Abstract
Tin halide perovskites (Sn HaPs) are the top lead-free choice for perovskite optoelectronics, but the oxidation of perovskite Sn2+ to Sn4+ remains a key challenge. However, the role of inconspicuous chemical processes remains underexplored. Specifically, the halide component in Sn HaPs (typically iodide) has been shown to play a key role in dictating device performance and stability due to its high reactivity. Here we describe the impact of native halide chemistry on Sn HaPs. Specifically, molecular halogen formation in Sn HaPs and its role on degradation is reviewed, emphasising the benefits of iodide substitution on improving stability. Next, the ecological impact of halide products of Sn HaP degradation and its mitigation are considered. The development of visible Sn HaP emitters via halide tuning is also summarised. Lastly, halide defect management and interfacial engineering for Sn HaP devices are discussed. These insights will inspire efficient and robust Sn HaP optoelectronics.
S.A.H acknowledges financial support from the Engineering and Physical Sciences Research Council (EPSRC grant number EP/R020574/1). S.A.H &L.L. thank support by the EPSRC Centre for Doctoral Training in Plastic Electronics (grant number EP/L016702/1).T.J.M thanks the Royal Commission for the Exhibition of 1851 for their financial support through a Research Fellowship.