Room Temperature Mid-IR Detection through Localized Surface Vibrational States of SnTe Nanocrystals.

Quantum dots (QDs) are now well established as promising materials for room temperature mid-infrared (MIR) detection beyond 3 µm. Here, we have replaced commonly reported mercury based quantum dots with less toxic SnTe and PbSnTe. Inverse MIR detection at room temperature is demonstrated with planar, solution, and air-processed PbSnTe and SnTe QD devices. The detection mechanism is shown to be mediated by an interaction between MIR radiation and the vibrational stretches of adsorbed hydroxyl species. Devices are shown to possess mA/W responsivity via a reduction in conductance due to MIR irradiation and, unlike classic MIR photoconductors, are unaffected by visible wavelengths. As such, these devices offer the possibility of MIR thermal imaging that has an intrinsic solution to the blinding caused by higher energy light sources.

Photo-Electrosensitive Memristor Using Oxygen Doping in HgTe Nanocrystal Films.

Nanocrystal-based electronic devices with multiple functionalities offer one avenue toward novel passive and active electronic components. Here, we exhibit a planar and fully air-processed thin film device that demonstrates a photoinduced memristive behavior and can be used as a transistor, photodetector, or memory device. Following long-term (60 h) air exposure, unpackaged nanocrystal films develop reliable memristive characteristics in tandem with temperature, gate, and photoresponse. The on/off values of more than 50 are achieved, and the devices show long-term stability, producing repeatable metrics over days of measurement. The on/off behavior is shown to be dependent on the previous charge flow and carrier density, implying a memristive rather than switching behavior. These observations are described within a long-term trap-filling model. This work represents an advance in the integration of nanocrystal films into electronic devices, which may lead to the development of multifunctional electronic components.

Isolation and identification of compounds from Kalanchoe pinnata having human alphaherpesvirus and vaccinia virus antiviral activity.

CONTEXT: Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) is a succulent plant that is known for its traditional antivirus and antibacterial usage. OBJECTIVE: This work examines two compounds identified from the K. pinnata plant for their antivirus activity against human alphaherpesvirus (HHV) 1 and 2 and vaccinia virus (VACV). MATERIALS AND METHODS: Compounds KPB-100 and KPB-200 were isolated using HPLC and were identified using NMR and MS. Both compounds were tested in plaque reduction assay of HHV-2 wild type (WT) and VACV. Both compounds were then tested in virus spread inhibition and virus yield reduction (VYR) assays of VACV. KPB-100 was further tested in viral cytopathic effect (CPE) inhibition assay of HHV-2 TK-mutant and VYR assay of HHV-1 WT. RESULTS: KPB-100 and KPB-200 inhibited HHV-2 at IC50 values of 2.5 and 2.9 µg/mL, respectively, and VACV at IC50 values of 3.1 and 7.4 µg/mL, respectively, in plaque reduction assays. In virus spread inhibition assay of VACV KPB-100 and KPB-200 yielded IC50 values of 1.63 and 13.2 µg/mL, respectively, and KPB-100 showed a nearly 2-log reduction in virus in VYR assay of VACV at 20 µg/mL. Finally, KPB-100 inhibited HHV-2 TK- at an IC50 value of 4.5 µg/mL in CPE inhibition assay and HHV-1 at an IC90 of 3.0 µg/mL in VYR assay. DISCUSSION AND CONCLUSION: Both compounds are promising targets for synthetic optimization and in vivo study. KPB-100 in particular showed strong inhibition of all viruses tested.