Fig. 3
From: Charge carrier localised in zero-dimensional (CH3NH3)3Bi2I9 clusters

Photoluminescence (PL) anisotropy of (CH3NH3)3Bi2I9 coating. a Experimental set-up and coating orientation. The detector and incident angle are positioned at right angles and the substrate is rotated to control the angle. The sample is positioned vertically and the wavelength of incident beam is 350 nm. b–d show the respective PL spectra at 25°, 45° and 65°. The black lines at the bottom of b–d are the PL measurement on the bare fused silica substrate at the respective angles