Abstract
We use scanning probe microscopyto study ion migration in formamidinium(FA)-containing halide perovskite semiconductor Cs(0.22)FA(0.78)Pb(I0.85Br0.15)(3) in thepresence and absence of chemical surface passivation. We measure theevolving contact potential difference (CPD) using scanning Kelvinprobe microscopy (SKPM) following voltage poling. We find that ionmigration leads to a & SIM;100 mV shift in the CPD of control filmsafter poling with 3 V for only a few seconds. Moreover, we find thation migration is heterogeneous, with domain interfaces leading toa larger CPD shift than domain interiors. Application of (3-aminopropyl)trimethoxysilane(APTMS) as a surface passivator further leads to 5-fold reductionin the CPD shift from & SIM;100 to & SIM;20 mV. We use hyperspectralmicroscopy to confirm that APTMS-treated perovskite films undergoless photoinduced halide migration than control films. We interpretthese results as due to a reduction in the halide vacancy concentrationafter APTMS passivation.
Rajiv Giridharagopal
Chief scientist at the Ginger lab
Raj is the ‘Cheif Scientist’ and a senior research coordinater at the Ginger lab
David Ginger
B. Seymour Rabinovitch Endowed Chair in Chemistry
David Ginger is the the B. Seymour Rabinovitch Endowed Chair in Chemistry at the University of Washington, and the PI of the ginger group