Polakovsky Anastazia, Showman Janai, Valdiviezo Jesús, Palma Julio L
Department of Chemistry, The Pennsylvania State University, Fayette, The Eberly Campus, Lemont Furnace, Pennsylvania 15456, USA.
Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
Phys Chem Chem Phys. 2021 Jan 21;23(2):1550-1557. doi: 10.1039/d0cp05801g.
We present a theoretical and computational work and demonstrate that cross-conjugated molecules with electron-donating groups are efficient rectifiers with high conductance. The rectification ratios obtained are up to one order of magnitude at an applied bias voltage of 0.3 V. The use of electron-withdrawing groups to form donor-bridge-acceptor triads gives rectification ratios of the order of 102. We found that the high rectification results from localizing the Highest Occupied Molecular Orbital (HOMO) at one end of the molecular device. When the HOMO is localized, quantum interference effects substantially enhance rectification. Our observations rely on transport calculations of linearly-conjugated and cross-conjugated molecules using Non-Equilibrium Green's Function Technique and Density Functional Theory (NEGF-DFT). Analysis of transmission functions suggests a dependency of the rectification ratio on the anti-resonance peak position near the Fermi level of the electrode, allowing the possibility to modulate molecular rectification through electrochemical gating.
我们展示了一项理论和计算工作，并证明带有供电子基团的交叉共轭分子是具有高电导率的高效整流器。在0.3 V的外加偏置电压下，获得的整流比高达一个数量级。使用吸电子基团形成供体-桥-受体三元组可得到102量级的整流比。我们发现，高整流率源于分子器件一端的最高占据分子轨道（HOMO）的局域化。当HOMO局域化时，量子干涉效应会显著增强整流效果。我们的观察结果依赖于使用非平衡格林函数技术和密度泛函理论（NEGF-DFT）对线性共轭和交叉共轭分子进行的输运计算。对传输函数的分析表明，整流比依赖于电极费米能级附近的反共振峰位置，这使得通过电化学门控调节分子整流成为可能。
