, where hard abrasive grains impact the brittle workpiece suiface. Experimental investigations are conducted using a commercially available atomic force microscope (AFM), to validate the feasibility of the proposed process. Several nanocavities with circular shape, having depths ranging from 6 to 64 nm and diameters ranging from 78 to 276 nm, are successfully machined. Patterns of nanocavities are machined to confirm the repeatability and controllability of the process. Observation of tool tips using a scanning electron microscope (SEM) reveals that the tool wear in the VANILA process is lesser than that observed in indentation process.

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The momentum of the additive manufacturing research is on a spurt. Additive manufacturing, also known as 3D printing process has been attracting the attention of the manufacturing community worldwide over the past decade. The 3D printing technology promises significant advances and applications in the area of automobiles, electronics, and medical devices and so on. However, this technology currently suffers from several limitations including large time consumption, need for support structures and limited range of material selection. This prevents its application in mass production. Holographic 3D printing, also referred to as (volumetric additive manufacturing) process is a very recent technique which uses multiple light beams intensified to form a build volume. A photosensitive liquid resin is solidified using the principle of constructive interference. The single light beam is not enough to produce the required intensity to cure the resin. While the combined interference could generate the required energy. The resulting part is printed in a fraction of seconds at once in contrast with the traditional 3D printing technology. This research studies the feasibility of a novel holographic volumetric additive manufacturing with an ultraviolet source of 365 nm as the primary source of energy. This propels the polymeric photochemical reaction between the monomer molecules. Also, experiments are conducted, incorporating various viscosity levels of the photopolymer material to suppress the oxygen dissolution. At the same time to observe the rate of curing of the photopolymer material. Finally, the mechanical properties of the build volume are analyzed.

Smart ceramic materials are next generation materials with the inherent intelligence to adapt to change in the external environment. These materials are destined to play an essential role in several critical engineering applications. Machining these materials using traditional machining processes is a challenge. The laser beam micromachining (LBMM) process has the potential to machine such smart materials. However, laser machining when performed in air induces high thermal stress on the surface, often leading to crack formation, recast and re-deposition of ablated material, and large heat-affected zones (HAZ). Performing laser beam machining in the presence of a liquid medium could potentially resolve these issues. This research investigates the possibility of using a Liquid Assisted-Laser Beam Micromachining (LA-LBMM) process for micromachining smart ceramic materials. Experimental studies are performed to compare the machining quality of laser beam machining process in air and in a liquid medium. The study reveals that the presence of liquid medium helps in controlling the heat-affected zone and the taper angle of the cavity drilled, thereby enhancing the machining quality. Analytical modeling is developed for the prediction of HAZ and cavity diameter both in air and underwater conditions, and the model is capable of predicting the experimental results to within 10% error.

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