In this thesis the properties of graphene and its few-layers are engineered to make them highly conductive. Two different approaches were implemented to achieve this goal. One approach was to increase the concentration of charge carriers by intercalation of acceptor FeCl3 molecules between graphene planes. This resulted in a highly conductive yet transparent material which can be useful for applications. Another approach was to increase the mobility of carriers by means of removing surface contamination in the current annealing process. Optimal annealing parameters were found and a reproducible cleaning method was suggested.

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In the past decade, rechargeable batteries attracted the attention from the researchers in search for renewable and sustainable energy sources. Up to date, lithium-ion battery is the most commercialized and has been supplying power to electronic devices and hybrid and electric vehicles. Lithium-ion battery, however, does not satisfy the expectations of ever-increasing energy and power density, which of their limits owes to its intercalation chemistry and the safety.1-2 Therefore, metal-air battery drew much attention as an alternative for its high energy density and a simple cell configuration.1 There are several different types of metal-air batteries that convey different viable reaction mechanisms depending on the anode metals; such as Li, Al, Ca, Cd, and Zn. Redox reactions take place in a metal-air cell regardless of the anode metal; oxidation reaction at the anode and reduction reaction at the air electrode. Between the two reaction, the oxygen reduction reaction (ORR) at the air electrode is the relatively the limiting factor within the overall cell reactions. The sluggish ORR kinetics greatly affects the performance of the battery system in terms of power output, efficiency, and durability. Therefore, researchers have put tremendous efforts in developing highly efficient metal air batteries and fuel cells, especially for high capacity applications such as electric vehicles. Currently, the catalyst with platinum nanoparticles supported on carbon material (Pt-C) is considered to exhibit the best ORR activities. Despite of the admirable electrocatalytic performance, Pt-C suffers from its lack of practicality in commercialization due to their prohibitively high cost and scarcity as of being a precious metal. Thus, there is increasing demand for replacing Pt with more abundant metals due economic feasibility and sustainability of this noble metal.3-5 Two different attitudes are taken for solution. The first approach is by optimizing the platinum loading in the formulation, or the alternatively the platinum can be replaced with non-precious materials. The purpose of this work is to discover and synthesize alternative catalysts for metal-air battery applications through optimized method without addition of precious metals. Different non-precious metals are investigated as the replacement of the precious metal including transition metal alloys, transition metal or mixed metal oxides, and chalcogenides. These types of metals, alone, still exhibits unsatisfying, yet worse, kinetics in comparison to the precious metals. Nitrogen-doped carbon material is a recently well studied carbon based material that exhibits great potential towards the cathodic reaction.6 Nitrogen-doped carbon materials are found to exhibit higher catalytic activity compared to the mentioned types of metals for its improved conductivity. Benefits of the carbon based materials are in its abundance and minimal environmental footprints. However, the degradation of these materials has demonstrated loss of catalytic activity through destruction of active sites containing the transition metal centre, ultimately causing infeasible stability. To compensate for these drawbacks and other limits of the nitrogen-doped carbon based catalysts, nitrogen-doped carbon nanotubes (NCNT) are also investigated in the series of study. The first investigation focuses on a development of a simple method to thermally synthesize a non-precious metal based nitrogen-doped graphene (NG) electrocatalyst using exfoliated graphene (Ex-G) and urea with varying amounts of iron (Fe) precursor. The morphology and structural features of the synthesized electrocatalyst (Fe-NG) were characterized by SEM and TEM, revealing the existence of graphitic nanoshells that potentially contribute to the ORR activity by providing a higher degree of edge plane exposure. The surface elemental composition of the catalyst was analyzed through XPS, which showed high content of a total N species (~8 at.