Chapter Four · failure evidence
What Nanoparticle Synthesis & Doping got wrong, from 59 dissertations
The records document various synthesis and doping failures encountered during nanoparticle and nanomaterial fabrication. These issues span colloidal agglomeration, thermal degradation, structural phase segregation from overdoping, and processing incompatibilities in composite matrices. These records come from PhD theses at 23 institutions, 2021 to 2026. Each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.
Colloidal instability and uncontrolled nanoparticle aggregation degrade material structure and dispersion
Nanoparticles frequently aggregate out of suspension due to missing capping ligands, poor electrostatic stabilization, or improper solvent conditions. This uncontrolled agglomeration causes severe pore blocking, non-uniform film deposition, and mechanical instability across different substrates.
Tried and failed
increasing plasmonic nanoparticle loading in heterostructures applied to photoelectrochemical water splitting photoanodes. Outcome: worse than baseline. Reason: nanoparticle aggregation and optical coupling disrupted uniform shell coating, degrading overall photoelectrochemical performance
Considered and rejected
Considered and rejected: Rejected physical blending of nanoparticles directly into casting solutions because nanoparticle aggregation caused poor dispersion, pore defects, and entrapment within the polymer matrix.
Membrane Surface Functionalization Through Nanomaterials for Wastewater Treatment · oURspace
Considered and rejected
Considered and rejected: Rejected commercialized NiO paste and raw NiO nanopowders for mesoporous HTL because particle aggregation (up to 800 nm-1 µm) prevented uniform film coverage; replaced with synthesized 20 nm NiO nanoparticles
Fabrication and characterization of lead-free and lead based perovskite solar cells · Imperial
Considered and rejected
Considered and rejected: Rejected nanocomposites of TiO2/SiO2/CdS nanoparticles blended with polymers due to particle aggregation and high scattering/optical loss, choosing coordinated molecular hybrids instead.
Elucidating exciton-polaritons in organic and two-dimensional metal halide semiconductors · Georgia Tech
Tried and failed
EDC carbodiimide crosslinking of colloidal nanoparticles applied to surface conjugation to functionalized nanowires. Outcome: unstable. Reason: carboxylic acid-functionalized quantum dots aggregated out of solution during crosslinking
Design and Characterization of Hybrid Biological-Inorganic Systems · Harvard
Tried and failed
antisolvent precipitation using bad solvent for polymer shell applied to block copolymer templated nanocrystal synthesis. Reason: Insolubility of the polymer shell in the antisolvent caused precursor aggregation rather than colloidal nanoparticle formation
Continuous Production and Improved Stabilities of Luminescent Colloidal Perovskite Nanocrystals as Next-Generation Emitters · Georgia Tech
Tried and failed
nanocrystal synthesis without shape-directing ligand applied to supported bimetallic alloy nanoparticles. Outcome: unstable. Reason: absence of capping agent caused irregular particle morphology and severe agglomeration
Platinum-Based Nanocrystals and Their Use as Electrocatalysts toward Oxygen Reduction · Georgia Tech
Tried and failed
electrostatic adsorption of small highly charged peptides applied to layer-by-layer core-shell nanoparticles. Outcome: unstable. Reason: low layering ratios of small charged peptides induced particle bridging and aggregation
Tried and failed
drop casting nanoparticles for conformal coating applied to vertically aligned high-aspect-ratio nanotube arrays. Reason: nanoparticles aggregated at the tips instead of penetrating, blocking ion transport
Tried and failed
co-encapsulating oppositely charged nanoparticles applied to vesicle lumen compartmentalisation. Outcome: unstable. Reason: mutual electrostatic aggregation and charge neutralisation between the particle populations
Dynamic control of compartmentalisation in artificial cell models · Imperial
Considered and rejected
Considered and rejected: Rejected commercial Cu, Cu2O, and ZnO nanoparticles due to massive agglomeration and chemical instability during drying
Wpływ przepływu mikrofluidycznego oraz nanocząstek metalicznych na właściwości amyloidogenne ludzkiej cystatyny C The Influence of Microfluidic Flow and Metallic Nanoparticles on the Amyloidogenic Properties of Human Cystatin C · AMUR - Repozytorium Uniwersytetu im. Adama Mickiewicza w Poz
Considered and rejected
Considered and rejected: Rejected increasing T-mixer diameter beyond 0.02 inch to produce larger nanoparticles due to particle agglomeration.
Considered and rejected
Considered and rejected: Rejected direct carbonization of Ag@PDA without a SiO2 protective shell because nanoparticles sintered and agglomerated during thermal annealing at 700 °C.
