Ultra-Stable Deep-Dyed Perovskite-Polymer Composites as Tunable Downconverters

Technology #34381

Key Points

  • Cost-effective, simple, scalable deep-dyeing strategy for luminescent perovskite-polymer composite (PPC) fabrication
  • Allows incorporation of perovskite nanoparticles in a more environmentally stable polymer (resistant to moisture, oxygen, and heat)
  • Enables displays to provide a large color gamut and high photoluminescence efficiency

Abstract

Researchers at the University of Central Florida have developed a low-cost, simple deep‐dyeing method that can convert a polyethylene terephthalate (PET) polymer matrix into ultra‐stable luminescent perovskite‐polymer composites (PPCs) that demonstrate water resistance and heat stability. Due to their excellent color tunability, color purity, and water‐/photo‐stability, the PPCs are usable in displays, solid‐state lighting, or other applications. The invention addresses a growing demand for improved, cost-saving manufacturing techniques that produce displays encompassing a large color gamut and high photoluminescence efficiency. With the invention, solid-state lighting (SSL) systems can meet specific lighting requirements while at the same time reducing or omitting unnecessary or even damaging portions of the spectrum. Applications include optical down-converters or emitters for display and lighting or active absorber or passive luminescent concentrators for solar photovoltaics.

Technical Details

The UCF invention comprises methods for fabricating stable, highly luminescent perovskite-polymer composites. It includes a swelling-deswelling encapsulation method involving three components:

  • Perovskite precursors
  • Solvents
  • Polymer substrates that swell when brought into contact with the solvents and deswell when the solvents are removed.

For example, a perovskite-precursor solution is prepared: PbBr2 and CH3NH3Br are combined with a molar ratio of 1:3 in dimethylformamide to yield MAPbBr3. The solution is processed directly onto a polymer matrix through spin coating, dip coating, slot-die coating, inkjet printing, spray coating, or cotton swab painting. Next, a solvent (such as dimethylformamide) penetrates the polymers, causing them to swell and absorb the perovskite precursors. Finally, the solvent is driven out of the polymer matrix (by baking at 25-120 degrees Celsius for 2-10 hours), leaving the perovskite-precursors within the polymer matrix to react and form high quality, well-dispersed luminescent perovskite nanocrystals.

As the polymer substrate deswells (shrinks back), it forms a coherent barrier layer around the perovskite nanocrystals. This barrier protects them from water and oxygen from the surrounding environment. The perovskite-polymer composites possess high optical qualities showing narrow emission peaks and high photoluminescence quantum yield (PLQY). Numerous types of perovskites, solvents, and polymers may be used if the polymers swell and deswell when solvents enter and exit them.

High color quality white-light generation was demonstrated using green emissive MAPbBr3-polymer composites and red CdSe-based quantum dots as down-converters of blue LEDs. The LEDs provided color gamut coverage of a record 95 percent of Rec 2020, the color standard for ultra-high definition (UHD) TVs.

Partnering Opportunity

The research team is looking for partners to develop the technology further for commercialization.

Stage of Development

Prototype available.

Benefit

  • Cost-effective methods for easily processing perovskite-polymer composites
  • Composites possess high photoluminescence quantum yield (PLQY) and high color purity showing a full width at half maximum (FWHM) of 20 nm to 30 nm

Market Application

  • Materials in flat panel displays
  • Non-linear optical/photoconductive devices
  • Chemical sensors
  • Emitting and charge-transporting layers in light-emitting diodes, solar cells
  • Channel layers in field-effect transistors