%) indicative of the effective N-doping, present mostly in the form of pyridinic nitrogen groups. The oxygen reduction reaction (ORR) performance of the catalyst was evaluated by rotating disk electrode voltammetry in alkaline electrolyte and in a zinc-air battery cell. Fe-NG demonstrated high onset and half-wave potentials of -0.023 V (vs. SCE) and -0.110 V (vs. SCE), respectively. This excellent ORR activity is translated into practical zinc-air battery performance capabilities approaching that of commercial platinum based catalyst. Another approach was made in the carbon materials to further improve the cost of the electrode. Popular carbon allotropes, CNT and graphene, are combined as a composite (GC) and heteroatoms, nitrogen and sulfur, are introduced in order to improve the charge distribution of the graphitic network. Dopants were doped through two step processes; nitrogen dopant was introduced into the graphitic framework followed by the sulfur dopant. The coexistence of the two heteroatoms as dopants demonstrated outstanding ORR performance to those of reported as metal free catalysts. Furthermore, effects of temperature were investigated through comparing ORR performances of the catalysts synthesized in two different temperatures (500 ??? and 900 ???) during the N-doping process (consistent temperature was used for S-doping). Through XPS analysis of the surface chemistry of catalysts produced with high temperature during the N-doping step showed absence of N-species after the subsequent S-doping process (GC-NHS). Thus, the synergetic effects of the two heteroatoms were not revealed during the half-cell testing. Meanwhile, the two heteroatoms were verified in the catalyst synthesized though using low temperature during the N-doping process followed by the S-doping step (GC-NLS). Consequently, ORR activity of the resulting material demonstrated promising onset and half-wave potentials of -0.117 V (vs. SCE) and -0.193 V (vs. SCE). In combination of these investigations, this document introduces thorough study of novel materials and their performance in its application as ORR catalyst in metal air batteries. Moreover, this report provides detailed fundamental insights of carbon allotropes, and their properties as potential elecrocatalysts and essential concepts in electrochemistry that lies behind zinc-air batteries. The outstanding performances of carbon based electrocatalyst are reviewed and used as the guides for further direction in the development of metal-air batteries as a promising sustainable energy resource in the future.

In the last three decades carbon nanomaterials such as fullerenes, carbon nanotubes and graphene have attracted significant attention from the scientific community due to their unique electronic, optical, thermal, mechanical and chemical properties. Among them carbon nanotubes and graphene have been used in numerous applications for future nanoelectronics, biochemical sensors and energy harvesting technologies due to their unique properties including exceptionally high electronic conductivity and mechanical strength. Carbon nanotubes are cylindrical structures and considered to be large mesoscopic molecules with high aspect ratios. Graphene is a single atomic layer of crystalline graphite and prepared by stripping layers off the graphite using Scotch tape. Apart from this scotch tape method, chemical ex-foliation and reduction of graphite oxide produces large amounts of reduced graphene oxide which has similar properties as graphene. This thesis reports on the biosensors made of reduced graphene oxide and single walled carbon nanotubes based on their electronic properties. We also demonstrate the changes in electronic properties of single walled carbon nanotubes due to interactions with dendrimer molecules. Finally, the yielding and flow behaviour of graphene oxide nematic gel are discussed. Chapter 1 gives a general introduction about the preparation and characterization along with the electronic properties of the systems studied in this thesis, namely graphene oxide, reduced graphene oxide and single walled carbon nanotubes. We have also discussed about the experimental techniques such as Raman, UV-visibe and infrared spectroscopy, atomic force and scanning tunneling microscopy and different types of rheometers used in this thesis work. In Chapter 2, we discuss top-gated field effect transistor characteristics of the devices made of reduced graphene oxide monolayer by dielectrophoresis. Raman spectrum of RGO flakes shows a single 2D band at 2687 cm 1, characteristic of a single layer graphene. The two probe current - voltage measurements of RGO flakes, deposited in between the patterned electrodes