Active sites on copper-based catalysts for electrochemical CO2 reduction selectively to C2+ products · EPFL
Tried and failed
high metal-oxide nanoparticle loading in carbon nanocomposite inks applied to printed microsupercapacitor electrodes. Outcome: worse than baseline. Reason: nanoparticle clustering severely degraded electrochemical capacitance compared to additive-free electrodes
Dopant incorporation introduces carrier traps, disrupts bonding networks, and impairs electronic properties
Chemical doping often generates deep midgap trap states that quench photoresponse and hinder catalytic charge transfer. Furthermore, foreign dopant atoms disrupt host crystal or polymer bonding networks, shifting chemical potentials and diminishing carrier mobility.
Tried and failed
nonmetal doping with phosphorus applied to semiconductor photocatalysts. Outcome: worse than baseline. Reason: deep midgap states acted as electron traps rather than facilitating catalytic charge transfer
Tried and failed
transition metal oxide high-concentration surface doping applied to semiconductor photoanodes for pollutant degradation. Outcome: worse than baseline. Reason: excessive loading lowered the valence band redox potential too much, reducing oxidation capacity
The Development of Energy Efficient Wastewater Treatment: Electrochemical Oxidation and PFACs liquid-liquid Extraction · Georgia Tech
Tried and failed
sol-gel Pechini transition metal co-doping applied to semiconductor photocatalysts. Outcome: no signal. Reason: insufficient suppression of high-valence dopant trap states that quench photoresponse
Lost to a baseline
Bi2Ti2O7 photocatalytic activity was degraded after doping/alloying with Fe3+ or Mn2+ compared to pristine SCS-synthesized Bi2Ti2O7
Considered and rejected
Considered and rejected: Rejected conventional dry etching or laser writing doping for P3CPT patterning due to severe degradation of polymer electronic properties.
Liquid gated organic devices for sensing applications: from transistors to single molecule break junctions · IRIS - POLITO - prod
Considered and rejected
Considered and rejected: Rejected chemical doping as the disorder-tuning method because it shifts the chemical potential and alters lattice constants/electronic structures.
Study of superconductivity in quantum materials using controlled disorder · Iowa State
Considered and rejected
Considered and rejected: Rejected direct substitutional doping of CNT lattice because it disrupts sp2 bonding, increases scattering, and reduces carrier mobility.
Lost to a baseline
CCD of unheated MOS PBM GSEs (0.1–0.3 mA·cm^-2) was inferior to pure sulfide PBM glass baseline (1.5 mA·cm^-2) due to oxygen doping suppressing reactive Si-S
Studies on mixed oxy-sulfide and mixed oxy-sulfide-nitride lithium glassy solid-state electrolytes · Iowa State
High processing temperatures trigger dopant loss, structural damage, and uncontrolled sintering
Thermal treatments cause volatile dopant precursors to sublime and drive unwanted crystal phase transformations. In addition, high-temperature calcination and sintering processes degrade nanoparticle structures, increase particle sizes beyond functional limits, or leave them arrested in irregular shapes.
Tried and failed
thermal diffusion doping applied to semiconductor photocatalyst preparation. Outcome: worse than baseline. Reason: induced complete rutile phase transformation and dopant evaporation during high-temperature processing
Tried and failed
transition metal doping with high-temperature calcination applied to photocatalytic nitrogen reduction. Outcome: worse than baseline. Reason: high-temperature calcination of metal dopants lowered photocatalytic activity compared to undoped material
Influence of Carbon and Oxygen for Photocatalytic Nitrogen Fixation on Titania · Georgia Tech
Tried and failed
High-temperature chemical anion doping applied to oxide nanoparticle electrocatalysts. Outcome: worse than baseline. Reason: Severe structural degradation of nanoparticles led to reduced oxygen evolution reaction activity
Polymer-Ligated Nanocrystals with Tunable Dimensions, Compositions, and Architectures · Georgia Tech
Tried and failed
direct thermal synthesis doping with volatile precursors applied to high-temperature ceramic semiconductor synthesis. Outcome: no signal. Reason: dopant precursors sublimed below the synthesis temperature required for host lattice formation
Tried and failed
electron beam-induced coalescence applied to large metallic nanoparticles. Outcome: did not converge. Reason: larger nanoparticles become arrested in metastable non-spherical shapes due to insufficient energy for complete sintering
In situ TEM investigation on the beam-driven mechanisms of Ag/Au nanoparticles at room temperature · Imperial
Tried and failed
in situ metal nanoparticle sintering on 2D substrates applied to conductive polymer nanocomposite curing. Reason: Nanoparticle agglomeration increased particle size and melting temperature above the matrix curing threshold
High Thermal Conductivity Epoxy Composites In The Application Of 3D Semiconductor Packaging · Georgia Tech
Tried and failed
thermal, plasma, and electrical sintering applied to patterned nanoparticle structures in collapsed hydrogels. Reason: failed to produce well-preserved, evenly sintered conductive silver structures
Implosion Fabrication: Rethinking 3D Nanofabrication from First Principles · MIT
Considered and rejected
Considered and rejected: Rejected vapor deposition for doping due to large boiling point differences between ThF4 and CaF2 causing high dopant loss
The nuclear excitation of Thorium-229 in the CaF2 environment : Development of a crystalline nuclear clock Anregung des Thorium-229 Kerns in einer Kalziumfluorid-Matrix · DSpace-CRIS at TU Wien
Excessive dopant concentrations exceed solubility limits and induce phase segregation
Introducing dopants beyond their thermodynamic solubility limits causes phase separation and the formation of secondary resistive impurities. Overdoping disrupts the parent crystal lattice and lamellar structures, leading to severe capacity loss and degraded performance.
