Fig. 2. Laterally measured PL and EL of perovskite.
a Schematic representation of spatially resolved PL measurements with separate microscope objectives for excitation and collection. Trapped photons become detectable by either PR or scattering. b Laterally measured PL (normalised) as a function of distance from the point-of-excitation at wavelengths of 505 (± 5) nm and 525 (± 5) nm for a 2D–3D mixture PEA2Csn–1PbnBr3n+1 perovskite film with a gap between 230 μm and 290 μm. The measured PL intensity was multiplied by distance to compensate for the radial spread of light intensity, to give an indication of photon losses as a function of distance. c Measured PL spectra at distances of 0 μm (O, initial excitation), 265 μm (A, where perovskite was removed), 290 μm (B, at the edge of the gap) and 310 μm (C, on perovskite). d Normalised spatial EL for a full device, where voltage (4 V) is applied to the pixel covering from −1500 μm to 0 μm. (inset: the measured EL spectra in A.U. at 0 μm and 1800 μm). The schematic shows possible ray paths in the substrate.