Benzotrithiophene-based MOFs: interchromophoric interactions affected Ln(III) crystallization selectivity and optoelectronic properties.

Metal-organic frameworks (MOFs) provide an ideal platform for the assembly of chromophores and thus show wide potential application in optoelectronic devices. The spatial arrangement and interaction of the incorporated chromophores play a key role in the generation of coherent optical and electronic properties. In this work, two series of benzo-(1,2;3,4;5,6)-tristhiophene (BTT) based Ln-MOFs (Ln-1s and Ln-2s) were synthesized. These two series of MOFs present different assembly states of BTT chromophores, that is, BTT containing ligands exist as separated monomers in Ln-1s but gather as dimers in Ln-2s. Through the comparison between these two series of MOFs and theoretical calculation, we show for the first time that this chromophore assembly state difference could affect the crystallization selectivity of MOF towards different Ln3+ ions. Additionally, the interaction between BTT chromophores in the dimer also leads to the red-shifted photoluminescence and enhanced photocurrent of Ln-2s relative to those of Ln-1s. The results of this work demonstrate the multi-function of interchromophoric interaction on the structures and optoelectronic properties of MOFs.