Tried and failed
high-concentration substitutional cation doping applied to perovskite metal oxide nanoparticles. Reason: Dopant concentration exceeded solubility limits, forming secondary impurity phases rather than single-phase perovskite.
Tried and failed
doping oxide and phosphate impurity phases applied to catalytic nitrate reduction. Outcome: worse than baseline. Reason: impurity phases decreased hydrogenation activity instead of acting as cocatalysts
Removal of nitrate with nanoscale nickel phosphides · Iowa State
Tried and failed
high-concentration isovalent cation co-doping applied to oxide proton conductors. Outcome: worse than baseline. Reason: exceeded solubility limit causing segregation of a resistive secondary phase
Investigation of structure and conductivity of LaNb0.9Mo0.1O4.05 based materials · Imperial
Considered and rejected
Considered and rejected: Single-element Mn doping for ultrahigh-Ni (>90% Ni) stabilization when operated under energy-density control, because it induces premature H2–H3 phase transition and severe interphasial degradation.
High-voltage oxide cathodes for high-energy-density lithium-ion batteries · UT Austin
Tried and failed
high-concentration chemical doping applied to conjugated polymer thermoelectric materials. Outcome: worse than baseline. Reason: severe structural disruption of lamellae caused over-doping, decreasing Seebeck coefficient without increasing electrical conductivity
Examining thermal and charge transport in organic materials with pi-electron interactions · Georgia Tech
Tried and failed
increasing precursor molar ratio in alloy synthesis applied to bimetallic nanoparticle preparation. Reason: excess iron precursor caused phase separation into biphasic core-shell nanoparticles with surface iron oxide
Responsive dual nanoparticle ¹⁹F magnetic resonance molecular imaging probes · UT Austin
Tried and failed
high-concentration multi-element substitutional doping applied to high-nickel oxide cathode materials. Outcome: worse than baseline. Reason: excess dopants cause severe capacity loss and synthesis phase inhomogeneity
High-voltage oxide cathodes for high-energy-density lithium-ion batteries · UT Austin
Nanoparticle incorporation into polymers causes optical scattering, curing inhibition, and processing defects
Blending nanoparticles into liquid monomers or polymer resins induces optical scattering, high viscosity, and incomplete matrix incorporation. These additives also inhibit standard curing reactions, leach out in reactive media, or obstruct the porosity of host frameworks.
Tried and failed
nanoparticle loading on porous polymer frameworks applied to conjugated microporous polymers for photocatalysis. Outcome: worse than baseline. Reason: nanoparticles obstructed the framework pores, significantly reducing the specific surface area
Considered and rejected
Considered and rejected: Rejected direct incorporation of conductive nanoparticles into photopolymer resin due to laser scattering, unwanted polymerization, poor mechanical properties, and low conductivity.
Development of 3D printed enzymatic biofuel cells for powering implantable biomedical devices · University of Nottingham Repository
Considered and rejected
Considered and rejected: Rejected UV photopolymerization for hybrid inorganic-organic ionogels due to nanoparticle light-scattering and photon shielding, adopting thermal polymerization instead.
Hybrid Ionogels and Self-Healing Electrolytes: Innovative Solutions for Safer Lithium Metal Batteries · IRIS - POLITO - prod
Considered and rejected
Considered and rejected: Rejected Ecoflex doped with 150 nm nanoparticles because smaller particle size inhibited curing of the polymer.
