Gratings, one of the most important energy dispersive devices, are the fundamental building blocks for the majority of optical and optoelectronic systems. The grating period is the key parameter that limits the dispersion and resolution of the system. With the rapid development of large X-ray science facilities, gratings with periodicities below 50 nm are in urgent need for the development of ultrahigh-resolution X-ray spectroscopy. However, the wafer-scale fabrication of nanogratings through conventional patterning methods is difficult. Herein, we report a maskless and high-throughput method to generate wafer-scale, multilayer gratings with period in the sub-50 nm range. They are fabricated by a vacancy epitaxy process and coated with X...[ Learn more ]

Graphene nanobubbles (GNBs) have attracted much attention due to the ability to generate large pseudo-magnetic fields unattainable by ordinary laboratory magnets. However, GNBs are always randomly produced by the reported protocols, therefore, their size and location are difficult to manipulate, which restricts their potential applications. Here, using the functional atomic force microscopy (AFM), we demonstrate the ability to form programmable GNBs. The precision of AFM facilitates the location definition of GNBs, and their size and shape are tuned by the stimulus bias of AFM tip. With tuning the tip voltage, the bubble contour can gradually transit from parabolic to Gaussian profile. Moreover, the unique threefold symmetric pseudo-magn...[ Learn more ]

The stability of pure organic room-temperature phosphorescent (RTP) materials in air has been a research hotspot in recent years. Without crystallization or encapsulation, a new strategy was proposed to obtain self-stabilized organic RTP materials, based on a complete ionization of a photo-induced charge separation system. The ionization of aromatic phenol 4-carbazolyl salicylaldehyde (CSA) formed a stable H-bonding anion–cation radical structure and led to the completely amorphous CSA-I film. Phosphorescent lifetimes as long as 0.14 s at room temperature and with direct exposure to air were observed. The emission intensity was also increased by 21.5-fold. Such an amorphous RTP material reconciled the contradiction between phosphorescen...[ Learn more ]

Physically transient optics, a form of optics that can physically disappear with precisely controlled degradation behaviors, has widespread applications including information security, drug release, and degradable implants. Here, a set of silk-based programmable vanishing, biologically functional, multichromatic diffractive optical elements (MC-DOEs) is reported. Silk proteins produced by silkworms and spiders are mechanically robust, biocompatible, biodegradable, and importantly, optically transparent, which open up new opportunities for a set of fully degradable transient optical devices with no need of metallic or semiconductor components. Compared with monochromatic DOEs, MC-DOEs carry out richer information for more practical applic...[ Learn more ]

Epidermal sensing devices offer great potential for real-time health and fitness monitoring via continuous characterization of the skin for vital morphological, physiological, and metabolic parameters. However, peeling them off can be difficult and sometimes painful especially when these skinmounted devices are applied on sensitive or wounded regions of skin due to their strong adhesion. A set of biocompatible and water-decomposable “skinfriendly” epidermal electronic devices fabricated on flexible, stretchable, and degradable protein-based substrates are reported. Strong adhesion and easy detachment are achieved concurrently through an environmentally benign, plasticized protein platform offering engineered mechanical properties and w...[ Learn more ]