using a.c. dielectrophoresis show ohmic behavior with a resistance of 37kΩ. The temperature dependence of the resistance (R) of RGO measured between temperatures 305K to 393K yields the temperature coefficient of resistance of -9.5 10 4/K. Ambipolar nature of graphene flakes is observed upto a doping level of 6 1012/cm2 and carrier mobility of 50cm2/V-sec. The source - drain current characteristics shows a tendency of current saturation at high source - drain voltage which is analyzed quantitatively by a diffusive transport model. In Chapter 3, We demonstrate the detection of glucose molecules by using reduced graphene oxide (RGO) and aminophenylboronic acid (APBA) complex with detection limit of 5 nM. APBA functionalized RGO (APBA-RGO) flakes, prepared by stirring the aqueous GO suspension in the presence of APBA molecules at 100◦C, were used as conducting channel in our field effect transistor (FET) devices. The APBA-RGO complex formation was confirmed by atomic force microscopy (AFM), x - ray photoelectron, Raman and UV-visible spectroscopic studies. Detection of glucose molecules was carried out by monitoring the changes in electrical conductance of the APBA-RGO flake in the FET device. FET devices made of non-covelently functionalized APBA-RGO complex (nc-APBA-RGO) exhibited enhanced sensitivity over the devices made of covalently functionalized APBA-RGO complex (c-APBA-RGO). Change in normalized conductance in the FET devices made of nc-APBA-RGO flakes ( 85%) is 4 times more than that of in the devices made of c-APBA-RGO flakes in response to aqueous glucose solution with different concentrations. Specificity of APBA-RGO complex to glucose was proved from the observation of negligible change in electrical conductance of the FET devices made of nc-APBA-RGO complex after exposure to 10 mM lactose solution. Chapter 4 reports unipolar resistive switching in ultrathin films of chemically produced graphene (reduced graphene oxide) and multiwalled carbon nanotubes. The two - terminal devices with yield > 99% are made at room temperature by forming continuous films of graphene of thickness 20 nm on indium tin oxide coated glass electrode, followed by metal (Au or Al) deposition on the lm. These memory devices are non - volatile, rewritable with ON/OFF ratios up to 105 and switching times up to 10 s. The devices made of MWNT films are rewritable with ON/OFF ratios up to 400. The resistive switching mechanism is proposed to be nanogap formation. In the first part of Chapter 5, we study the interactions between SWNT and PETIM dendrimer by measuring the quenching of inherent fluorescence of the dendrimer. Also, the dendrimer - nanotube binding results in the increased electrical resistance of the hole-doped SWNT due to charge transfer interaction between the dendrimer and the nanotube. This charge transfer interaction was further corroborated by observing a shift in frequency of the tangential Raman modes of SWNT. Experimental studies were supplemented by all atom molecular dynamics simulations to provide a microscopic picture of the dendrimer - nanotube complex. The complexation was achieved through charge - transfer and hydrophobic interactions, aided by multitude of oxygen, nitrogen and n-propyl moieties of the dendrimer. We also studied the effect of acidic and neutral pH conditions on the binding affinities. In the second part, we show that SWNT decorated with sugar functionalized PETIM dendrimer is a very sensitive platform to quantitatively detect carbohydrate recognizing proteins, namely, lectins. The changes in electrical conductivity of SWNT in field effect transistor device due to carbohydrate - protein interactions forms the basis of this study. The mannose sugar attached PETIM dendrimers undergo charge - transfer interactions with the SWNT. The changes in the conductance of the dendritic sugar functionalized SWNT after addition of lectins in varying concentrations were found to follow the Langmuir type isotherm, giving the concanavalin A (Con A) - mannose affinity constant to be 8.5 106 M-1. The increase in the device conductance observed after adding 10 nM of Con A is same as after adding 20 µM of a non - specific lectin peanut agglutinin, showing the high specificity of the Con A - mannose interactions. The specificity of sugar-lectin interactions was characterized further by observing significant shifts in Raman modes of the SWNT. Chapter 6 reports the metal to semiconductor transition in metallic single-wall carbon nanotubes (SWNT) due to the wrapping of mannose attached poly (propyl ether imine) dendrimer (DM) molecule. Scanning tunneling spectroscopic (STS) measurements and ionic liquid top gated