Nanostructured materials for advanced ceramics, photonic devices and polymeric nanofibers Ana Neilde Rodrigues da Silva, Luciana Reyes Pires Kassab, Vanessa Duarte Del Cacho, Davinson Mariano da Silva Faculdade de Tecnologia de São Paulo - Fatec-SP

Introduction We present recent researches developed at Faculdade de Tecnologia de São Paulo related to: Electrospun nanofibers; Nanostructured materials for photonic devices; Advanced ceramics: Alumina nanoparticles via proteic sol-gel Carbon nanotubes obtained from sugarcane bagasse pyrolysis

Electrospinning Laboratório de Circuitos e Dispositivos - Fatec/SP Electrospinning is an easy and low cost process to produce micro and nanofibers from different solution of polymers. This technique has been explored by the researchers aiming the application of the electrospun fibers in several areas. Electrospinning polymeric solution added with black oxide, copper phthalocyanine and starch, resulted in fibers with particles incorporated  membranes for sensitive layer applications Electrospinning apparatus – High Voltage Power Source (0-30 kV, Gama High Voltage), syringe with hypodermic needle

Fibers with Carbon Black The ratio between the solutionsviscosities with and without addition of carbon black is about 3.3. It was possible to determine a relationship between fiber diameter and carbon black concentration. The morphology confirms the particle incorporation into the fiber. A. N. R. Silva and M. L. P. Silva, Nanofibers Selective Membranes Used on Microreactors for Sample Pretreatment,  15th International Meeting on Chemical Sensors (IMCS),2014. Gomes, D. S.; da Silva, A. N. R., The incorporation of carbon black particle into electrospun nanofiber; 29th Symposium on Microelectronics Technology and Devices (SBMicro), 2014; DOI: 10.1109/SBMicro.2014.6940091

Fibers with Copper Phthalocyanine Optical image  particles incorporated as clusters SEM images  rugosities in the fibers suggests the particle incorporation. The fiber diameters increase with the phtalocyanine concentration. SEM image  30.000X Absolute viscosity of PVDF/CuPc solution Diameter vs copper phthalocyanine concentration. D. S. Gomes, A. N. R. da Silva, M. L. P. da Silva, A prospective study of particles incorporation on electrospun fibers aiming at this use as selective membrane, 9th IberoAmerican Congress on Sensors (IBERSENSOR 2014), Bogotá D.C. Colombia.

Fibers with Copper Phthalocyanine Frequency variation in function of ammonia vapor PVDF/CuPc 1:1 w/w PAN/CuPc 1:1 w/w Mass variation in function of PQCs frequency Sauerbrey’s equation: addition of 2.0 mL (1020 ppm NH3) addition of 0,1 mL (51 ppm NH3) PAN/CuPc PVDF/CuPc ∆F (Hz) ∆m (ppb) 20 124.2 31 192.4 14 86.9 17 105.5 9 55.9 11 68.3 6 37.2 12 74.5 Tests with ammonia vapor  the membranes of fibers produced from solutions PAN/CuPc and PVDF/CuPc are promising to be used as sensitive layer and also to detection of gas contaminants and water vapor. D. S. Gomes, A. N. R. da Silva, M. L. P. da Silva, A prospective study of particles incorporation on electrospun fibers aiming at this use as selective membrane, 9th IberoAmerican Congress on Sensors (IBERSENSOR 2014), Bogotá D.C. Colombia.

Fiber morphology and diameter were dependent of the amount of starch in the solution Fibers with Starch Fibers were electrospun on piezoelectric quartz crystals for QCM analysis  PAN/starch fiber as active material for vapour water detection. 10% of relative humidity  water molecules could permeate the PAN chains (probably due to hydrogen bonds formation). crack due to electron desorption  starch as an absorber inside the fiber Fiber diameter in function of starch concentration Relative viscosity in function of starch concentration A N R da Silva et al, Nanofibers and thin films as a selective membrane for sensors and microTAS, Journal of Physics: Conference Series 421 (2013) 012013 doi:10.1088/1742-6596/421/1/012013 QCM Measurements

Influence of gold nanoparticles on the 800 nm optical gain in Tm3+/Yb3+ codoped GeO2-PbO pedestal waveguides Laboratório de Tecnologia em Materiais Fotônicos e Optoeletrônicos - Fatec/SP Pedestal structure was obtained by conventional photolithography and plasma etching; Tm3+/Yb3+ codoped PGO amorphous thin film with gold nanoparticles was obtained by RF Magnetron Sputtering deposition and used as core layer in the pedestal optical waveguide. Yb2O3 and Tm2O3 pellets Shutter with holes GeO2 - PbO target Au target Final profile of Yb3+/Tm3+ doped GeO2-PbO waveguide with gold nanoparticles on the top (pedestal: corrosion of SiO2 film followed by the deposition of the core material). Experimental setup used for gold deposition on the GeO2-PbO waveguide doped with Yb3+/Tm3

TEM micrograph image showing gold nanoparticles (~10 nm diameter). Influence of gold nanoparticles on the 800 nm optical gain in Tm3+/Yb3+ codoped GeO2-PbO pedestal waveguides SEM image of the GeO2-PbO waveguide doped with Yb3+/Tm3 (core of 500nm). TEM micrograph image showing gold nanoparticles (~10 nm diameter).

