Prabakaran Shankar is a materials researcher, builder, and entrepreneur exploring functional materials, nanostructures, sensors, and practical digital systems.https://prabakaranshankar.com/https://prabakaranshankar.com/blog/a-practical-system-for-organizing-research-notes-in-academia/https://prabakaranshankar.com/blog/a-practical-system-for-organizing-research-notes-in-academia/How I keep literature, research ideas, experiments, meetings, references, observations, and unfinished questions connected without turning note-taking into another full-time job.Thu, 20 Aug 2026 00:00:00 GMThttps://prabakaranshankar.com/stories/an-anisotropy-of-isotropy/https://prabakaranshankar.com/stories/an-anisotropy-of-isotropy/A sputtered zinc oxide film was expected to be uniform. Its unexpected colors revealed hidden differences in structure, composition, electrical behavior, and gas-sensing performance across a single glass slide.Wed, 12 Aug 2026 00:00:00 GMThttps://prabakaranshankar.com/blog/sync-obsidian-safely-onedrive-google-drive/https://prabakaranshankar.com/blog/sync-obsidian-safely-onedrive-google-drive/A practical guide to syncing an Obsidian vault with OneDrive or Google Drive instead of Obsidian Sync — setup steps, the official limitations, and how to avoid conflicts and data loss.Tue, 11 Aug 2026 00:00:00 GMThttps://prabakaranshankar.com/blog/obsidian-for-research-projects/https://prabakaranshankar.com/blog/obsidian-for-research-projects/A practical Obsidian workflow for researchers to organize projects, experiments, literature, meetings and ideas with linked notes and automatic templates.Mon, 10 Aug 2026 00:00:00 GMThttps://prabakaranshankar.com/blog/from-scattered-notes-to-a-trusted-knowledge-base/https://prabakaranshankar.com/blog/from-scattered-notes-to-a-trusted-knowledge-base/A capture, link, and review system that turns raw research notes into a linked knowledge base you can trace every claim back to.Sat, 08 Aug 2026 00:00:00 GMThttps://prabakaranshankar.com/publications/pebax-cnt-piezoresistive-sensors/https://prabakaranshankar.com/publications/pebax-cnt-piezoresistive-sensors/A bio-derived Pebax polymer loaded with just 0.4 wt% carbon nanotubes becomes a sustainable, multi-stage piezoresistive strain sensor that stays stable over 1,000 stretch-release cycles.Thu, 01 Jan 2026 00:00:00 GMThttps://prabakaranshankar.com/publications/pnipam-pegda-hydrogel-modeling/https://prabakaranshankar.com/publications/pnipam-pegda-hydrogel-modeling/A Design-of-Experiments study of 3D-printed PNIPAm-PEGDA hydrogels links monomer ratio to a 50-fold range in mechanical strength and a predictive model for tuning stiffness, swelling, and drug release.Thu, 01 Jan 2026 00:00:00 GMThttps://prabakaranshankar.com/publications/v2o5-go-glucose-sensing/https://prabakaranshankar.com/publications/v2o5-go-glucose-sensing/A V2O5-graphene oxide hybrid made by electrochemical exfoliation offers a lower-cost, non-noble-metal alternative for direct glucose electrooxidation and sensing.Mon, 01 Jan 2024 00:00:00 GMThttps://prabakaranshankar.com/publications/boron-zno-ammonia-sensing/https://prabakaranshankar.com/publications/boron-zno-ammonia-sensing/Optimized spray pyrolysis conditions grow c-axis oriented boron-doped ZnO films instead of the usual crystallinity loss, with 10 mol% boron giving the strongest, most selective room-temperature ammonia response.Sat, 01 Jan 2022 00:00:00 GMThttps://prabakaranshankar.com/publications/zn-polymer-nanosheets-biomedical-applications/https://prabakaranshankar.com/publications/zn-polymer-nanosheets-biomedical-applications/Zn-loaded PLLA nanosheets release therapeutic zinc ions steadily over 10-12 hours and show antibacterial activity against E. coli, supporting their use as wound-healing patches.Sat, 01 Jan 2022 00:00:00 GMThttps://prabakaranshankar.com/publications/electrocoagulation-micropollutant-removal/https://prabakaranshankar.com/publications/electrocoagulation-micropollutant-removal/Applied