Quasi two-dimensional layered perovskite material, related devices and methods for manufacturing the same 

Perovskites are of interest as the active layer within PhotoVoltaic (PV) cells.  Here, it is indicated that 2D metal-halide perovskites provide compelling optoelectronic behaviour compared to their 3D counterparts.  However, dangling bonds (e.g. Pb) at the edges of the 2D sheet can adsorb oxygen ions.  Subsequent electron transfer to the oxygen ion provides a so-called O singlet, which is quite reactive.  Some compounds are known to passivate the dangling bonds, but these are not robust with respect to further processing (e.g. annealing).

Here, a passivating agent is provided at the edges of a quasi 2D sheet, where the agent bonds to the edges i.e dangling bonds.  The agent is said to act like a Lewis base and in one example it is a phosphine oxide compound.  In terms of structure, first and second electrodes are located on either side of the perovskite layer.  The passivating agent is located at the edge of the perovskite.  The perovskite makes a conductive contact with the electrode.  In some examples, hole and electron transport layers (e.g. coating) are located between the  perovskite, at the appropriate electrode, and the electrodes.  Further layers, including a so-called meso-porous metal oxide may be integrated in the structure.