US 12187940 B1Patent grantUnited States

Heat-Free Bismuth Oxyhalide Quantum Dots

Official patent title

Method for making bizmuth oxyhalide quantum dots

Arabic title: طريقة تصنيع نقاط كمومية من أوكسي هاليد البزموت

Invention

Problem

Conventional bismuth oxyhalide synthesis often uses solvothermal treatment, autoclaves, reflux, or other time- and energy-intensive steps, limiting straightforward quantum-dot production.

Why it matters

A simpler low-temperature route could make bismuth-based quantum dots easier to investigate for visible-light photocatalysis, sensing, and other nanomaterial devices.

Approach

The method forms bismuth oxyhalide quantum dots in one pot without added heat by combining a bismuth-salt solution, an aqueous alkali-halide solution, and an aqueous surfactant solution, followed by filtration and optional drying.

Who may benefit

Potential beneficiaries include quantum-dot researchers, photocatalyst developers, sensor and solar-material laboratories, nanomaterial manufacturers, and specialty chemical producers.

Potential value

The disclosure offers a short, solution-based, no-added-heat formation route with defined salts, solvents, surfactants, mixing times, crystal size, surface area, band gap, and a 1:1 Bi:I molar ratio.

Background

Quantum dots offer size-dependent optical and electronic properties, but many established systems use metals such as Cd, Pb, or Hg, and their manufacture can require demanding thermal processing. Bismuth oxyhalides, particularly BiOI, are visible-light-responsive semiconductors considered for photocatalysis, sensors, and solar-energy research. Conventional BiOI routes commonly employ solvothermal treatment, autoclave incubation, microwave heating, or reflux. The patent addresses this process burden with a room-temperature wet-chemical route intended to control small crystal size and surface characteristics without adding heat during particle formation.

Technology overview

A bismuth salt, including Bi(NO3)3, is dissolved in polyethylene glycol, methylene glycol, triethylene glycol, or ethylene glycol. An alkali iodide, bromide, or chloride is dissolved in water, and the solutions are combined before addition to an aqueous polyoxyethylene-sorbitan surfactant. Mixing occurs for 5–10 and 10–15 minutes at 15–25 °C, followed by vacuum filtration; drying may use 100–115 °C. Claimed particles have 59–82 m2/g surface area, 1.80–2 eV band gap, 1–10 nm crystal size, and Bi:I of 1:1.

Potential applications

Potential use in visible-light photocatalysis research.
Potential use in optical or chemical sensor development.
Potential use in solar-energy and photoelectrochemical materials research.
Potential use as a bismuth-based quantum-dot platform for nanomaterial devices.

Evidence-supported advantages

Forms the quantum dots without added heat during the solution-mixing stage.
Uses a one-pot wet-chemical sequence with short specified mixing times.
Defines several compatible bismuth, halide, solvent, and surfactant options.
Claims nanometer crystal size together with specified surface-area and band-gap ranges.

Development stage

Patent publication with a described synthesis route and reported material characterization; commercialization and independent application-performance validation were not established.

Commercial opportunity

The synthesis route may support licensing or collaborative scale-up with quantum-dot, photocatalyst, sensor, or specialty-material companies. Required validation includes yield and batch consistency, particle-size control, photocatalytic benchmarking, surfactant removal, storage stability, impurity and leaching analysis, application-specific safety, and manufacturability at larger volumes.

Patent classifications

WIPO IPC

C09K11/74Materials for applications not otherwise provided for; applications of materials not otherwise provided for
C01G29/00Compounds containing metals not covered by subclasses C01D or C01F

CPC

C01G29/00Compounds containing metals not covered by subclasses C01D or C01F
C09K11/7428Materials for applications not otherwise provided for; applications of materials not otherwise provided for

Inventors

First inventorBabiker Y. Abdulkhair
InventorFaisal K. Algethami
InventorMohamed R. Elamin

Keywords

bismuth oxyhalide
quantum dots
BiOI
room-temperature synthesis
photocatalysis
visible light
surfactant
nanomaterials

Patent document and drawings

The patent publication is mapped to this record. Patent drawings remain within that publication; no separately cleared public media package has been supplied.