current and electrolyte counter-ion control the crystal phase and shape of iron electrocoagulation coagulants, with carbonate and bicarbonate electrolytes removing over 90% of pharmaceutical micropollutants.Wed, 01 Jan 2020 00:00:00 GMThttps://prabakaranshankar.com/publications/zno-graphene-oxide-core-shell/https://prabakaranshankar.com/publications/zno-graphene-oxide-core-shell/A one-pot, chemical-free laser-ablation route sequentially builds ZnO@graphene-oxide core-shell nanoparticles in water, with longer graphite ablation producing thicker GO shells.Wed, 01 Jan 2020 00:00:00 GMThttps://prabakaranshankar.com/publications/molecular-level-interactions-between-engineered-materials-and-cells/https://prabakaranshankar.com/publications/molecular-level-interactions-between-engineered-materials-and-cells/A review traces how cells sense a material's stiffness, morphology, and chemistry, following that signal from the cell surface through nuclear mechanotransduction to changes in gene expression.Sun, 25 Aug 2019 00:00:00 GMThttps://prabakaranshankar.com/publications/nanoparticle-interactions-hydrogels/https://prabakaranshankar.com/publications/nanoparticle-interactions-hydrogels/A gold nanoparticle's surface charge, more than its size, governs whether it aggregates inside a hydrogel: negatively charged particles aggregate while positively charged ones stay dispersed.Tue, 01 Jan 2019 00:00:00 GMThttps://prabakaranshankar.com/publications/recent-advances-in-2d-inorganic-nanomaterials-for-sers-sensing/https://prabakaranshankar.com/publications/recent-advances-in-2d-inorganic-nanomaterials-for-sers-sensing/A review of 2D inorganic SERS substrates, including graphene, boron nitride, metal oxides, and transition metal chalcogenides, surveys their enhancement mechanisms and the path toward portable SERS sensors.Tue, 01 Jan 2019 00:00:00 GMThttps://prabakaranshankar.com/publications/ultrasonic-cnt-ammonia-sensing/https://prabakaranshankar.com/publications/ultrasonic-cnt-ammonia-sensing/Ultrasonically treated, annealed carbon-nanotube networks show a striking dual response to ammonia: resistance rises with concentration, then drops three orders of magnitude above 2500 ppm.Tue, 01 Jan 2019 00:00:00 GMThttps://prabakaranshankar.com/publications/fluorine-doped-zno-thin-film-as-acetaldehyde-sensor/https://prabakaranshankar.com/publications/fluorine-doped-zno-thin-film-as-acetaldehyde-sensor/Fluorine doping shrinks ZnO crystallite size and increases micro-strain, and a 4 wt% fluorine-doped film gives the strongest, most selective room-temperature acetaldehyde response.Mon, 01 Jan 2018 00:00:00 GMThttps://prabakaranshankar.com/publications/hmt-zno-growth-and-sensing/https://prabakaranshankar.com/publications/hmt-zno-growth-and-sensing/HMTA plays a dual capping role in ZnO growth, steering crystal shape between nanoprisms and nanodisks, with the nanoparticle-decorated nanoprisms giving the best acetaldehyde selectivity.Mon, 01 Jan 2018 00:00:00 GMThttps://prabakaranshankar.com/publications/nano-ceria-as-xylene-sensor-role-of-cerium-precursor/https://prabakaranshankar.com/publications/nano-ceria-as-xylene-sensor-role-of-cerium-precursor/Precursor chemistry alone tunes spray-pyrolysis CeO2 sensing performance: the acetate-derived film forms nanosheets and gives the fastest, strongest room-temperature xylene response.Mon, 01 Jan 2018 00:00:00 GMThttps://prabakaranshankar.com/publications/pani-cdo-methanol-sensor/https://prabakaranshankar.com/publications/pani-cdo-methanol-sensor/A PANI-CdO nanocomposite with 10 wt% CdO outperforms the authors' earlier PANI-only sensor, reaching a room-temperature methanol response of 1580 with fast recovery.Mon, 01 Jan 2018 00:00:00 GMThttps://prabakaranshankar.com/publications/thermal-energy-v2o5-nanostructures/https://prabakaranshankar.com/publications/thermal-energy-v2o5-nanostructures/Hydrothermal, solution-combustion, and microwave heating each shape V2O5 