Fluorescence imaging in the near-infrared II (NIR-II, 1000–1700 nm) region opens up new avenues for biological systems due to suppressed scattering and low autofluorescence at longer-wavelength photons. Nonetheless, the development of organic NIR-II fluorophores is still limited mainly due to the shortage of efficient molecular design strategy. Herein, we propose an approach of designing Janus NIR-II fluorophores by introducing electronic donors with distinct properties into one molecule. As a proof-of-concept, fluorescent dye 2 TT- m, o C6B with both twisted and planar electronic donors displayed balanced absorption and emission which were absent in its parent compound. The key design strategy for Janus molecule is that it combines the merits of intense absorption from planar architecture and high fluorescence quantum yield from twisted motif. The resulting 2 TT- m, o C6B nanoparticles exhibit a high molar absorptivity of 1.12 ⨯10 4 M −1 cm −1 at 808 nm and a NIR-II quantum yield of 3.7%, displaying a typical aggregation-induced emission (AIE) attribute. The highly bright and stable 2 TT- m, o C6B nanoparticles assured NIR-II image-guided cancer surgery to resect submillimeter tumor nodules. The present study may inspire further development of molecular design philosophy for highly bright NIR-II fluorophores for biomedical applications.

Traditional RF-based indoor positioning approaches use only Radio Signal Strength Indicator (RSSI)to locate the target object. But RSSI suffers significantly from the multi-path phenomenon and other environmental factors. Hence, the localization accuracy drops dramatically in a large tracking field. To solve this problem, this paper introduces one more resource, the dynamic of RSSI, which is the variance of signal strength caused by the target object and is more robust to environment changes. By combining these two resources, we are able to greatly improve the accuracy and scalability of current RF-based approaches. We call such hybrid approach COCKTAIL. It employs both the technologies of active RFID and Wireless Sensor Networks (WSNs). Sensors use the dynamic of RSSI to figure out a cluster of reference tags as candidates. The final target location is estimated by using the RSSI relationships between the target tag and candidate reference tags. Experiments show that COCKTAIL can reach a remarkable high degree of localization accuracy to 0.45m, which outperforms significantly to most of the pure RFbased localization approaches.

A high-temperature (180 o C) gate recess technique featuring low damage and in-situ self-clean capability, in combination with O 3 -assisted atomic-layer-deposition (ALD) of Al 2 O 3 gate dielectric, is developed for fabrication of high performance normally-off AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs), which exhibit a threshold voltage of +1.6 V, a pulsed drive current of 1.1 A/mm, and low dynamic ON-resistance under hard-switching operation. Chlorine-based dry-etching residues (e.g. AlCl 3 and GaCl 3 ) are significantly reduced by increasing the wafer temperature during the gate recess to their characteristic desorption temperature, while defective bonds like Al-O-H and positive fixed charges in ALD-Al 2 O 3 are significantly suppressed by substitution of H 2 O with O 3 precursor.