Six techniques are used to measure the exciton diffusion length as a function of systematic chemical modifications.

We present a joint experimental and theoretical study of singlet exciton diffusion in spincoated P3HT films and its dependence on molecular weight. The results show that exciton diffusion is fast along the co-facial π-π aggregates of polymer chromophores and about 100 times slower in the lateral direction between aggregates. Exciton hopping between aggregates is found to show a subtle dependence on interchain coupling, aggregate size and Boltzmann statistics. Also a clear correlation is observed between the effective exciton diffusion coefficient, the degree of aggregation of chromophores and exciton delocalisation along the polymer chain, which suggests that exciton diffusion length can be enhanced by tailored synthesis and processing conditions. Submitted to 2

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Water is a quintessential element for the survival of mankind. Its variety of uses means that it is always in a constant state of demand. The supply of water most primarily comes from large reservoirs of water such as lakes, streams, and the ocean itself. As such, it is good practice to monitor its quality to ensure it is fit for human consumption. Current water quality monitoring is often carried out in traditional labs but is time consuming and prone to inaccuracies. Therefore, this paper aims to investigate the feasibility of implementing an Arduino-based sensor system for water quality monitoring. A simple prototype consisting of a microcontroller and multiple attached sensors was employed to conduct weekly onsite tests at multiple daily intervals. It was found that the system works reliably but is reliant on human assistance and prone to data inaccuracies. The system however, provides a solid foundation for future expansion works of the same category to elevate the system to being Internet of Things (IoT) friendly.

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