Improving Respiratory Sound Monitoring and Analysis through Noise Control, Sensor Design, and Real-World Considerations · JScholarship
Considered and rejected
Considered and rejected: Rejected silver and gold nanoparticle-loaded conductive hydrogels due to particle oxidation/cytotoxicity (Ag) and precursor viscosity/lack of percolation conductivity (Au).
Development of an injectable hydrogel electrode for the treatment of ventricular arrhythmias · UT Austin
Tried and failed
high-volume-fraction nanoparticle loading in liquid monomer applied to particle-reinforced elastomer synthesis. Reason: nanoparticles fail to incorporate completely into the liquid monomer above a critical volume fraction
Fracture of Heterogeneous Soft Materials · Harvard
Tried and failed
noble metal nanoparticle incorporation for electrical conductivity applied to injectable hydrogels. Outcome: unstable. Reason: Nanoparticles oxidized, leached in aqueous persulfate systems, failed below percolation threshold, and increased precursor viscosity excessively
Development of an injectable hydrogel electrode for the treatment of ventricular arrhythmias · UT Austin
Inappropriate reaction conditions prevent homogeneous doping and complete precursor conversion
Syntheses performed below required melt temperatures or without appropriate swelling solvents fail to facilitate homogeneous dopant infiltration into host structures. Sub-optimal precursor concentrations and lack of templating environments also lead to low product yields and unreacted starting phases.
Tried and failed
melt synthesis doping below liquidus temperature applied to solid-state electrolyte halide mixtures. Reason: reactants failed to form a molten homogeneous solution at target temperature, leading to incomplete doping
Borohydride-based solid electrolytes and polymer composite separators for lithium-ion batteries · Georgia Tech
Tried and failed
solution-based electrical doping without swelling solvent applied to conjugated polymer solar cell films. Outcome: worse than baseline. Reason: lack of swelling solvent prevented effective dopant penetration into the conjugated polymer layer
Application of solution-based electrical doping to non-fullerene organic solar cells · Georgia Tech
Tried and failed
low-temperature solid-state metathesis synthesis applied to chromium nitride nanoparticle synthesis. Reason: incomplete reaction yielding mixed nitride phases, unreacted oxide precursor, or reduced elemental metal
SYNTHESIS, CHARACTERIZATION, AND PHOTOTHERMAL PROPERTIES OF PLASMONIC METAL NITRIDE NANOPARTICLES · DalSpace
Tried and failed
sacrificial metal template pyrolysis with low dilution applied to single-atom catalyst synthesis. Reason: insufficient spatial isolation by the sacrificial metal allowed target metal atoms to aggregate into nanoparticles
MOF-Derived Electrocatalysts for Sustainable Energy Conversion/Storage Systems · Cornell
Considered and rejected
Considered and rejected: Rejected low reagent concentrations for hydrothermal SrF2 synthesis because they resulted in insufficient product yields despite yielding smaller nanoparticles
Synteza i zbadanie zjawiska up-konwersji nanocząstek sensybilizowanych jonami Er3+ i Ho3+ Synthesis and investigation of the up-conversion phenomenon in nanoparticles sensitized by Er3+ and Ho3+ ions · AMUR - Repozytorium Uniwersytetu im. Adama Mickiewicza w Poz
Considered and rejected
Considered and rejected: Rejected heating low-melting solids/high-boiling liquids for vapor doping due to condensing/overdoping and atmospheric reactions.
INELASTIC ELECTRON TUNNELLING SPECTROSCOPY (lETS) OF SILANE COUPLING AGENTS · De Montfort Open Research Archive (DORA)
Considered and rejected
Considered and rejected: Rejected solution polymerisation in homogeneous organic solvents (DMF, DMSO, MeCN) due to lack of templating conditions required for nanoparticle formation
Core-shell synthesis methods suffer from separate nucleation and non-conformal island deposition
Shell growth on nanoparticle seeds often fails when secondary homogeneous nucleation creates isolated particle populations instead of coated architectures. Poor seed adhesion and island growth on irregular geometries yield uneven coatings and aggregates rather than uniform core-shell morphologies.
Tried and failed
carbide nanoparticle core-shell deposition applied to noble metal electrocatalyst synthesis. Reason: Inconsistent core particle size distributions caused incomplete shell coverage and unattached metal nanoparticle precipitation.
