Quantum dots for Chemical Industry

Key Properties: 

     High quantum yield; narrow emission FWHM (15–30 nm) 

Applications:

CdSe/ZnS core–shell quantum dots (QDs) with a total size of 15–30 nm are highly valued in industrial applications due to their:

• Size-tunable  fluorescence (500–650+ nm),
• High quantum yield (up to 80–90%),
• Photostability and chemical robustness (than

Key Properties: 

     High quantum yield; narrow emission FWHM (15–30 nm) 

Applications:

CdSe/ZnS core–shell quantum dots (QDs) with a total size of 15–30 nm are highly valued in industrial applications due to their:

• Size-tunable  fluorescence (500–650+ nm),
• High quantum yield (up to 80–90%),
• Photostability and chemical robustness (thanks to the ZnS shell),
• And surface modifiability for dispersion in organic or aqueous media.

These characteristics make them ideal for optoelectronics, biomedical imaging, sensing, and photovoltaics, among others. 

Industrial Applications of CdSe/ZnS Core–Shell Quantum Dots (15–30 nm)

1. 📺 Display and Lighting Technologies

a. Quantum Dot Light-Emitting Diodes (QD-LEDs / QLEDs)

• CdSe/ZnS QDs are used in:
  • TV displays
  • Monitors
  • Quantum dot backlit LCDs
• Provide:
  • High color purity
  • Wide  color gamut
  • High  brightness
• Tunable emission from blue to red based on CdSe core size.

b. Solid-State Lighting (SSL)

• Used in white LEDs as color converters to adjust emission spectrum precisely.

Commercial examples: Samsung QLED displays, Sony Triluminos TVs.

2. 🧬 Biomedical Imaging and Diagnostics

a. Fluorescence Imaging

• Used as stable fluorescent probes for:
  • Cell  tracking
  • Tumor labeling
  • Multicolor  bioimaging

b. Biosensing

• CdSe/ZnS QDs conjugated with biomolecules (e.g., antibodies, aptamers) enable:
  • Detection of proteins, DNA, toxins, cancer markers

c. Fluorescence Resonance Energy Transfer (FRET) Sensors

• Act as energy donors in FRET assays for high-sensitivity detection.

ZnS shell improves biocompatibility and reduces cytotoxicity compared to bare CdSe.

3. 🧪 Chemical and Environmental Sensing

• Functionalized QDs can detect:
  • Heavy metals (Hg²⁺, Pb²⁺)
  • Explosives
  • Pesticides
  • pH,  oxygen, or temperature changes
• Based on changes in fluorescence intensity, wavelength, or lifetime.

4. ⚡ Photovoltaics and Solar Energy

a. Quantum Dot-Sensitized Solar Cells (QDSSCs)

• CdSe/ZnS QDs serve as light-harvesting materials with broad-spectrum absorption.

b. Photocatalysis

• Used in water splitting, organic dye degradation, or CO₂      reduction when excited by sunlight or UV.

5. 🎨 Security Inks and Anti-counterfeiting

• Fluorescent QDs are used in invisible security inks:
  • Banknotes
  • Legal  documents
  • Product authentication labels

QDs emit bright, stable fluorescence under UV/blue light.

6. 🧪 Laser Technologies

• Used in QD lasers due to their narrow emission bandwidth and optical gain.
• Emit tunable wavelengths useful in fiber optics, communications, and laser pointers.

7. 🧴 Cosmetics and Personal Care (Emerging Use)

• Used for fluorescent makeup, nail polish, and smart mirror coatings (limited due to Cd toxicity concerns).

Key Properties:

    Tunable emission 520–700 nm; robust photostability 

Applications:

CdTe/CdS core–shell quantum dots (QDs) have a wide range of industrial and high-tech applications due to their tunable bandgap, strong photoluminescence, and improved stabilitycompared to bare CdTe QDs. The CdS shell passivates the core and enhances per

Key Properties:

    Tunable emission 520–700 nm; robust photostability 

Applications:

CdTe/CdS core–shell quantum dots (QDs) have a wide range of industrial and high-tech applications due to their tunable bandgap, strong photoluminescence, and improved stabilitycompared to bare CdTe QDs. The CdS shell passivates the core and enhances performance, making these nanomaterials suitable for several key sectors:  

Industrial Applications of CdTe/CdS Core–Shell Quantum Dots

1. 🔋 Photovoltaics (Solar Cells)

• Application: Used in quantum dot-sensitized solar cells (QDSSCs) and thin-film      photovoltaics.
• Function: CdTe/CdS QDs act as light harvesters with high absorption in the      visible spectrum.
• Advantages:
  • Tunable bandgap for efficient solar spectrum coverage.
  • Shell improves electron injection and reduces recombination.

