De novo design of polymers embedded with platinum acetylides towards n-type organic thermoelectrics

To improve the performance of n-type organic thermoelectric (TE) materials still remains great challenge due to the electron trapping and inefficient n-doping. Conducting polymers with dual electronic-ionic transport are promising for TE generators owing to the potential of both large thermoelectric responses and favorable conductivities. However, current progresses are mainly limited to the scanty available p-type polyelectrolytes with inferior electrical properties, which restrict the breakthrough of TE devices. Herein, three π-conjugated polymers with or without the incorporation of platinum acetylides are elaborately designed. Remarkably, the embedded heavy metal atoms can effectively sharpen their density of states nearby the Fermi levels as well as strengthening their through-bond coupling among the metal d-orbitals and the neighboring π-orbitals synchronously. Meanwhile, a simple interfacial modification by using trifluoromethanesulfonic acid is introduced to offer them dual electronic-ionic transport feature. Therefore, a remarkably high thermopower of over −3150 μV K⁻¹ and an enhanced conductivity of 17.1 S m⁻¹ can be achieved by P(TBT-Pt), which is significantly superior to the P(TBTC6) without platinum acetylides. In addition, all these platinum acetylenes exhibit low κ values of around 0.5 W m⁻¹ K⁻¹.