Tin sulfide (SnS) bears a huge potential for sustainable, low-cost and large-scale solar energy conversion and is currently generating great interest in materials science. SnS is a non-toxic material consisting of abundant and cheap elements and possesses a high absorption coefficient and a band gap of 1.3 eV, which is beneficial for its application in solar cells. Today, the highest power conversion efficiencies of SnS-based solar cells are up to 4.4% and are obtained in a thin film solar cell architecture in which the SnS layers are prepared by atomic layer deposition.^[1] Regarding fast and cost-efficient processing, the use of coating and printing techniques instead of vacuum-based processes is preferable. Therefore, also the research on solution-based fabrication methods for SnS layers and the deposition of SnS in combination with organic semiconductors to form hybrid solar cells is particularly interesting. In this contribution, we present a facile solution-based route for the preparation of nanostructured SnS layers and demonstrate their suitability for efficient charge generation in hybrid photovoltaic devices. The nanostructured SnS films are fabricated via a precursor solution containing tin(II) chloride and thioacetamide as sulfur source, which is coated on a substrate to form a precursor layer. The precursor film is then converted into SnS by thermal annealing in inert atmosphere. The resulting layers consist of a porous nanoplate network and can be infiltrated with a conjugated polymer to obtain a nanostructured hybrid heterojunction.^[2] The formation of the SnS films was investigated by time resolved X-ray scattering measurements using synchrotron radiation, which revealed information about growth kinetics of the nanoplates. A transient absorption spectroscopy (TAS) study on as prepared hybrid SnS/P3HT films showed that long-lived charges are generated in the layers upon illumination, highlighting their potential for solar cell applications. Furthermore, hybrid solar cells were prepared in inverted device architecture and showed promising short circuit currents up to 12 mA/cm². EQE measurements of the solar cells disclosed that these high photocurrents are based on current generation in a broad spectral range, which is due to a significant contribution of the SnS phase to charge generation.

[1] Sinsermsuksakul, P.; Sun, L.; Lee, S. W.; Park, H. H.; Kim, S. B.; Yang, C.; Gordon, R. G. Adv. Energy Mater. 2014, 1400496. [2] Rath, T.; Gury, L; Sánchez-Molina, I.; Martínez, L.; Haque, S. A. Chem. Commun. 2015, 51, 10198-10201.