into a distinct nanostructure, with the solution-combustion nanoflowers giving the most selective ethanol response.Mon, 01 Jan 2018 00:00:00 GMThttps://prabakaranshankar.com/publications/v2o5-nanofiber-xylene-sensor/https://prabakaranshankar.com/publications/v2o5-nanofiber-xylene-sensor/Higher precursor concentration turns spray-pyrolysis V2O5 into interconnected, flower-like nanofibers that give the strongest, most selective room-temperature xylene response among eight tested vapors.Mon, 01 Jan 2018 00:00:00 GMThttps://prabakaranshankar.com/publications/zno-pva-hydrogen-peroxide-biosensor/https://prabakaranshankar.com/publications/zno-pva-hydrogen-peroxide-biosensor/An Au/ZnO-PVA/CAT/Chitosan biosensor detects hydrogen peroxide with a 9.13 nanomolar detection limit and under 1-second response time, validated directly in human blood serum.Mon, 01 Jan 2018 00:00:00 GMThttps://prabakaranshankar.com/publications/electrospun-zno-nanorod-ethanol-sensor/https://prabakaranshankar.com/publications/electrospun-zno-nanorod-ethanol-sensor/A single-step electrospinning route grows ZnO nanorods with three distinct tip shapes, and the flat-ended, loosely packed nanorods give the strongest room-temperature ethanol response.Sun, 01 Jan 2017 00:00:00 GMThttps://prabakaranshankar.com/publications/laser-ablated-zno-ethanol-sensor/https://prabakaranshankar.com/publications/laser-ablated-zno-ethanol-sensor/ZnO nanospheres and nanorods made by chemical-free laser ablation in water both show clear room-temperature selectivity for ethanol, detectable down to 50 ppm.Sun, 01 Jan 2017 00:00:00 GMThttps://prabakaranshankar.com/publications/nanostructures-prepared-via-laser-ablation-of-tin-in-water/https://prabakaranshankar.com/publications/nanostructures-prepared-via-laser-ablation-of-tin-in-water/Laser pulse duration controls the size and oxide-shell chemistry of tin nanoparticles made by ablating a tin target in water, with the resulting core-shell particles able to sense ethanol vapor.Sun, 01 Jan 2017 00:00:00 GMThttps://prabakaranshankar.com/publications/pani-zno-methanol-sensor/https://prabakaranshankar.com/publications/pani-zno-methanol-sensor/A PANI-ZnO nanocomposite thin film with 20 wt% ZnO gives the strongest, most selective room-temperature methanol response among several tested loadings, responding in just 7 seconds.Sun, 01 Jan 2017 00:00:00 GMThttps://prabakaranshankar.com/publications/tio2-mn3o4-fruit-glucose-sensing/https://prabakaranshankar.com/publications/tio2-mn3o4-fruit-glucose-sensing/A TiO2-Mn3O4 hybrid electrode detects glucose without any enzyme, reaching a 0.01 micromolar detection limit and successfully measuring glucose directly in fruit samples.Sun, 01 Jan 2017 00:00:00 GMThttps://prabakaranshankar.com/publications/zno-nanobush-nanowire-ethanol-sensing/https://prabakaranshankar.com/publications/zno-nanobush-nanowire-ethanol-sensing/A template-free electrospinning route self-assembles ZnO into nanospheres, nanobushes, or pearl-chain nanowires, with the nanowire form reaching a room-temperature ethanol response of 78 at 100 ppm.Sun, 01 Jan 2017 00:00:00 GMThttps://prabakaranshankar.com/publications/cobalt-doped-zno-selectivity/https://prabakaranshankar.com/publications/cobalt-doped-zno-selectivity/Cobalt doping shifts a spray-pyrolysis ZnO film's gas selectivity between acetaldehyde and ethanol depending on doping level, without changing its 19-25 nm crystallite size range.Fri, 01 Jan 2016 00:00:00 GMThttps://prabakaranshankar.com/publications/magnesium-doped-zno-ammonia-sensing/https://prabakaranshankar.com/publications/magnesium-doped-zno-ammonia-sensing/Magnesium doping tunes spray-pyrolysis ZnO crystallite size and band gap, with the lowest-doping film reaching a room-temperature ammonia response of 796 at 100 ppm.Fri, 01 Jan 2016 00:00:00 GMThttps://prabakaranshankar.com/publications/nanostructured-cerium-doped-zno-thin-film-a-breath-sensor/https://prabakaranshankar.com/publications/nanostructured-cerium-doped-zno-thin-film-a-breath-sensor/Cerium-doped