Low temperature plasma treatment of MAPI perovskite

Methylammonium-lead-iodide (MAPI) perovskite, as one of the most promising light-absorbing material in solar cells, have been spin-coated on glass substrates and treated with a low temperature plasma. Plasma treatment have already been used to other parts of perovskite solar cells (PSC), such as electron/hole transport layers or electrodes, in order to achieve more suitable connection of interfaces, lower the charge recombination rate and obtain higher power conversion efficiencies (PCE). [1] However little is known about the effect of different plasmas used directly on the perovskite surface. As a plasma source, diffuse coplanar surface barrier discharge (DCSBD) has been used, placed directly into a glovebox with nitrogen atmosphere together with a photoluminescence (PL) measurement setup to exclude contact of samples with ambient air during and directly after treatments. PL measurements have revealed intriguing behavior dependent on a length of a plasma treatment. Chemical composition of a surface after treatment has been determined by an X-ray photoelectron spectroscopy.