{
  "id": 12197408,
  "title": "Waste plastic yields carbon quantum dots with emissions tunable from UV to yellow-green",
  "url": "https://urgent.news/2026/10/05/waste-plastic-yields-carbon-quantum-dots-with-emissions-tunable-from",
  "topic": "science",
  "section": "Science",
  "published": "2026-10-05T17:20:12.000Z",
  "source": {
    "name": "Phys.org",
    "slug": "phys-org",
    "url": "https://phys.org/news/2026-10-plastic-yields-carbon-quantum-dots.html"
  },
  "original_language": "en",
  "account": "This research demonstrates that waste polyamide can be converted into carbon quantum dots (CQDs) with tunable photoluminescence ranging from UV to yellow-green. By modifying the surface chemistry of CQDs derived from polyamide through dry pyrolysis and various synthesis routes, the emission wavelength can be systematically shifted. The study achieved a 244 nm tuning range using the same polyamide precursor throughout. Controlled defect-state engineering allowed for precise regulation of optical emission, with emission wavelengths ranging from 308 nm to 552 nm and a quantum yield up to 62.74%. Two empirical descriptors, the defect-state depth index (Dindex) and the defect-state engineering index (DSEI), were introduced to quantify how emissive states evolved across the CQD series. These findings suggest that waste-derived CQDs could be tailored for specific optical applications, providing a new way to utilize plastic waste while advancing nanomaterial design.",
  "summary": "A research team from Saitama University has discovered a method to systematically control the photoluminescence of carbon quantum dots (CQDs) using waste polyamide as a single carbon precursor. By modifying the surface chemistry of CQDs through oxidation and incorporating heteroatoms such as boron, nitrogen, sulfur, and phosphorus, the researchers were able to shift the emission wavelength from the ultraviolet region (308 nm) to the yellow-green region (552 nm), achieving a tuning range of 244 nm. This breakthrough demonstrates that controlled defect-state engineering can regulate the optical emission of waste-polyamide-derived CQDs, paving the way for the development of high-value optical materials and applications in sensing, optoelectronics, displays, anticounterfeiting, and environmental technologies.",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}