ZnO thin films sense acetone and ethanolamine, breath biomarkers for diabetes and liver disorders, with dopant concentration tuned separately for each target.Fri, 01 Jan 2016 00:00:00 GMThttps://prabakaranshankar.com/publications/substrate-temperature-zno-sensing/https://prabakaranshankar.com/publications/substrate-temperature-zno-sensing/Raising the spray-pyrolysis substrate temperature shifts ZnO grain shape from spherical to pebble-like and strengthens the room-temperature ammonia response, peaking at 623 K.Fri, 01 Jan 2016 00:00:00 GMThttps://prabakaranshankar.com/publications/zno-racetrack-anisotropic-sensing/https://prabakaranshankar.com/publications/zno-racetrack-anisotropic-sensing/A single sputter-deposited ZnO film shows the 'racetrack effect' creates a real spatial gradient in crystallite size, carrier mobility, and gas-sensing response across one nominally uniform substrate.Fri, 01 Jan 2016 00:00:00 GMThttps://prabakaranshankar.com/publications/copper-oxide-thin-film-temperatures/https://prabakaranshankar.com/publications/copper-oxide-thin-film-temperatures/Substrate temperature and annealing steer spray-pyrolysis copper oxide films toward the tenorite (CuO) phase over cuprite (Cu2O), with 623 K giving the best crystallinity.Thu, 01 Jan 2015 00:00:00 GMThttps://prabakaranshankar.com/publications/electronic-noses-for-food-quality-a-review/https://prabakaranshankar.com/publications/electronic-noses-for-food-quality-a-review/A review of electronic-nose research across milk, wine, tea, coffee, fish, and meat quality monitoring finds shared sensor hardware and algorithms, with sensor drift and cost the main barriers to industrial adoption.Thu, 01 Jan 2015 00:00:00 GMThttps://prabakaranshankar.com/publications/electrospun-tailored-zno-nanostructures-role-of-chloride-ions/https://prabakaranshankar.com/publications/electrospun-tailored-zno-nanostructures-role-of-chloride-ions/Adding chloride ions to an electrospinning precursor steers ZnO growth from nanospheres to pencil-like nanorods, and the nanorod morphology gives the strongest room-temperature ethanol response.Thu, 01 Jan 2015 00:00:00 GMThttps://prabakaranshankar.com/publications/manganese-doped-zno-gas-sensing/https://prabakaranshankar.com/publications/manganese-doped-zno-gas-sensing/Manganese doping shrinks ZnO crystallite size from 28 to 7 nm while keeping films selective to ammonia, with the best-performing film giving roughly 5x the undoped response and 60-day stability.Thu, 01 Jan 2015 00:00:00 GMThttps://prabakaranshankar.com/publications/metal-oxide-gas-sensing-mechanisms/https://prabakaranshankar.com/publications/metal-oxide-gas-sensing-mechanisms/A review of the redox chemistry behind metal-oxide gas sensing compares n-type (ZnO, SnO2, In2O3, WO3) and p-type (CuO, NiO) oxides across humidity, grain size, and dopant effects on sensitivity.Thu, 01 Jan 2015 00:00:00 GMThttps://prabakaranshankar.com/publications/zno-thickness-dependent-sensing/https://prabakaranshankar.com/publications/zno-thickness-dependent-sensing/Substrate temperature controls ZnO film thickness and grain size in this zinc-nitrate-precursor study, with the thinnest, highest-resistance film giving the strongest acetaldehyde response.Thu, 01 Jan 2015 00:00:00 GMThttps://prabakaranshankar.com/publications/a-simple-and-novel-room-temperature-ethanolamine-zno-nanosensor/https://prabakaranshankar.com/publications/a-simple-and-novel-room-temperature-ethanolamine-zno-nanosensor/Spray-pyrolysis ZnO films made with different water-ethanol precursor solvents show the ethanol-only film selectively detects ethanolamine at room temperature, with a stable response over 30 days.Wed, 01 Jan 2014 00:00:00 GMThttps://prabakaranshankar.com/publications/manganese-doped-sol-gel-zno-films/https://prabakaranshankar.com/publications/manganese-doped-sol-gel-zno-films/Pure and manganese-doped ZnO thin films