field effect transistor (FET) characteristics of the nanotube-dendrimer complex gives a band gap of 0.42eV, close to the E11 energy gap between the first van Hove singularities of 1.7nm diameter semiconducting nanotubes. The absence of Breit-Wigner-Fano (BWF) component in G band in the Raman spectrum of the nanotube-dendrimer complex corroborates the semiconductor nature of the tubes after wrapping with the dendrimer molecules. Dendrimer molecule breaks the symmetry in metallic SWNT by wrapping around it through the charge transfer interactions. In the first part of Chapter 7, we demonstrate a rigidity percolation transition and the onset of yield stress in a dilute aqueous dispersion of graphene oxide platelets (aspect ratio 5000) above a critical volume fraction of 3.75x10-4 with a percolation exponent of 2.4 ± 0.1.The viscoelastic moduli of the gel at rest measured as a function of time indicates the absence of structural evolution of the 3D percolated network of disks. However, a shear-induced aging giving rise to a compact jammed state and shear rejuvenation indicating a homogenous flow is observed when a steady shear stress (σ ) is imposed in creep experiments. We construct a shear diagram (σ vs volume fraction ϕ) and the critical stress above which shear rejuvenation occurs is identified as the yield stress σ y of the gel. The minimum steady state shear rate ƴm obtained from creep experiments agrees well with the end of the plateau region in a controlled shear rate flow curve, indicating a shear localization below ƴm. A steady state shear banding in the plateau region of the flow curve observed in particle velocimetry measurements in a couette geometry confirms that the dilute suspensions of GO platelets form a thixotropic yield stress fluid (TYSF). In the second part, we report that the creep experiments on a nematic liquid crystalline suspension of Graphene Oxide platelets which was established recently as a TYSF exhibit two characteristic timescales Tc and Tf marking the onset of yielding, and a final steady state of flow respectively. We show that both Tc and Tf exhibit a power law dependence on the applied stress σ which can be linked to the steady state flow behaviour of a TYSF. The smooth transition from Andrade creep to the onset of flow with ƴ~ t 0.7 at a critical strain ƴc for different applied stresses, is well captured by the master curve for the creep compliance, obtained through a simple scaling of the creep times with either Tc or Tf . We propose that the absence of diverging timescales for onset of flow as σ→ yield stress σy from above, is a characteristic feature of TYSF. The thesis concludes with a summary of the main results and a brief account of the scope of future work described in Chapter 8.

This thesis describes the conductivity fluctuations or noise measurements in graphenebased field effect transistors. The main motivation was to study the effect of disorder on the electronic transport in graphene. In chapter 4, we report the noise measurements in graphene field effect (GraFET) transistors with varying layer numbers. We found that the density dependence of noise behaves oppositely for single and multilayer graphene. An analytical model has been proposed to understand the microscopic mechanism of noise in GraFETs, which reveals that noise is intimately connected to the band structure of graphene. Our results outline a simple portable method to separate the single layer devices from multi layered ones. Chapter 5 discusses the noise measurements in two systems with a bandgap: biased bilayer graphene and graphene nanoribbon. We show that noise is sensitive to the presence of a bandgap and becomes minimum when the bandgap is zero. At low temperature, mesoscopic graphene devices exhibit universal conductance fluctuations (UCF) arising due to quantum interference effect. In chapter 6, we have studied UCF in single layer graphene and show that it can be sensitive to the presence of various physical symmetries. We report that time reversal symmetry exists in graphene at low temperature and, for the first time, we observed enhanced UCF at lower carrier density where the scattering is dominated by the long-range Coulomb scattering. Chapter 7 presents the transport and noise measurements in single layer graphene in the quantum Hall regime. At ultra-low temperature several broken symmetry states appear in the lowest Landau level, which originate possibly due to strong electron-electron interactions. Our preliminary noise measurements in the quantum Hall regime reveal that the noise is sensitive to the bulk to edge transport and can be a powerful tool to investigate these new quantum states.

