MSc in Analytical Chemistry: MAC 5514 - Nanotechnology (Vocabulary Flashcards)

Vocabulary flashcards covering key nanoscale concepts, materials, synthesis, and characterization from the lecture notes.

Nanotechnology

Understanding and control of matter at dimensions roughly 1–100 nanometers, where unique phenomena enable novel applications.

Nanoscale

The size range (1–100 nm) where materials exhibit unique physical, chemical, and biological properties.

National Nanotechnology Initiative (NNI)

US federal program (established 2000) coordinating nanotechnology research across agencies to promote R&D and applications.

Biomimicry in nanotechnology

Design approach inspired by natural patterns (e.g., lotus leaves, butterfly wings) to create nanoscale materials with special properties.

Quantum dot (QD)

A nanoscale semiconductor crystal (2–10 nm) with a size-dependent band gap that emits light when excited.

Band gap energy

Difference between valence and conduction bands in a semiconductor; in QDs it depends on size (smaller QD → larger gap).

Quantum confinement

Quantum-mechanical effect causing discrete energy levels when carriers are confined to nanoscale dimensions.

Blue shift

Emission moves to shorter wavelengths as particle size decreases.

Red shift

Emission moves to longer wavelengths as particle size increases.

Quantum yield (QY)

Ratio of photons emitted to photons absorbed by a fluorophore; higher QY means brighter emission.

Stokes shift

Difference between absorption and emission maxima; large shifts reduce spectral overlap (crosstalk).

Two-photon cross-section

Measure of two-photon absorption; larger cross-sections enable deeper tissue imaging with two-photon excitation.

Surface area to volume ratio (S/V)

Ratio that increases at the nanoscale, enhancing surface-driven activity for catalysis, drug delivery, etc.

Fullerenes (C60)

Molecular carbon cages (e.g., Buckminsterfullerene) consisting of 60 carbons arranged in a spherical structure; highly reactive and cycloaddable.

Buckminsterfullerene (C60)

The classic fullerene; a spherical C60 molecule with 12 pentagons and 20 hexagons resembling a soccer ball.

Cycloaddition with fullerenes

Reactions where fullerenes undergo [2+1], [3+2], [4+2] cycloadditions to form fullerene derivatives.

Carbon nanotubes (CNTs)

Cylindrical carbon allotropes (SWNTs and MWNTs) with high strength and electrical conductivity; properties depend on chirality.

Chirality in CNTs

The rolling angle of the graphene sheet (chiral vector) determining metallic vs semiconducting behavior.

CNT synthesis methods

Common CNT fabrication methods: chemical vapor deposition (CVD), laser ablation, and arc discharge.

Graphene

A single 2D layer of carbon atoms in a honeycomb lattice with exceptional electrical and mechanical properties.

CNT functionalization

Chemical modification of CNT surfaces (covalent or non-covalent) to improve solubility, biocompatibility, and targeting.

Surfactants in nanoparticle synthesis

Amphiphilic stabilizers (e.g., SDS, CTAB, oleic acid) that control size/shape and prevent aggregation.

Nucleation

Formation of the initial small particles (1–2 nm or smaller) during nanoparticle synthesis.

Growth

Increase in size of nuclei to form larger particles, controlled by temperature, time, solvents, and surfactants.

Ostwald ripening

Thermodynamic process where larger particles grow at the expense of smaller ones, lowering the system’s energy.

Turkevich method

Salt-reduction synthesis of gold nanoparticles using citrate as both reducer and capping agent to yield monodisperse spheres.

Electrochemical synthesis

Direct reduction of metal ions at an electrode under controlled potential, with stabilizers to prevent aggregation.

Photolithography

Top-down patterning using light to transfer masks onto photoresist, enabling sub-100 nm features.

Top-down fabrication

Approach that carves or patterns bulk materials into nanoscale structures (e.g., lithography).

Bottom-up fabrication

Approach building nanoscale structures from atoms/molecules via chemical synthesis.

Nucleation vs Growth interplay

Relationship determining final nanoparticle size distribution: rapid nucleation yields many small particles; slower growth yields larger particles.

Transmission Electron Microscopy (TEM)

Imaging technique that transmits electrons through thin samples to reveal morphology, crystallography, and composition with sub-nanometer resolution.

Scanning Electron Microscopy (SEM)

Imaging technique that scans a focused electron beam over a surface to reveal topography with ~1 nm resolution.

Atomic Force Microscopy (AFM)

Scanning probe technique using a sharp tip on a cantilever to map surface topography via cantilever deflection; can operate in air or liquid and even manipulate atoms.

Scanning Probe Microscopy (SPM)

Family of techniques (including STM and AFM) that map surfaces by scanning a probe near the sample.