Zernike seminar: Yuzhong Hu "Hybrid Molecular Ferroelectrics, A New Path for Outstanding Electromechanical and Photoelectric Properties for Polar Materials"

Ferroelectrics are materials with switchable spontaneous electric polarization, enabling them to manipulate their photoelectric properties and generate charge in response to mechanical strain and vice versa. These promise ferroelectrics as logical photoelectric devices, electromechanical sensors and energy harvesters. Hybrid molecular ferroelectrics (HMFs) is an emerging class of ferroelectrics comprise both organic and inorganic components as building blocks. This distinctive configuration makes HMFs possess unique approach for exceptional electromechanical and photoelectric properties at both bulk and nanoscale level. In the electromechanical section of my report, I will present the innovative molecular engineering strategy we utilized to induce giant strain output (22%, ~ 0.5% in conventional ferroelectrics), large piezoelectric responses (4800 pm/V, ~ 50 pm/V for general polymer), promising energy harvesting performance and remarkable mechanical softness in HMFs. The photoelectric section will highlight our discovery of the survived ferroelectricity and great photoelectric robustness in 2D HMFs down to the monolayer limit, which are rarely observed in traditional ferroelectrics. The structural and compositional origin for these outstanding properties at the nanoscale will also be disclose and analyzed.