{"paper":{"title":"Ion Concentration and Voltage Imaging with Fluorescent Nanodiamonds","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"Fluorescent nanodiamonds enable optical imaging of voltage and ion concentrations via NV charge-state switching.","cross_cats":[],"primary_cat":"cond-mat.mes-hall","authors_text":"Anita Quigley, Hiroshi Abe, Nikolai Dontschuk, Patrick Voorhoeve, Philipp Reineck, Qiang Sun, Rob Kapsa, Takeshi Ohshima","submitted_at":"2026-02-15T03:26:06Z","abstract_excerpt":"The nitrogen-vacancy (NV) center in diamond exists in different charge states with distinct photoluminescence properties, which are sensitive to the nanoscale electrochemical environment. Hence, the NV charge state is emerging as a powerful all-optical platform for nanoscale sensing and imaging. Although significant progress has been made in engineering near-surface NV centers in bulk diamond, controlling the NV charge state in fluorescent nanodiamonds (FNDs) has proven challenging, limiting the sensitivity and reliability of FND-based charge state sensing. Here, we demonstrate reliable, rever"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"In aqueous electrochemical cells, we demonstrate voltage and ion concentration imaging based on the NV charge state in self-assembled FND layers on transparent substrates. Applied voltages reliably modulate the FND PL with a sensitivity of up to 16 mV Hz^{-1/2}. FND PL is also modulated by local changes in salt concentration with a sensitivity of up to 1.8% per millimolar NaCl.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The observed photoluminescence modulation is caused by controlled switching between NV^0 and NV^+ charge states rather than other surface or environmental effects such as pH drift or temperature changes in the aqueous cell.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Fluorescent nanodiamonds enable all-optical imaging of voltage (up to 16 mV Hz^{-1/2}) and ion concentration (1.8% per mM NaCl) via reversible NV charge state switching in aqueous cells.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Fluorescent nanodiamonds enable optical imaging of voltage and ion concentrations via NV charge-state switching.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"921fcc1435445fef762536befb4f1b697fe2c9829fe5ac0f9447c74551502b87"},"source":{"id":"2602.13975","kind":"arxiv","version":3},"verdict":{"id":"8b580672-bc66-4405-9e9e-cb62c953e3cc","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T22:25:49.205958Z","strongest_claim":"In aqueous electrochemical cells, we demonstrate voltage and ion concentration imaging based on the NV charge state in self-assembled FND layers on transparent substrates. Applied voltages reliably modulate the FND PL with a sensitivity of up to 16 mV Hz^{-1/2}. FND PL is also modulated by local changes in salt concentration with a sensitivity of up to 1.8% per millimolar NaCl.","one_line_summary":"Fluorescent nanodiamonds enable all-optical imaging of voltage (up to 16 mV Hz^{-1/2}) and ion concentration (1.8% per mM NaCl) via reversible NV charge state switching in aqueous cells.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The observed photoluminescence modulation is caused by controlled switching between NV^0 and NV^+ charge states rather than other surface or environmental effects such as pH drift or temperature changes in the aqueous cell.","pith_extraction_headline":"Fluorescent nanodiamonds enable optical imaging of voltage and ion concentrations via NV charge-state switching."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2602.13975/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}