    

2. 💡 Optoelectronics

• Applications:
  • Light-emitting diodes (QD-LEDs)
  • Lasers
  • Photodetectors
• Function: Emit bright, narrow-band light with color tunability based on size.
• Benefits:
  • High luminescence efficiency
  • Long-term stability due to CdS shell protection

    

3. 🧪 Bioimaging and Biosensing

• Application: Used as fluorescent probes in medical diagnostics, cellular imaging, and biosensors.
• Advantages:
  • Bright, stable emission for long-duration imaging
  • Surface can be functionalized with biomolecules
• Examples:
  • Imaging of cancer cells
  • DNA/protein detection
• ⚠️ Note: Due to cadmium toxicity, their use in biomedical      applications requires encapsulation or alternative low-toxicity  cores (e.g., InP/ZnS in clinical settings).

4. 🎨 Display Technologies

• Application:  Incorporated into quantum dot enhancement films (QDEFs) for:
  • TVs
  • Monitors
  • Smartphones
• Function:  provide pure colors, higher brightness, and improved energy efficiency.
• Note: CdTe/CdS QDs offer red or near-infrared emission.

5. 🌡️ Thermoelectric Devices

• Application: Used in waste heat recovery and energy harvesting systems.
• Function: Exploit quantum confinement to improve thermoelectric efficiency.
• Status: Still largely in research or prototype stages.

6. 🔬 Chemical and Environmental Sensors

• Application: Detection of metal ions, pH changes, gases, etc.
• Mechanism:     Photoluminescence changes upon binding to target analytes.
• Use   Case: Monitoring water contamination, especially for Hg²⁺,  Pb²⁺, and Cr⁶⁺ ions.   

Key Properties:

    Lower toxicity; visible emission 550–650 nm 

Applications:

 InP/ZnS quantum dots (QDs) are low-toxicity, high-performance nanomaterials that have emerged as viable alternatives to cadmium-based QDs (like CdSe/ZnS or CdTe/CdS) due to regulatory and environmental concerns over cadmium. 

The InP core provides size-tunable o

Key Properties:

    Lower toxicity; visible emission 550–650 nm 

Applications:

 InP/ZnS quantum dots (QDs) are low-toxicity, high-performance nanomaterials that have emerged as viable alternatives to cadmium-based QDs (like CdSe/ZnS or CdTe/CdS) due to regulatory and environmental concerns over cadmium. 

The InP core provides size-tunable optical properties, and the ZnS shell improves photoluminescence quantum yield, chemical stability, and biocompatibility. 

Industrial and Technological Applications of InP/ZnS Quantum Dots

1. 📱 Display Technologies (QD-LEDs and LCD Backlights)

• Used in: TVs, monitors, smartphones
• Function:  Incorporated into quantum dot films to enhance color purity and      brightness
• Advantages:
  • Narrow emission spectra (high color purity)
  • High brightness and energy efficiency
  • Cadmium-free (RoHS-compliant)
• Commercial      Use: Adopted in Samsung, LG, TCL and other QLED displays as an      eco-friendly alternative

2. 💡 Solid-State Lighting (White LEDs)

• Function: Combined with blue LEDs to produce white light with improved color  rendering index (CRI) and tunable color temperature
• Benefit: Better spectral control compared to traditional phosphors

3. 🧬 Biomedical Imaging and Diagnostics

• Application: Fluorescent labels for in vitro diagnostics, cell labeling,  and biomolecular imaging
• Advantages:
  • Low cytotoxicity compared to Cd-based QDs
  • Long-term fluorescence without photobleaching
• Surface modification allows conjugation with antibodies, peptides, etc.

⚠️ Note: Still limited in in vivo clinical use due to incomplete toxicological clearance—but promising in research and diagnostics.

4. 🔬 Biosensing

• Used in: Detection of DNA, proteins, heavy metals, enzymes
• Mechanism: Fluorescence quenching or enhancement upon binding to target molecules
• Examples:
  • pH sensors
  • Glucose sensors
  • Immunoassays

    

5. 🧪 Photocatalysis and Photodetectors

• Used in: Solar-driven water splitting, CO₂ reduction, photodetectors
• Benefit: InP/ZnS has suitable bandgap alignment for visible-light-driven processes

6. 🔋 Solar Energy and Photovoltaics

• Application: Quantum dot-sensitized solar cells (QDSSCs)
• Function: Tunable light absorption and efficient electron injection
• Challenge: Still under research for stability and cost scaling

7. 🎨 Printing and Anti-Counterfeiting

• Used  for: Security inks, QR code printing, and smart packaging
• Property: Bright, tunable fluorescence under UV/blue light