(a) Cross-sectional scanning electron microscope (SEM) image of 270-nmthick
mixed halide CH3NH3PbI3xClx absorber layer with hole-quenching
layer of spiro-OMeTAD. (b) Photoluminescence (PL) data of one-dimensional
diffusion model (described in Ref. [20]) for mixed halide CH3NH3PbI3xClx
and (c) 180 nm-thick triiodide CH3NH3PbI3 in the presence of electronquencher
PCBM and hole-quencher spiro-MeOTAD without any quenchers
(PMMA). (Inset) Comparison of recombination life time of two perovskites
(with PMMA). Reprinted from Ref. [20].