Sputtered 1-FePd and its Synthetic Antiferromagnet on Si/SiO Wafers for Scalable Spintronics.

As a promising alternative to the mainstream CoFeB/MgO system with interfacial perpendicular magnetic anisotropy (PMA), 1-FePd and its synthetic antiferromagnet (SAF) structure with large crystalline PMA can support spintronic devices with sufficient thermal stability at sub-5 nm sizes. However, the compatibility requirement of preparing 1-FePd thin films on Si/SiO wafers is still unmet. In this paper, we prepare high-quality 1-FePd and its SAF on Si/SiO wafers by coating the amorphous SiO surface with an MgO(001) seed layer.

Measuring the Thickness and Potential Profiles of the Space-Charge Layer at Organic/Organic Interfaces under Illumination and in the Dark by Scanning Kelvin Probe Microscopy.

Scanning Kelvin probe microscopy was used to measure band-bending at the model donor/acceptor heterojunction poly(3-hexylthiophene) (P3HT)/fullerene (C60). Specifically, we measured the variation in the surface potential of C60 films with increasing thicknesses grown on P3HT to produce a surface potential profile normal to the substrate both in the dark and under illumination. The results confirm a space-charge carrier region with a thickness of 10 nm, consistent with previous observations.

Strain effects on the work function of an organic semiconductor.

Establishing fundamental relationships between strain and work function (WF) in organic semiconductors is important not only for understanding electrical properties of organic thin films, which are subject to both intrinsic and extrinsic strains, but also for developing flexible electronic devices. Here we investigate tensile and compressive strain effects on the WF of rubrene single crystals. Mechanical strain induced by thermal expansion mismatch between the substrate and rubrene is quantified by X-ray diffraction.

All-Printed, Foldable Organic Thin-Film Transistors on Glassine Paper.

All-printed, foldable organic thin-film transistors are demonstrated on glassine paper with a combination of advanced materials and processing techniques. Glassine paper provides a suitable surface for high-performance printing methods, while graphene electrodes and an ion-gel gate dielectric enable robust stability over 100 folding cycles. Altogether, this study features a practical platform for low-cost, large-area, and foldable electronics.

Dipole driven bonding schemes of quinonoid zwitterions on surfaces.

The permanent dipole of quinonoid zwitterions changes significantly when the molecules adsorb on Ag(111) and Cu(111) surfaces. STM reveals that sub-monolayers of adsorbed molecules can exhibit parallel dipole alignment on Ag(111), in strong contrast with the antiparallel ordering prevailing in the crystalline state and retrieved on Cu(111) surfaces, which minimizes the dipoles electrostatic interaction energy. DFT shows that the rearrangement of electron density upon adsorption is a result of donation from the molecular HOMO to the surface, and back donation to the LUMO with a concomitant charge transfer that effectively reduces the overall charge dipole.