Dynamic, conjugated microporous polymers: visible light harvesting via guest-responsive reversible swelling

The light-harvesting properties of two fluorescent dynamic conjugated microporous organic polymers (Py-PP and Py-BPP) rendered with pyrene chromophores are described. The hydrophobic and dynamic nature of these porous frameworks allows the selective capture of various organic solvents by instantaneous swelling at room temperature. Moreover, the dynamic nature of these frameworks indicates the swelling process with visible volume expansion and enhanced fluorescence. This was further explored for the rapid encapsulation of various fluorescent chromophoric guests at room temperature and investigated for photoinduced energy transfer process. The resultant host-guest antenna materials showed efficient light-harvesting and funnelling of excitation energy of host framework towards the entrapped guest molecule. This process further yielded solid-state luminescent materials with tunable emission. This work holds a great promise on the design of smart porous organic solids from π-conjugated small molecules for optoelectronics, sensing and separation.