are synthesized by sol-gel dip coating to characterize how manganese doping affects their structure and properties.Wed, 01 Jan 2014 00:00:00 GMThttps://prabakaranshankar.com/publications/nickel-doped-zno-ethanol-sensing/https://prabakaranshankar.com/publications/nickel-doped-zno-ethanol-sensing/Nickel doping narrows the optical band gap of spray-deposited ZnO thin films, and a 0.008 M nickel-doped film gives the strongest room-temperature ethanol response, responding in about 50 seconds.Wed, 01 Jan 2014 00:00:00 GMThttps://prabakaranshankar.com/publications/precursor-volume-zno-thin-films/https://prabakaranshankar.com/publications/precursor-volume-zno-thin-films/Increasing the spray-pyrolysis precursor volume from 15 to 45 mL thickens ZnO films from 225 to 781 nm and raises conductivity, with the thicker film's open structure favoring gas sensing.Wed, 01 Jan 2014 00:00:00 GMThttps://prabakaranshankar.com/publications/sol-gel-dip-coated-pure-and-fe-doped-nanostructured-zno-thin-films/https://prabakaranshankar.com/publications/sol-gel-dip-coated-pure-and-fe-doped-nanostructured-zno-thin-films/Pure and iron-doped ZnO thin films are grown by sol-gel dip coating, a low-temperature alternative to spray pyrolysis, to study how iron doping shapes the resulting nanostructure.Wed, 01 Jan 2014 00:00:00 GMThttps://prabakaranshankar.com/publications/solvent-volume-driven-zno-nanopetals-thin-films-spray-pyrolysis/https://prabakaranshankar.com/publications/solvent-volume-driven-zno-nanopetals-thin-films-spray-pyrolysis/Precursor volume alone steers spray-pyrolysis ZnO toward either better conductivity or better gas sensing, with a distinctive nanopetal morphology forming at 30 mL.Wed, 01 Jan 2014 00:00:00 GMThttps://prabakaranshankar.com/publications/volatile-organic-compounds-sensing-performance-of-zno-thick-film/https://prabakaranshankar.com/publications/volatile-organic-compounds-sensing-performance-of-zno-thick-film/A thick ZnO film is evaluated for its room-temperature sensing performance across a range of volatile organic compounds.Wed, 01 Jan 2014 00:00:00 GMThttps://prabakaranshankar.com/publications/zno-nanopebble-ammonia-sensor/https://prabakaranshankar.com/publications/zno-nanopebble-ammonia-sensor/A nanopebble-textured ZnO film made by high-temperature spray pyrolysis selectively senses ammonia at room temperature down to 1 ppm.Wed, 01 Jan 2014 00:00:00 GMThttps://prabakaranshankar.com/publications/zno-water-hyacinth-nanostructure/https://prabakaranshankar.com/publications/zno-water-hyacinth-nanostructure/Switching the spray-pyrolysis precursor solvent between water and ethanol tunes ZnO film thickness from 875 down to 150 nm, producing a distinctive water-hyacinth nanostructure along the way.Wed, 01 Jan 2014 00:00:00 GMThttps://prabakaranshankar.com/publications/annealed-zno-ethanol-sensor/https://prabakaranshankar.com/publications/annealed-zno-ethanol-sensor/Annealing transforms a zinc-dominant spray-deposited film into polycrystalline ZnO, and only the film annealed at 623 K gives a useful room-temperature ethanol response.Tue, 01 Jan 2013 00:00:00 GMThttps://prabakaranshankar.com/publications/zno-nanospheres-to-nanorods-morphology-transition-via-fe-doping/https://prabakaranshankar.com/publications/zno-nanospheres-to-nanorods-morphology-transition-via-fe-doping/Increasing iron-dopant concentration drives a clear shape transition in spray-deposited ZnO from rounded nanospheres to elongated nanorods, narrowing the optical band gap along the way.Tue, 01 Jan 2013 00:00:00 GMThttps://prabakaranshankar.com/publications/oxygen-sensing-characteristics-of-milled-metal-oxide-materials/https://prabakaranshankar.com/publications/oxygen-sensing-characteristics-of-milled-metal-oxide-materials/Silica and titanium dioxide powders made by stirred bead milling were pressed into pellets and separately deposited as thin films to compare their room-temperature oxygen response.Sun, 01 Jan 2012 00:00:00 GMT