Review—A Review on Phosphor in Glass as a High Power LED Color Converter

Abstract

Phosphor-in-glass (PiG) is a mixture of a transparent glass and ceramic phosphors and has been recently commercialized for its various advantages as an inorganic color converter for white light emitting diodes (wLEDs). Since the successful demonstration of the wLED and its improved stability over the conventional phosphors in silicon or organic resins, extensive studies have been reported to improve its color conversion and resultant LED properties, such as luminescence efficacy, chromaticity, correlated color temperature and color gamut, as well as its long term stability. Various attempts have also been made to fabricate a PiG structure and to extend its applications. This study reviews the recent progress of PiG and discusses various approaches that have been proposed to overcome the technical issues related to PiG.

Recycled Glass and Ce‐Doped‐Y3Al5O12 Nanoparticles Phosphor‐in‐Glass for White Light‐Emitting Diodes Applications

“…To a certain extent, pores are beneficial to the scattering of the excitation light within the glass matrix to reach the phosphor particles without decreasing the nanocomposite transmittance, but large pores will hinder light transmission. [ 5 ] At higher magnifications, the light gray regions are constituted by smaller particles of YAG:Ce, as shown in Figure 2f for RGY5‐800 PiG.…”

“…Coupling of an indium gallium nitride (InGaN) blue‐emitting chip (460 nm) and a highly efficient green‐yellow emitting phosphor (530 nm), such as Y 3 Al 5 O 12 :Ce 3+ yttrium aluminum garnet (YAG:Ce), is one of the widely used configurations of commercially available white light‐emitting diodes (WLEDs). [ 1–5 ] Silicone resins or organic binders are often used as a transparent matrix for phosphor encapsulation, even though they are low cost and easy to apply, their poor thermal and chemical stability, and UV light resistance hinders the color quality of the WLED. [ 5–9 ] Phosphor‐in‐glass (PiG) is one of the emerging materials to use instead of the phosphor‐in resin color converters for the WLED technology, albeit its favorable physical and chemical properties, they are less expensive and reproducible at manufacture.…”

“…[ 1–5 ] Silicone resins or organic binders are often used as a transparent matrix for phosphor encapsulation, even though they are low cost and easy to apply, their poor thermal and chemical stability, and UV light resistance hinders the color quality of the WLED. [ 5–9 ] Phosphor‐in‐glass (PiG) is one of the emerging materials to use instead of the phosphor‐in resin color converters for the WLED technology, albeit its favorable physical and chemical properties, they are less expensive and reproducible at manufacture. [ 10,11 ] However, a high temperature processing can compromise phosphor integrity and, thus, its luminescent properties and the luminous efficacy of the light‐emitting diode (LED).…”

“…[ 10,11 ] However, a high temperature processing can compromise phosphor integrity and, thus, its luminescent properties and the luminous efficacy of the light‐emitting diode (LED). [ 5 ] For this purpose, glasses of low‐melting temperature such as tellurites and boro‐tellurites, such as TeO 2 –ZnO–Na 2 O and TeO 2 –Na 2 O–ZnO–B 2 O 3 glass systems, have been used to preserve YAG:Ce luminescent properties after PiG processing, and other oxides, such as Sb 2 O 3 and Al 2 O 3 , can be added. [ 11–16 ] Typically, PiG using TeO 2 ‐based glasses is fabricated by sintering (below 800 °C) a mixture of YAG:Ce and the designed inorganic low‐melting glass frits at an optimal temperature.…”

A review on the structural dependent optical properties and energy transfer of Mn4+ and multiple ion-codoped complex oxide phosphors

“…To meet the requirement for indoor illumination, warm white light with a high color rendering index (CRI > 80) and a low correlated color temperature (CCT < 4000 K) is necessary. 17,18 Accordingly, phosphors with strong absorption in the blue light region and intense emission in the red light region should be co-coated on blue semiconductor GaN chips to produce warm white light. Mn 4+ ions located at octahedral crystallographic sites are favorable luminescent centers and promising for blue GaNexcited warm WLED applications because they have narrowband red emissions, broad-band blue excitations, and no reabsorption in white light, while being free of expensive rare earth metals.…”