Influence of gold nanoparticles on the 800 nm optical gain in Tm3+/Yb3+ codoped GeO2-PbO pedestal waveguides Gain enhancement of ~100% (10dB/cm to 22dB/cm) was observed in the presence of gold nanoparticles;  The present results are relevant for the development of optical amplifiers (first telecom window) and can be used in integrated optics in the future with applications for fiber networks of short distances. Optical gain at 800 nm (excitation at 980 nm) as a function of pump power, for 30 μm waveguide width, for the Yb3+/Tm3+ doped GeO2-PbO waveguide with and without gold nanoparticles.

Influence of gold nanoparticles on the 1 Influence of gold nanoparticles on the 1.53 μm optical gain in Er3+ /Yb3+: GeO2 -PbO RIB waveguides Laboratório de Tecnologia em Materiais Fotônicos e Optoeletrônicos - Fatec/SP Rib waveguides: corrosion of the core material after the deposition, instead of the SiO2 substrate, as is the case of the pedestal profile Considering that the range of influence of the gold layer is ≈20 nm, only 1.3% of the GeO2 - PbO thin film is under influence of the gold NPs layer. (a) Schematics showing the details of the waveguide with the gold nanostructured thin film. (b) SEM micrograph of the waveguide with the gold nanolayer of 10 nm. (c) AFM analysis of the waveguide, showing the details of the nanostructured gold layer deposited on the waveguide core. D. M. Da Silva et. al., Optics Express, 22 (13), 16424-16429 (2014).

Influence of gold nanoparticles on the 1 Influence of gold nanoparticles on the 1.53 μm optical gain in Er3+ /Yb3+: GeO2 -PbO RIB waveguides sample with the gold layer: Enhancement factor larger than 400%, for the band at ≈550 nm in the visible region and of ≈30% in the infrared region attributed to the local field growth in the vicinity of the gold nanoparticles. 30 % 400 % near infrared visible Emission spectra of Er3+ /Yb3+ PGO GeO2-PbO thin films under excitation at 980nm in (a) visible and (b) near infrared regions. D. M. Da Silva et. al., Optics Express, 22 (13), 16424-16429 (2014)

Influence of gold nanoparticles on the 1 Influence of gold nanoparticles on the 1.53 μm optical gain in Er3+ /Yb3+: GeO2 -PbO RIB waveguides Gain enhancement of ~100% was observed at 1530 nm (under excitation of 980 nm) in the presence of gold nanoparticles;  The present results are relevant for the development of optical amplifiers (third telecom window). Optical gain as  a function of pump power for waveguide width of 4  µm.  The pump and signal wavelengths were 980 and 1530 nm, respectively. D. M. Da Silva et. al., Optics Express, 22 (13), 16424-16429 (2014)

Laboratório de Síntese de Materiais – Fatec/SP Synthesis of alumina nanoparticles via proteic sol-gel using coconut water Dissolving the salt and sol-gel transformation Produced alumina Filtering coconut water Weighing reagents Drying the gel for 24h (80C) Pre-calcination the xerogel for 4h (500C) Calcination in O2 at 1200°C (3 h) Laboratório de Síntese de Materiais – Fatec/SP The nanocrystalline alumina powders (Al2O3) were produced by proteic sol-gel from the following precursors: Aluminium nitrate nonahydrate (Al(NO3)3.9H2O) and; Coconut water (natural and industrial). The synthesis of alumina employed the precursor salt which was mixed in coconut water (solvent) in the concentrations of 1.50 - 5 mol.L−1; The mass gel was dried in the temperature range of 80C for 24h to obtain the xerogel (dry gel); The dried gel was then pre-calcined at 500C for 4 h and calcined at 1200°C for 3 h (in oxidative atmosphere).

Synthesis of alumina nanoparticles via proteic sol-gel using coconut water The alumina powders were characterized by SEM and AFM, which revealed the Al2O3 nanoparticles with average particle size between 40 to 90 nm; The -Al2O3 (rhombohedral phase) was obtained, as identified by X ray diffraction (XRD). X ray diffractograms of calcined powders using different precursors (natural and industrialized coconut water). D. C. Carvalho, V. D. D. Cacho, XV Brazilian MRS Meeting (SBPMat 2016), in Campinas -SP, September 2016. SEM micrographs of the calcined alumina at 1200°C showing agglomerates and alumina nanoparticles around 50-80 nm. AFM images of alumina produced with natural and industrialized coconut water.

Heating under N2 atmosphere Carbon nanotubes obtained from sugarcane bagasse pyrolysis Laboratório de Processamento e Caracterização de Materiais - Fatec/SP Porous ceramic Substrate (SiC) Metalic film by sputtering Sugarcane bagasse Carbon Nanotubes Heating under N2 atmosphere 10 min/1000°C Or 30 min/1200°C + + Carbon nanotubes growth mechanism

Carbon nanotubes obtained from sugarcane bagasse pyrolysis Preliminary Results Raman Spectroscopy 30 min / 1200°C / N2 10 min / 1000°C / N2

Acknowledgements

Active characterization of the waveguides Laser Sinal: 1530nm / ~ 100 µW Laser Bombeio: 980nm / ~ 100 mW

Active characterization of the waveguide