Optical properties of natural quantum-well compounds (C6H5-CnH2n-NH3)2PbBr4 (n=1–4)

This paper describes the synthesis and characterization of self-assembled organic–inorganic layered perovskite compounds, (C6H5-CnH2n-NH3)2PbBr4 (n=1–4). the effect of the number of carbon atoms of the alkyl chain length (n) on optical properties has been studied. (C6H5-CnH2n-NH3)2PbBr4 films fabricated by spin-coating are microcrystalline form, single phase and oriented with the c-axis. Crystallinity, the maximum PL intensity and the lifetime of exciton emissions varied with the number of carbon atoms. the lowest-energy exciton splits into a few fine-structure levels at low temperatures. Time-resolved photoluminescence spectra reveal that (C6H5-CnH2n-NH3)2PbBr4 shows both singlet and triplet excitons. with decreasing temperature, triplet exciton emissions become dominant for (C6H5-CnH2n-NH3)2PbBr4 (n=1–3), while (C6H5-C4H8-NH3)2PbBr4 shows mainly singlet exciton emissions. The intersystem crossing from excited singlet state to triplet state plays an important role in the relaxation process of excitons.