Search

Conjugated coordination polymers (c‐CPs) are unique organic–inorganic hybrid semiconductors with intrinsically high electrical conductivity and excellent charge carrier mobility. However, it remains a challenge in tailoring electronic structures, due to the lack of clear guidelines. Here, we develop a strategy wherein controlling the redox state of hydroquinone/benzoquinone (HQ/BQ) ligands allows for the modulation of the electronic structure of c‐CPs while maintaining the structural topology. The redox‐state control is achieved by reacting the ligand TTHQ (TTHQ=1,2,4,5‐tetrathiolhydroquinone) with silver acetate and silver nitrate, yielding Ag4TTHQ and Ag4TTBQ (TTBQ=1,2,4,5‐tetrathiolbenzoquinone), respectively. In spite of sharing the same topology consisting of a two‐dimensional Ag−S network and HQ/BQ layer, they exhibit different band gaps (1.5 eV for Ag4TTHQ and 0.5 eV for Ag4TTBQ) and conductivities (0.4 S/cm for Ag4TTHQ and 10 S/cm for Ag4TTBQ). DFT calculations reveal that these differences arise from the ligand oxidation state inhibiting energy band formation near the Fermi level in Ag4TTHQ. Consequently, Ag4TTHQ displays a high Seebeck coefficient of 330 μV/K and a power factor of 10 μW/m ⋅ K2, surpassing Ag4TTBQ and the other reported silver‐based c‐CPs. Furthermore, terahertz spectroscopy demonstrates high charge mobilities exceeding 130 cm2/V ⋅ s in both Ag4TTHQ and Ag4TTBQ. [ABSTRACT FROM AUTHOR]

Linear conjugated polymers have attracted significant attention in organic electronics in recent decades. However, despite intrachain π‐delocalization, interchain hopping is their transport bottleneck. In contrast, two‐dimensional (2D) conjugated polymers, as represented by 2D π‐conjugated covalent organic frameworks (2D c‐COFs), can provide multiple conjugated strands to enhance the delocalization of charge carriers in space. Herein, we demonstrate the first example of thiophene‐based 2D poly(arylene vinylene)s (PAVs, 2DPAV‐BDT‐BT and 2DPAV‐BDT‐BP, BDT=benzodithiophene, BT=bithiophene, BP=biphenyl) via Knoevenagel polycondensation. Compared with 2DPAV‐BDT‐BP, the fully thiophene‐based 2DPAV‐BDT‐BT exhibits enhanced planarity and π‐delocalization with a small band gap (1.62 eV) and large electronic band dispersion, as revealed by the optical absorption and density functional calculations. Remarkably, temperature‐dependent terahertz spectroscopy discloses a unique band‐like transport and outstanding room‐temperature charge mobility for 2DPAV‐BDT‐BT (65 cm2 V−1 s−1), which far exceeds that of the linear PAVs, 2DPAV‐BDT‐BP, and the reported 2D c‐COFs in the powder form. This work highlights the great potential of thiophene‐based 2D PAVs as candidates for high‐performance opto‐electronics. [ABSTRACT FROM AUTHOR]