Tried and failed
silica shell encapsulation applied to branched anisotropic nanoparticles. Outcome: unstable. Reason: produced irregular aggregates rather than forming a uniform conformal coating
All that glitters is gold: gold nanostars for enhanced fluroescence in the near infra-red window · Imperial
Tried and failed
heterogeneous core-shell nanoparticle growth applied to magnetic-upconversion nanocomposite synthesis. Reason: nucleation yielded separate homogeneous particle populations instead of heterogeneous core-shell coating
Phosphonate-anchored ligands for upconversion imaging nanoprobes · Imperial
Tried and failed
direct seed-mediated metal shell overgrowth applied to bimetallic core-shell nanoparticle synthesis. Outcome: unstable. Reason: uncontrolled island-like deposition caused poor colloidal stability and nanoparticle aggregation
Peroxidase-mimicking nanomaterials for amplified lateral flow immunoassays · Imperial
Tried and failed
nanoparticle seed grafting on unfunctionalized surfaces applied to silica core-shell nanoparticle synthesis. Reason: poor seed adhesion caused formation of unwanted nanowire networks instead of uniform shells
All that glitters is gold: gold nanostars for enhanced fluroescence in the near infra-red window · Imperial
Left open by the authors
Problems the authors named and did not get to.
Left open
Synthesize ternary nanocomposites by crosslinking nanoparticles or using core/shell architectures to improve upconversion nanoparticle emission utilization efficiency. Blocker: Requires a wet chemistry and nanomaterials laboratory to synthesize polymer-ligated nanocrystals and characterize optical properties.
Polymer-Ligated Nanocrystals with Tunable Dimensions, Compositions, and Architectures · Georgia Tech
Left open
Resolve phase separation and purification issues encountered during grafting-to phosphonate coupling onto silica nanoparticles. Blocker: Requires a wet-lab chemistry setup for nanoparticle synthesis, chemical coupling, and purification
Left open
Dope conjugated microporous polymers with heteroatoms and functionalize their surfaces with functional groups or metal nanoparticle cocatalysts for photocatalysis. Blocker: Requires a wet chemistry synthesis lab, specialized precursors, and physical characterization equipment.
Left open
Isolate and clarify the individual photocatalytic roles of nitrogen/ammonium precursors versus nickel doping in sol-gel synthesized TiO2 for hydrogen production. Blocker: Requires a wet chemistry laboratory, sol-gel synthesis equipment, and photoreaction apparatus.
Producción de hidrógeno mediante fotocatálisis heterogénea · accedaCRIS
Left open
Investigate co-doping strategies in spray-pyrolysis-deposited iron oxide thin films to enhance photocatalytic activity. Blocker: Requires a wet chemistry and material synthesis lab with spray pyrolysis apparatus to synthesize and test thin films.
Elaboration and optimization of Iron Oxide thin films deposited via spray pyrolysis. Applications in water treatment · DSpace at University of El Oued
Left open
Test alternative stabilizing agents or dopants during silver nanoparticle synthesis to evaluate changes in porosity, biocompatibility, and catalytic selectivity. Blocker: Requires a wet chemistry lab and materials characterization equipment to synthesize and test nanoparticles.
Exploring the Mechanisms of the Early Stages of the Formation of Silver Nanoparticles and the Role of Organic Additives · Leibniz Universität Hannover Repository
Left open
Control the graded refractive index profile shapes (linear, sub-linear, super-linear) via nanoparticle synthesis and deposition to improve anti-reflective performance. Blocker: Requires chemical synthesis (mesoporous silica nanoparticles) and wet-lab fabrication/deposition equipment.
Left open
Map the 3D arrangement of sintered nanoparticles using tomographic reconstruction and evaluate catalytic performance across particle size ratios. Blocker: Requires synthesized nanoparticle samples and physical experimental apparatus (electron tomography, catalytic testing)
Kinetic Manipulation of Self-Assembling Systems for Scalable Nanomaterials Synthesis · MIT
Left open
Investigate thermal shielding methods to prevent CdTe nanoparticle agglomeration and luminescence loss under high-temperature conditions in photovoltaic applications. Blocker: Requires a wet-chemistry synthesis and materials characterization lab to prepare, shield, and test CdTe nanoparticle coatings.
The influences of post-preparative treatments on luminescence from CdTe nanoparticles · Cranfield
Left open
Synthesize and measure low-doping R1-xR'xNiO3 series to determine the critical tolerance factor tc for metal-insulator transitions. Blocker: Requires chemical synthesis (sol-gel) and high-pressure oxygen annealing laboratory equipment
Metal-insulator transition in yttrium- and neodymium-doped lanthanum nickelates · UT Austin
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