Postsynthetic-Modified PANI/MOF Composites with Tunable Thermoelectric and Photoelectric Properties.

A 3D Co-based metal-organic framework (Co-MOF) with two kinds of large pores filled by free Co ions and ligands was synthesized and characterized. To expand the MOF structure and conductivity, the free Co ions and ligands were exchanged by conductive ionic liquid EtpyBr and photosensitive AgNO through single crystal-to-single crystal transformation, which produced structure-changed 3D MOFs Co-MOF-Br and Co-Ag-MOF, which were characterized by single-crystal X-ray diffraction. Incorporating small quantities of doped polyaniline (PANI) with redox activity into the pores could further tune the stability and conductivity of the three MOFs. The PANI/MOFs all show outstanding electrical conductivity (≈10  S cm ), and PANI/Co-MOF-Br has the largest p-type Seebeck coefficient of 66.6 μV K . PANI/Co-MOF-Br and PANI/Co-Ag-MOF have 4 and 15 times higher photocurrent density compared with PANI/Co-MOF, respectively. This work sheds light on the design of advanced electrically conductive 3D MOFs.