The growing incidences of orthopedic problems globally have created a huge demand for strong bioactive materials for bone tissue engineering. Over the years, studies have shown chemical, physical, and mechanical properties of biomaterials influence the cellular interactions at the material-tissue interface, which subsequently controls biological response to materials. Strong biomaterials with surface properties that actively direct cellular response hold the key for engineering the next generation orthopedic implants. With its unique properties graphene can be used to reinforce poly (ε-caprolactone) (PCL) to prepare strong and bioactive polymer nanocomposites for bone tissue regeneration. The thesis entitled ―Engineering bioactive and multifunctional graphene polymer composites for bone tissue regeneration” systematically studies the effect of different chemically functionalized and metal-graphene hybrid nanoparticles in PCL composites for bone tissue engineering. The thesis comprises of seven chapters. Chapter 1 is an outline review on the impact of graphene and graphene derived particles to prepare supporting substrates for tissue regeneration and the associated cell response to multifunctional graphene substrate. This chapter discusses how cells interact with different graphene based particles and the interplay between cells performance and multifunctional properties of graphene based substrates. Chapter 2 describes the role, if any, of the functionalization of graphene on mechanical properties, stem cell response and bacterial biofilm formation. PCL composites of graphene oxide (GO), reduced GO (RGO) and amine-functionalized GO (AGO) were prepared at different filler contents (1%, 3% and 5%). Although the addition of the nanoparticles to PCL markedly increased the storage modulus, this increase was higher for GO and AGO than with RGO. In vitro cell studies revealed that the AGO and GO particles significantly increased human mesenchymal stem cell (hMSC) proliferation. AGO was most effective in augmenting stem cell osteogenesis leading to mineralization. Bacterial studies revealed that interaction with functionalized GO induced bacterial cell death due to membrane damage which was further accentuated by amine groups in AGO. The synergistic effect of oxygen containing functional groups and amine groups on AGO-reinforced composites renders the optimal combination of improved modulus, favorable stem cell response and biofilm inhibition desired for orthopaedic applications. In Chapter 3, toward preparing strong multi-biofunctional materials, poly(ethylenimine) (PEI) conjugated graphene oxide (GO_PEI) was synthesized using poly(acrylic acid) (PAA) as spacer and incorporated in PCL at different fractions. GO_PEI significantly promoted proliferation and formation of focal adhesions in hMSCs on PCL. GO_PEI was highly potent in inducing stem cell osteogenesis leading to 90% increase in alkaline phosphatase activity and mineralization over neat PCL with 5% filler content and was 50% better than GO. Remarkably, 5% GO_PEI was as potent as soluble osteo-inductive factors. Increased adsorption of osteogenic factors due to the amine and oxygen containing functional groups on GO_PEI augment stem cell differentiation. GO_PEI was also highly efficient in imparting bactericidal activity with 85% reduction in counts of E. coli colonies compared to neat PCL at 5% filler content and was more than twice as efficient as GO. This may be attributed to the synergistic effect of the sharp edges of the particles along with the presence of the different chemical moieties. Thus, in contrast to using labile biomolecules, GO_PEI based polymer composites can be utilized to prepare bioactive resorbable biomaterials for fabricating orthopedic devices for fracture fixation and tissue engineering. Chapter 4 describes the preparation of hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and its advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) nanoparticles were synthesized by facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200 – 300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared incorporating RGO_Sr particles in PCL. The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare scaffolds with osteoinductive property. