In many years, the Ministry of Science and Technology has been encouraging the scientific research. This research plan is under the long-term support of the Ministry of Science and Technology, Prof. Chun-hsien Chen and Prof. I-Wen Peter Chen have been created to turn surface d bands with bimetallic electrodes to facilitate electron transport across molecular junctions. This outstanding fundamental research result was published in the top journal ⟪ Nature Materials ⟫ in 2021.
Understanding chemical bonding and conductivity at the electrode–molecule interface is key for the operation of single-molecule junctions. Here we apply the d-band theory that describes interfacial interactions between adsorbates and transition metal surfaces to study electron transport across these devices. We realized bimetallic Au electrodes modified with a monoatomic Ag adlayer to connect α,ω-alkanoic acids (HO2C(CH2)nCO2H). The force required to break the molecule–electrode binding and the contact conductance Gn=0 are 1.1 nN and 0.29 G0 (the conductance quantum, 1 G0 = 2e2/h ≈ 77.5 μS), which makes these junctions, respectively, 1.3–1.8 times stronger and 40–60-fold more conductive than junctions with bare Au or Ag electrodes. A similar performance was found for Au electrodes modified by Cu monolayers. By integrating the Newns–Anderson model with the Hammer–Nørskov d-band model, we explain how the surface d bands strengthen the adsorption and promote interfacial electron transport, which provides an alternative avenue for the optimization of molecular electronic devices.
Establishing a solid base of fundamental research is crucial for the future advance of the high-tech industry in Taiwan. The success of thisresearch project also represents a milestone for in the research of fundamental science in Taiwan and meets the objectives of the program.
