This thesis details an investigation into the factors that could be restricting the performance of tin sulfide thus far. It is shown that there is confusion in the literature with respect to the assignment of different tin sulfide phases, and that the presence of these phases cannot easily be discerned with routine diffraction methods. In order to better understand the behaviour of tin sulfide in devices, it is important to isolate these materials as separate components and to consider the distinct properties of each. %Indeed, even a fundamental property such as the colour of SnS is still subject to conflicting reports. Herein, the targeted synthesis of SnS, SnS2 and Sn2S3 by chemical vapour transport is used to produce phase-pure single crystals, which are characterised in terms of structural, optical and electrical properties. These are compared directly with results from modern simulation methods as well as the work of others to explore fully the possible origins of performance losses. It is found that the work function of SnS is significantly lower than those of alternate successful photovoltaic materials, which means that novel device architectures are necessary in order to unlock the full potential of this promising photo-absorber. Concerns are also raised regarding the stability of the tin monosulfide phase with respect to degradation and defect formation over time, processes that undoubtedly affect device performance and lifetimes if sufficient safeguards are not put in place to suppress them. Further results of this 3 year research project also provide a broader platform for achieving sustainable light harvesting devices from the abundant and cheap elements, tin and sulfur.
|Date of Award||2 Dec 2014|
|Supervisor||Aron Walsh (Supervisor) & Chris Bowen (Supervisor)|