Nano carbon hybrids: new materials for electronic and biomedical applications Physics Department Florinda Costa & António José Fernandes Nuno Santos & Alexandre Carvalho
Outline 1. Nanocarbon hybrid Materials Carbon Nanotubes / Nanodiamond Graphite / Nanodiamond Graphene / Nanodiamond Biossensors future work 2. Nanocarbons @ University of Aveiro 3. Nanocarbons @ Portugal 2
Carbon allotropes Nobel Prizes a Diamond b Graphite c Lonsdaleite d C60 e C540 f C70 g a-c h CNT I - graphene Fullerenes Graphene 1996 Robert F. Curl Jr. Harold W. Kroto Richard E. Smalley I 2010 Andre Geim Konstantin Novoselov University of Manchester 3
Carbon Nanostructures Physical Properties Diamond CNTs Graphene SWCNT MWCNT Carriers mobility (cm 2 V -1 s -1 ) 4500 (electron) 3800 (hole) 100 000 15 000 (in substrate) 200 000 (suspended) Young Modulus (TPa) Thermal conductivity (W/(K.m) Band Gap (ev) 1 1.5 1 1 2 000 3 000-6 000 600-5 000 Indirect 5.47 (chirality dependent) <2 Metallic behaviour Direct Current density (A/cm 2 ) Insulator 10 9 10 9 0
Carbon Nanostructures Why Hybrid Structures? + + The synergistic combination of different nanocarbons could give rise to materials with improved or even novel properties Is it possible to produce an hybrid material composed by different carbon allotropes? Microwave Plasma CVD reactor (MPCVD) Can they grow simultaneously? Will they form strong bonds? 5 flor@ua.pt
Carbon Nanostructures CNTs Nanodiamond Hybrids + CNT/NCD Hybrid with a neuronal-like network High intercalation between both carbon allotropes obtained by simultaneous MPCVD synthesis High structural quality MWCNTs networks embedded in a NCD matrix CNTs embedded in NCD CNT wrapping NCD CNT through NCD High stiffness High toughness Low resistivity (c.a. 9e -4 Ω.m) Applications: Microelectromechanical systems (MEMS) Cold cathodes for field emission devices (micro X-Ray tubes, displays ) 1 μm 6 flor@ua.pt
Carbon Nanostructures Diamond-graphite nanoplatelets (DNPs) + Vertically-aligned diamond nanoplatelets having conspicuous edges and high aspect-ratio coated with nanographite 100 nm Diamond forms a porous, hard and stiff nanotemplate, while the nanographite coating is responsible for the low electrical resistivity Dark field and energy-filtered TEM analysis: sp 3 bonding of the inner nanowall crystal sp 2 bonding of the surrounding nanographite 100 nm 100 nm 100 nm 10 nm -1 C 7 flor@ua.pt
Carbon Nanostructures DNPs heat dissipation + The dissipation performance of the hybrid material was evaluated under natural convection conditions, using smooth NCD films as reference DNPs vs. NCD: Enhanced convective heat transfer rate due to higher surface area (A): dq/dt A Applications: Efficient thermal management for the miniaturized powerful modern electronic devices Low production cost, weight and thickness Enhanced surface area (10-15 times vs NCD) 8 flor@ua.pt
Carbon Nanostructures DNPs substrates for tissue regeneration + Template for in vitro electrically stimulated proliferation and differentiation studies of preosteoblasts Excellent material to control cellular processes: Biocompatibility, low resistivity (9e -6 Ω.m), enhanced surface area: protein adsorption, cell adhesion DC stimulus: Higher proliferation and mitochondrial activity DC electrical stimulus (3 μa) No DC stimulus: Higher ALP levels (early differentiation) Proliferation Mitochondrial (MTT) Activity Proliferation (cell number/cm 2 ) 60 000 ** * 50 000 40 000 30 000 20 000 10 000 MTT Activity (% of Control) *** 175 * 150 125 100 75 * 50 25 0 C DNPs DC 0 C DNPs DC Alkaline Phosphatase (ALP) Cell Viability 0.35 0.30 ** * 100 ALP Activity (mmol/min/mg protein) 0.25 0.20 0.15 0.10 Viability (%) 80 60 40 0.05 20 9 flor@ua.pt 0.00 C DNPs DC 0 C DNPs DC
Carbon Nanostructures Graphene Nanodiamond Hybrids + A continuous wrinkled graphene film sprinkled with nanocrystalline diamond clusters TEM and Raman confirm the presence of both graphene and diamond Hemispherical clusters Evidence for epitaxy Incommensurate stacking of graphene a) b) c) d) Raman Intensity Intesity (a.u.) TPA Diamond D TPA 10 µm 1 µm 80 nm G D D + D 1000 2000 3000 Raman Shift (cm -1 ) 1000 2000 3000 Raman Shift (cm -1 ) Applications: Good candidates for electronic devices, biosensors and FEDs 2D D+D 2D Theoretical studies: interaction between diamond and graphene can promotes the appearance of a band-gap in graphene 10 flor@ua.pt
Carbon Nanostructures Graphene Nanodiamond Hybrids + The transport properties were analyzed through the transfer curve of field-effect transistors with GDH channels 10 9 Low NCD I 41 35 cm 2 V -1 s -1 7 I 227 28 cm 2 V -1 s -1 10 5 4.5 High NCD I 113 59 cm 2 V -1 s -1 15 I 129 54 cm 2 V -1 s -1 16 1 minute 1 hour 2 hours 8 7 I 40 3 cm 2 V -1 s -1 12 I 113 59 cm 2 V -1 s -1 13 I 245 199 cm 2 V -1 s -1 23 4 3.5 I 37 33 cm 2 V -1 s -1 18 I 118 61 cm 2 V -1 s -1 19 I 76 41 cm 2 V -1 s -1 20 I DS - I 0 ( A) 6 5 4 I DS - I 0 ( A) 3 2.5 2 I 2 24 21 cm 2 V -1 s -1 3 1.5 2 1 1 0.5 0-6 -4-2 0 2 4 6 V (V) GS 0-6 -4-2 0 2 4 6 V (V) GS Measured transferred curve for the long time growth sample I DS ( A) 11 24.1 24 23.9 23.8 23.7-6 -4-2 0 2 4 V (V) GS flor@ua.pt Band gap Expected transfer curve for graphene with gap Low carrier mobility Hydrogenation Structural defects Band gap opening? A potential breakthrough for the development of logical switching devices
