Advanced approach for phosphor recovery and characterization of LED components

Area of Science:

• Materials Science
• Analytical Chemistry
• Environmental Science

Background:

• Light Emitting Diodes (LEDs) are prevalent in lighting and electronics.
• Characterizing the complex composition of LEDs is crucial for recycling and material recovery.
• Existing methods often struggle to accurately quantify individual components like phosphors and metals.

Purpose of the Study:

• To introduce a novel analytical approach for the precise characterization of individual LED components.
• To develop a method for selectively recovering phosphors embedded in polydimethylsiloxane (PDMS).
• To determine the gravimetric composition of various LED components from diverse sources.

Main Methods:

• Disassembly of various LED types (SMD, COB, filament) from commercial and discarded sources.
• Selective phosphor recovery from PDMS via depolymerization using tetrabutylammonium fluoride (TBAF/THF).
• Elemental analysis using Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX) and Inductively Coupled Plasma - Atomic Emission Spectroscopy (ICP-AES) after aqua regia leaching.

Main Results:

• Identified key elements in phosphors (Y, Sr, Eu, Lu, Ce, Al, Ga, Ca) and metallic bodies (Au, Ag, Ni, Cu, Fe).
• Located Titanium (Ti) in LED housings.
• Successfully quantified the gravimetric composition of phosphors, PDMS, metallic fractions, and housings.

Conclusions:

• The developed method enables accurate compositional analysis of LED components.
• This approach facilitates efficient material recovery and recycling of valuable elements from LEDs.
• The study provides a foundation for understanding the material flows in LED waste streams.