As the energy demand keeps rising and the need for clean, affordable energy increases, the switch to completely sustainable energy production comes closer and closer. Solar cells are expected to play a big role in this energy transition. However, the technology of the most used type of solar cell, crystalline silicon, is nearing its limit. This calls for other novel technologies that could surpass it. One of these promising technologies is the perovskite / c-Si tandem cell. This type of cell has shown promising results in recent years, but for it to be commercialized and challenge the current technologies that dominate the market, some steps need to be taken. This thesis focuses on hysteresis, a behaviour commonly shown in perovskite cells, resulting in an uncertainty when measuring the characteristics of these cells. The most common explanation for this behaviour has been due to ion migration under certain conditions. This report, however, looks at hysteresis from a different perspective. It investigates the effect of defects on the hysteresis behaviour, continuing on previous research on this mechanism. It is argued that the defects trap charge near the interfaces, affecting the charge extraction and with that the amount of recombination in the cell. This hypothesis is researched by modelling a state-of-the-art perovskite / c-Si tandem cell in TCAD Sentaurus. This research investigates multiple important parameters to these defects, such as defect density, distribution, energy level, and capture cross-section. With these variables, the hysteresis behaviour as a result of the defects is explored. These results are then used to compare the hysteresis behaviour of the tandem cell with a similar single-junction cell, after which the difference between the two is analysed. It is found the two types of cells have similar hysteresis behaviours, but not equal. With the main deviation finding its origin in the current-limiting that can be displayed by tandem cells.

This report details the software part of the development process of the eNose technology. The technology is posed by Momo Medical. Momo Medical is a start-up company located in Delft, it provides and develops non-intrusive monitoring systems in the nursing sector. The project is the next step in an already existing product: BedSense. BedSense enables nurses to check for among others decubritus, whether the patient is out of bed, and even if the patient has passed away. The finished project will be able to detect solid stool and hence, when integrated into the system of BedSense, will greatly assist the nurses.

The eNose technology is able to detect solid bowel movement using its gas sensing abilities. It consists of gas sensors that detect the relevant gasses that are related to feces. These sensor values are then fed into an algorithm that is able to interpret them and detect defecation. Besides it includes a communication system that handles the internal and external communication. Finally, the technology supports Over The Air (OTA) updates which allows to update the firmware of the devices remotely.

The final prototype functions accurately in certain restrooms and can be regarded as a proof of concept.However more work and data is needed in order to make the eNose work in various environments, with possible integration of machine learning analysis, as it has showed great potential.

The project is executed in two groups, hardware and software. This report contains only the software part of the process. It includes the development of the detection algorithm. And the developmentof a communication and OTA programming system.