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration. Chapter 5 discusses the use of hybrid graphene-silver particles (RGO_Ag) to reinforce PCL and compared with PCL/RGO and PCL/Ag composites containing RGO and silver nanoparticles (AgNPs), respectively. RGO_Ag hybrid particles were well dispersed in the PCL matrix unlike the RGO and AgNPs due to enhanced exfoliation. RGO_Ag led to 77 % increase in the modulus of PCL and provided a conductive network for electron transfer. Electrical conductivity increased four orders of magnitude from 10-11 S/cm to 10-7 S/cm at 5 wt % filler that greatly exceeded the improvements with the use of RGO and AgNP in PCL. RGO_Ag particles reinforced in PCL showed sustained release of silver ions from the PCL matrix unlike the burst release from PCL/Ag. PCL/RGO_Ag and PCL/RGO composites were non-toxic to hMSCs and supported osteogenic differentiation unlike the PCL/Ag composites which were highly toxic at ≥3% filler content. The PCL/RGO_Ag composites exhibited good antibacterial effect due to a combination of silver ion release from the AgNPs and the mechanical rupture induced by the RGO in the hybrid nanoparticles. Thus, the synergistic effect of Ag and RGO in the PCL matrix uniquely yielded a multifunctional material for use in implantable biomedical devices and tissue engineering. Chapter 6 presents investigation of potential differences in the biological response to graphene in polymer composites in the form of 2D substrates and 3D scaffolds. Results showed that osteoblast response to graphene in polymer nanocomposites is markedly altered between 2D substrates and 3D scaffold due to the roughness induced by the sharp edges of graphene at the surface in 3D but not in 2D. Osteoblast organized into aggregates in 3D scaffolds in contrast to more well spread and randomly distributed cells on 2D discs due to the macro-porous architecture of the scaffolds. Increased cell-cell contact and altered cellular morphology led to significantly higher mineralization in 3D scaffolds compared to 2D. This study demonstrates that the cellular response to nanoparticles in composites can change markedly by varying the processing route. Chapter 7 summarizes the important results and future directions of the work. This chapter provides general conclusions arising from this study, and makes suggestions for future work designed to provide a greater understanding of the in vivo response in terms of bio-distribution of the released functionalized graphene from the scaffold or substrate must be assessed with special attention on their accumulation or excretion.

Forests have as a of late become increasingly plagued with bark beetle infestations as a result of climate change. The damage caused by tree killing bark beetles has within recent years seen a substantial increase. Detecting and removing infested trees at an early stage is an essential part of mitigating the spread of and the damage caused by the beetle. Today, the most common way of early detection is visual detection by forestry personnel. However, this is time consuming with highly variable results. In this thesis a novel approach to tracing the European spruce bark beetle through pheromone detection is investigated. With this approach, the antennae of the beetle were paired with an epitaxial graphene chip in order to create a bioinspired smell sensor. Tests were conducted on the sensor in order to investigate how the resistance changed over the chip as a result of the sensor being exposed to the pheromone 2-methyl-3-buten-2-ol. As a result of the tests, a corelation between exposing the sensor to pheromone and an increase of the resistance over the graphene chip was noted. However, more tests need to be conducted in order to draw any definite conclusions about the efficacy of the sensor in its current form. Additionally there are opportunities to investigate further optimization alternatives regarding the design of the sensor.

