Cheap and efficient photovoltaic devices made from abundant elements in a low energy manner are a desirable goal for mankind. At the heart of a thin film photovoltaic device is an inorganic compound semiconductor, called an absorber layer, whose job is to absorb incoming light radiation and convert it into excited electrical carriers that may be separated at a p-n junction. The best absorber layer to date is Cu(In,Ga)Se2 which gives devices with power conversion efficiencies of over 20 %, which is directly competitive with silicon based technologies. However, for large scale terrestrial deployment alternative materials must be found as indium and gallium are not very earth abundant. Alternatives to this material are now currently being researched, with most focus given to the kesterite compound, Cu2ZnSn(S,Se)4. Power conversion efficiencies of over 11 % have been achieved so far in a relatively short amount of time. One major challenge with this material relates to synthesizing it single phase in thin films. It consists of four elements and has a fairly narrow region of single phase existence, thus the formation of secondary phases is likely. Most of the secondary phases are considered harmful to the performance of the device. One alternative to the kesterite is the p-type ternary compound Cu2SnS3. It contains one element less than the kesterite, and also only consists of abundant non-toxic elements. The material itself is hardly studied at all, but shows great promise as an absorber layer. Preliminary work in our laboratory has shown that it has suitable opto-electronic properties to be used as an absorber layer, culminating in a working device with an efficiency of 0.5 %. The aim of this project is to investigate and understand the synthesis, and the material and opto-electronic properties of thin films of Cu2SnS3. The synthesis will be made in a two step manner developing two different types of precursors and post-annealing them in a controlled vapor pressure furnace. Material properties will be investigated by SEM, EDX, Raman, and XRD. Opto-electronic measurements will be studied by Photoluminescence, and Photoelectrochemistry. Finally absorber layers will be built into full device structures and the opto-electronic properties of the devices will be investigated.