A controlled and up-scalable biosynthetic route to nanocrystalline silver particles with well-defined morphology using cell-free aqueous filtrate of a non-pathogenic and commercially viable biocontrol agent Trichoderma asperellum is being reported for the first time. A transparent solution of the cell-free filtrate of Trichoderma asperellum containing 1 mM AgNO(3) turns progressively dark brown within 5 d of incubation at 25 °C. The kinetics of the reaction was studied using UV-vis spectroscopy. An intense surface plasmon resonance band at ∼410 nm in the UV-vis spectrum clearly reveals the formation of silver nanoparticles. The size of the silver particles using TEM and XRD studies is found to be in the range 13-18 nm. These nanoparticles are found to be highly stable and even after prolonged storage for over 6 months they do not show significant aggregation. A plausible mechanism behind the formation of silver nanoparticles and their stabilization via capping has been investigated using FTIR and surface-enhanced resonance Raman spectroscopy.

S2 MethodsReagents. Bismuth nitrate (Bi(NO3)35H2O, Alfa Aesar, 99.9%), selenourea (SeC(NH2)2, Alfa Aesar, 99.9%), potassium hydroxide (KOH, S D Fine-Chem Limited (SDFCL)), sodium hydroxide (NaOH, SDFCL), Disodium EDTA (C10H14O8Na2N2H2O, SDFCL) and ethanol were used without any further purification.Synthesis procedure. 100 mg (0.206 mmol) of Bi(NO3)35H2O, 12.7 mg (0.103 mmol) of SeC(NH2)2 and 306.8 mg (0.824 mmol) of disodium EDTA were sequentially added at a 5 minutes interval into 20 ml water in a glass beaker. The solution was stirred continuously. The addition of Bi(NO3)35H2O into water results in a milky white color solution which turns into an orange color solution after the addition of SeC(NH2)2. The solution becomes clear after the addition of disodium EDTA. Finally, 120 mg (2.14 mmol) of KOH and 320 mg (8 mmol) of NaOH were added into the solution which turns the solution color black. After 10 minutes of stirring, the solution was put to rest which results in precipitation of the dark brown color nanosheets. We observed that nanosheets of similar morphology and thickness can also be obtained without using disodium EDTA, however, in that case, the required amount of water solvent is much higher, 200 ml. These were then washed with alcohol and water and centrifuged to remove disodium EDTA. The purified product was then dried in a vacuum oven at 150 C.Step I: In water, Bi(NO3)3 undergoes hydrolysis to produce BiONO3 and the process of hydrolysis is expedites in alkaline medium:Step II: Selenourea SeC(NH2)2 undergoes decomposition in alkaline medium to generate selenide ions (Se 2-) along with cyanamide (H2NCN): SeC(NH2)2 + OH -→ Se 2-+ H2NCN + H2O

Waste heat sources are generally diffused and provide a range of temperatures rather than a particular temperature. Thus, thermoelectric waste heat to electricity conversion requires a high average thermoelectric figure of merit (ZT ) of materials over the entire working temperature along with a high peak thermoelectric figure of merit (ZT ). Herein an ultrahigh ZT of 1.4 for (GeTe) (AgSbSe ) [TAGSSe-80, T=tellurium, A=antimony, G=germanium, S=silver, Se=selenium] is reported in the temperature range of 300-700 K, which is one of the highest values measured amongst the state-of-the-art Pb-free polycrystalline thermoelectric materials. Moreover, TAGSSe-80 exhibits a high ZT of 1.9 at 660 K, which is reversible and reproducible with respect to several heating-cooling cycles. The high thermoelectric performance of TAGSSe-x is attributed to extremely low lattice thermal conductivity (κ ), which mainly arises due to extensive phonon scattering by hierarchical nano/meso-structures in the TAGSSe-x matrix. Addition of AgSbSe in GeTe results in κ of ≈0.4 W mK in the 300-700 K range, approaching to the theoretical minimum limit of lattice thermal conductivity (κ ) of GeTe. Additionally, (GeTe) (AgSbSe ) exhibits a higher Vickers microhardness (mechanical stability) value of ≈209 kgf mm compared to the other state-of-the-art metal chalcogenides, making it an important material for thermoelectrics.

Core/shell nanocrystal quantum dots (NQDs) have shown great potential as efficient electroluminescent materials in devices like down-conversion phosphors and light-emitting diodes (LEDs). The efficiency of these devices is nonlinearly enhanced by the use of high quantum yield (QY) materials. Though relatively high QY materials with inherent advantages for use in device applications are achieved by thick-shell CdSe/CdS NQDs, their QY is not anywhere near unity due to lack of correlation of the microstructure with their photophysical properties. Here, in this Letter, we show that the control of interfacial defects is crucial to achieve a near-unity QY using microstructure studies of CdSe/CdS NQDs. Simple unoptimized LEDs obtained from these NQDs as the active layer demonstrate performances in excess of 7000 Cd/m 2 with a power conversion efficiency of ∼1.5 lm/W that is comparable to those of the best NQD-based LEDs (1−3%) despite the absence of an electron-injecting buffer layer. SECTION: Physical Processes in Nanomaterials and Nanostructures

Highly transparent, conducting, highly oriented, and almost single phase ZnO films have been deposited by simple e-beam evaporation method, and the deposition parameters were optimized. The films were prepared by (a) evaporation of ZnO at different substrate temperatures and (b) evaporation of ZnO at room temperature and subsequent annealing of the films in oxygen ambient at different temperatures. The characterizations of the film were performed by optical absorption spectroscopy (UV-visible), Fourier transform infrared spectroscopy, resistivity measurement, transmission electron microscopy (TEM), photoluminescence, and x-ray diffraction measurement. Absorption spectra revealed that the films were highly transparent and the band gap of the pre- and postannealed films was in good agreement with the reported values. The band gap of the films increases on increasing the substrate temperature as well as annealing temperature, whereas the resistivity of the film decreases with substrate temperature and increases with annealing temperature. Fourier transform infrared spectroscopy of ZnO films confirms the presence of Zn–O bonding. X-ray diffraction, electron diffraction, and TEM images with high resolution and Raman spectra of the films showed the formation of crystalline ZnO having wurtzite structure