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Doctor of Philosophy / Department of Chemical Engineering / Vikas Berry / Graphene - a single atom thick two dimensional sheet of sp[superscript]2 bonded carbon atoms arranged in a honeycomb lattice - has shown great promise for both fundamental research & applications because of its unique electrical, optical, thermal, mechanical and chemical properties. Derivatization of graphene unlocks a plethora of novel properties unavailable to their pristine parent “graphene”. In this dissertation we have synthesized various structural and chemical derivatives of graphene; characterized them in detail; and leveraged their exotic properties for diverse applications. We have synthesized protein/DNA/ethylenediamine functionalized derivatives of graphene via a HATU catalyzed amide reaction of primary-amine-containing moieties with graphene oxide (GO) – an oxyfunctional graphene derivative. In contrast to non-specificity of graphene, this functionalization of GO has enabled highly specific interactions with analytes. Devices fabricated from the protein (concanavalin – A) and DNA functionalized graphene derivatives were demonstrated to enable label-free, specific detection of bacteria and DNA molecules, respectively, with single quanta sensitivity. Room temperature electrical characterization of the sensors showed a generation of ~ 1400 charge carriers for single bacterium attachment and an increase of 5.6 X 10[superscript]12 charge carriers / cm[superscript]2 for attachment of a single complementary strand of DNA. This work has shown for the first time the viability of graphene for bio-electronics and sensing at single quanta level. Taking the bio-interfacing of graphene to the next level, we demonstrate the instantaneous swaddling of a single live bacterium (Bacillus subtilis) with several hundred sq. micron (~ 600 µm[superscript]2) areal protein-functionalized graphene sheets. The atomic impermeability and high yield strength of graphene resulted in hermetic compartmentalization of bacteria. This enabled preservation of the dimensional and topological characteristics of the bacterium against the degrading effects of harsh environments such as the ultrahigh vacuum (~ 10[superscript]-5 Torr) and high intensity electron beam (~ 150 A/cm[superscript]2) in a transmission electron microscope (TEM) column. While an unwrapped bacterium shrank by ~ 76 % and displayed significant charge buildup in the TEM column; a wrapped bacterium remained uncontracted and undamaged owing to the graphenic wraps. This work has shown for the first time an impermeable graphenic encasement of bacteria and its application in high vacuum TEM imaging without using any lengthy traditional biological TEM sample preparation techniques. In an inch-scale, we fabricated robust free-standing paper composed of TWEEN/Graphene composite which exhibited excellent chemical stability and mechanical strength. This paper displayed excellent biocompatibility towards three mammalian cell lines while inhibiting the non-specific binding of bacteria (Bacillus cereus). We predict this composite and its derivatives to have excellent applications in biomedical engineering for transplant devices, invasive instrument coatings and implants. We also demonstrate a novel, ultra-fast and high yield process for reducing GO to reduced graphene oxide (RGO) using a facile hydride-based chemistry. The RGO sheets thus-produced exhibited high carrier mobilities (~ 100-600 cm[superscript]2/V•s) and reinstatement of the ambipolar characteristic of graphene. Raman spectra and UV-Vis spectroscopy on the RGO sheets displayed a high degree of restoration of the crystalline sp2 lattice with relatively low defects. We fabricated graphene nanoribbons (GNRs) – 1D structural derivatives of graphene – using a nano-scale cutting process from highly oriented pyrolytic graphite (HOPG) blocks, with widths pre-determinable between 5 nm to 600 nm. The as-produced GNRs had very high aspect ratio in the longitudinal direction (~ 0.01); exhibited predominantly mono-layered structure (< 10 % bilayer); and smooth edges (Raman I[subscript]D/G ~ 0.25 -0.28). Low temperature electrical transport measurements on back-gated thin film GNR devices were performed and a carrier mobility of ~ 20 ± 4 cm[superscript]2/V•s with sheet resistances of 2.2-5.1 MΩ / □ was extracted. Despite the ~ 50 nm thicknesses of the films, a clear bandgap scaling was observed with transport via variable range hopping (VRH) in 2 and 3 dimensions. This work demonstrates the first fully functional narrow pristine GNR thin-film field effect transistors (FETs). In addition we fabricated graphene quantum dots (GQDs) – 0D derivatives of graphene with dimensions < 100 nm – using a slight variation of our nano-scale cutting strategy, where the cleavage process is carried out in two dimensions. A high degree of control on the dimensions (Std. Dev. of ~ 5 nm for 50 X 50 nm square GQDs) and shape (pre-determinable between square, rectangle, triangle and trapezoid) of the as-synthesized GQDs is demonstrated. The optical properties of the GQDs such as the UV-Vis absorbance and photoluminescence were studied and their facile tunability was demonstrated depending on their dimensions. This work demonstrates for the first time the high throughput fabrication of GQDs with tunable dimensions and shape.