Fig. 4. (a–c) Photographs of the luminescent (a) blue (CsPbClBr₂–PS), (b) green (CsPbBr₃–PS) and (c) red (CsPbBrI₂–PS) composites prepared with no ligand (left), one ligand (middle) or two ligands (right), under UV excitation. All photos are taken with identical camera exposure settings. (d–f) Comparison of PL emission spectra and relative PL intensities of (d) blue (CsPbClBr₂–PS), (e) green (CsPbBr₃–PS) and (f) red (CsPbBrI₂–PS) composites prepared with no ligand (black line), one ligand (blue line) or two ligands (red line).