Creation and Annihilation of Nonradiative Recombination Centers in Polycrystalline Metal Halide Perovskites by Alternating Electric Field and Light

2019

Metal halide perovskites are promising optoelectronic materials. Their electronic properties however are rather unstable which is often assigned to ion migration. Ion migration can be readily influenced by an electric field (EF). Here, the response of photoluminescence (PL) of individual MAPbX3 (MA = CH3NH3, X = I, Br) sub-micrometer-sized polycrystals to EF is studied. Alternating EF with frequency higher than 10 Hz is found to reversibly quench PL. It is proposed that an alternating EF when applied together with light increases ion migration. This leads to a shift in the equilibrium between creation and annihilation of defects toward higher concentration of nonradiative recombination cent…