Ion mediated self-assembly of nanoparticles to develop nanoelectrodes

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Electrodes are critical components in electrochemical devices such as batteries, bio-sensors, electro-catalytical systems and supercapacitors, which permeate our life and are subject of intense research. Development of new electrodes is required to further expand their areas of application and also enhance their performance, to addresses the multitude of challenges that are arising in our society. A case is the changing life styles in developing countries and a rapidly ageing population world-wide (specifically in developed countries), which necessitates the use of electrochemical devices in bio-sensing to be rapidly advanced for developing continuous monitoring and point of care devices. This is vital as it will lead to better preventive care and early diagnosis, reducing the increasingly unsustainable burden on health care system. Diabetes is an example that illustrates this scenario, where electrochemical sensors are used for monitoring and the current challenge is to advance them to continuous monitoring capability to tackle the growing prevalence of this condition. The composition, geometry and the size of the electrode are the critical factors that determine the performance of electrochemical devices in these diverse ranges of applications. This is because the functioning of the electrode is based on a multitude of processes that involve mass transfer, electron transfer and flow of ions, to or near the electrode surface and hence are affected by these factors. In this program my objective is to use self-assembly of nanoparticles with targeted metal ions to make nanoelectrodes and study their electrochemical performance. The nanoparticles will form a branched 1-D branched structure that will then be transformed into a continuous nanoelectrode. The length scale of the nano-electrode will be in microns for facile integration into devices, while its other dimensions will be limited to 100 nm scale. These nanometer size scales compared to macro scale electrodes will ensure a rapid rate of mass transfer to the electrode surface, high signal to noise ratio, better sensitivity and faster stabilization times. The small size scales will also enable their use with limited power consumption and small analyte volumes that is critical for detection in body fluids such as tear, sweat and saliva. Hence they will be suitable for application in wearable electronics for continuous monitoring of biomolecules in body fluids. The program will focus on researching the use of different ions for the self-assembly of the nanoparticles, their subsequent transformation into a continuous nanoelectrode, the integration of the nanoelectrode as an electro-chemical device and testing to characterize its performance compared to a macro scale electrodes.