SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4257-y
Hafnia-based ferroelectrics exhibit a distinctive reverse size effect and exceptional scalability, positioning them as critical candidates for CMOS-compatible non-volatile memory and ferroelectric transistors, with substantial promise for advancing hardware acceleration in artificial intelligence and large-data storage technologies. However, their practical deployment is constrained by a longstanding dilemma: the difficulty in simultaneously stabilizing metastable polar phases and ensuring long-term reliability under the high electric fields required for polarization switching. This review reinterprets this challenge through the lens of defect physics and advocates a paradigm shift from stochastic, disorder-mediated defect incorporation toward ordered, multiscale defect engineering. We systematically discuss the collective influence of point defects, line defects, planar defects, and defect-coupled structures on the phase stability, switching kinetics, and failure mechanisms in hafnia-based ferroelectrics. Controlling oxygen-vacancy states, engineering dopants via Fermi-level and chemical pressure, deploying periodic dislocation arrays, designing topological domain walls, functionalizing interfaces, and leveraging flexoelectric strain gradients constitute the core strategic toolkit. Through such ordered defect architectures, scalable performance metrics, including high remanent polarization, low coercive field, fast switching speed, and endurance exceeding 10^12 cycles, become attainable. These approaches establish a set of design principles for next-generation low-power, high-reliability ferroelectric electronics.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3776-9
Organic thin-film transistors (OTFTs) are fundamental building blocks for flexible electronics, offering mechanical flexibility, biocompatibility, chemical tunability, and compatibility with large-area, cost-effective fabrication. However, their widespread adoption in high-density integrated systems is hindered by the thermionic limit of carrier injection, which constrains the subthreshold swing (SS) to a minimum of 60 mV/dec at room temperature, posing a critical barrier to ultra-low-power operation. In a groundbreaking study published in Nature Electronics, Deng et al. report the realization of organic thin-film tunnel transistors (OTFTTs) that decisively break this Boltzmann tyranny. The breakthrough is enabled by an interfacial molecule decoupling strategy, introducing a high-ionization-energy molecular interlayer, N,N'-bis(2-phenylethyl)perylene-3,4:9,10-tetracarboxylic diimide (BPE-PTCDI), between the high-work-function metal oxide (MoO3) source and the p-type organic semiconductor (2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT)) channel. This interlayer passivates the interface, minimizing interfacial gap states and alleviating Fermi-level pinning, thereby creating a clean heterojunction with a lowered tunneling barrier. This facilitates efficient quantum mechanical band-to-band tunneling for carrier injection at low supply voltages, instead of relying on traditional thermionic emission. The OTFTTs exhibit sub-thermionic SS values below 60 mV/dec, enabling high electrical performance at low operating voltages. This work provides a viable pathway for beyond-thermionic electronics, with potential applications in flexible displays, wearable health monitors, brain-computer interfaces, and distributed sensor networks, addressing the critical challenge of power dissipation in flexible systems.