Carbon nanostructures Biosensors Future work Nanocarbons as electrodes and sensing platforms in electrochemical sensing devices Amperometric FET Resistive CVD graphene for FET sensing: High quality Low density of defects Easy synthesis and transfer High sensitivity Fast response times Flexible platforms Disposable Nano hybrids for Amperometric and Resistive sensing : Low resistivity High surface area High sensitivity Biocompatibility Simple concept High electrochemical stability Good performance Sensing devices suitable for early diagnosis Easy functionalization 12 flor@ua.pt
Nanocarbons@UA CVD Nanodiamond; CNTs; ALD Hip joint bearings coated with nanocrystalline diamond Vertically aligned CNTs coated with manganese oxide by atomic layer deposition Femoral head + acetabular liner Si 3 N 4 coated with NCD Tested in a 6-station hip joint simulator wear testing machine Before After Raman spectroscopy confirms the structural integrity of VACNTs The extremely low wear rates obtained foresee a life expectancy of more than 100 years >> 10-15 years with conventional materials VACNTs grown on conductive Inconel substrates coated with metal oxides by ALD allows fabricating binder-free electrodes for supercapacitors (EDLC) 13 Group leader: Rui F. Silva rsilva@ua.pt
Nanocarbons@UA Graphene for Smart Textiles Transparent and flexible monolayer Graphene incorporation on textile highly conductive polymer military automotive/ aerospace 1 healthcare wearable functional technology textiles logistics sports fashion commercial potential Textile properties (color, flexibility, ) unchanged High conductivity Sensitivity to some gases 14 Group leader: Helena Alves helena.alves@ua.pt
Nanocarbons @UA Graphene Oxide (GO) Metal nanoparticles@go Polymer functionalized GO as polymer matrix reinforcement GRAPHENE OXIDE (GO) Nano-GO for cell internalization GO foams for heavy metal removal from waste waters TiO 2 -GO membranes for photocatalysis 3D GO/Collagen for TE 15 Group leader: Paula Marques paulam@ua.pt
Nanocarbons@pt
Nanocarbons@pt Nuno Peres Group leader U Porto U Coimbra U Minho U Aveiro Scientific area: Theoretical Physics Nanocarbon forms: graphene Transport properties Electronic properties U Lisboa Plasmonics Director of the Physics Center of University of Minho, he was the first to predict the graphene quantum Hall effect and co-authored the worlds most cited review article on graphene, being one of the most influential scientists in this field. In 2011, Nuno Peres was awarded with the prestigious Gulbenkian Science Prize. 17
Nanocarbons@pt José Luís Figueiredo Group leader U Porto U Coimbra U Minho U Aveiro Scientific area: Catalysis Nanocarbon forms: porous carbon, CNFs and CNTs, GO Photocatalysis Hydrogenation and oxidation U Lisboa Functionalization surface chemistry Jubilated full Professor at the University of Porto (FEUP), member of the scientific board of the journal Carbon. His group are widely recognized in carbons and nanocarbons research. 18
Nanocarbons@pt Cristina Freire Group leader U Porto U Coimbra U Minho U Aveiro Scientific area: Electrochemistry, Catalysis Nanocarbon forms: activated carbon, CNTs, GO functionalization graphene reduction U Lisboa electrochemical sensing She is a full professor at the University of Porto (REQUIMTE/LAQV). Her group have an intense research activity in chemistry nanoscience. 19
Nanocarbons@pt Cristopher Brett Group leader U Porto U Coimbra U Minho U Aveiro Scientific area: (bio)nanoelectrochemistry, Electroanalysis Nanocarbon forms: CNTs, GO functionalization amperometric sensing U Lisboa biosensing electrode design Leading a major reference group in its field, Dr. Brett is a Full Professor at University of Coimbra, fellow of the Royal Society of Chemistry and a member of the Advisory Editorial Board of the journals Electrochimica Acta, Electroanalysis, Analytical Letters and Chinese Journal of Electrochemistry. 20
Nanocarbons@pt C.M. Ferreira (Elena Tatarova) Group leader U Porto U Coimbra U Minho U Aveiro Scientific area: Plasma Physics Nanocarbon forms: graphene microwave plasma synthesis U Lisboa freestanding graphene growth Principal Researcher at the University of Lisboa, she is a member of the Plasma Physics group for a long time under the guidance of C.M. Ferreira, former president of the IST, who recently passed away. In the last few years, this group developed a new plasma process for the substrateless synthesis of few layer graphene sheets. 21
22 Thank you for your attention!