Color Turning of One-Dimensional Broadband Emissive Organic Lead Bromide Perovskites

To determine the important structural factors affecting the broadband fluorescence colors of one-dimensional (1D) perovskite materials, a comparative study is carried out in this work. Two 1D organic lead bromide perovskites are synthesized, i.e., ppPbBr3 and bpPbBr3, using phenyl pyrrolidine and benzyl pyrrolidine as the ligands, respectively. Just by changing the A site cations, the octahedral lead bromide structure in ppPbBr3 is a Jahn–Teller distortion structure, while those in bpPbBr3 is an off-centering structure. All of these octahedra form 1D straight lines via face-sharing. PpPbBr3 and bpPbBr3 exhibit broadband photofluorescence centered at 570 and 720 nm, respectively. Considering that their apparent band gaps are close, the off-centering octahedral structure has a stronger trapping energy to excitons than does the Jahn–Teller distortion structure. Our work shows that octahedral distortion is a key structural factor realizing color modulation of broadband fluorescence in these 1D perovskites.