Fig. 2. XPS spectra of Sn 3d3/2 and 3d5/2 core levels for the (a) control, (b) TM-DHP-treated, and (c) TM-DHP combined with maltol treated perovskite films. The amount of Sn(iv) content on the surface of the control, TM-DHP, and both TM-DHP and maltol treated perovskite films is 9, 6, and 3%, respectively. (d) XRD patterns of perovskite films fabricated on PEDOT:PSS-coated FTO substrates. (e) Steady-state photoluminescence (PL) spectra, and (f) time-resolved photoluminescence (TRPL) decay curves of the perovskite films fabricated on quartz substrates. The carrier lifetime of the control, TM-DHP, and both TM-DHP and maltol treated perovskite films is 1.3, 3.7, and 7.4 μs, respectively.
