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Monitors, televisions, and smartphones have been revolutionized by the invention of InGaN-based LED backlighting. Yet, regular exposure to the bright blue light emitted by these screens can lead to mood disorders and insomnia. Switching to a "human-centric" display that uses a violet-emitting LED chip and a trichromatic phosphor blend is one materials chemistry solution for this problem. The challenge is finding a blue-emitting phosphor with a sufficiently small Stokes’ shift to down-convert the violet LED light. This study reports a new oxynitride phosphor that meets this need. K3AlP3O9N:Eu2+ exhibits a narrow (45 nm, 2206 cm-1), thermally robust, and efficient blue photoluminescence upon violet excitation. Computational modeling and photoluminescence spectroscopy revealed that a rare combination of preferential excitation and site-selective quenching produce the desired optical properties. Combining K3AlP3O9N:Eu2+ with red- and green-emitting phosphors and a violet LED covers 10% more of the color gamut than a commercial tablet while simultaneously mitigating blue light exposure en route to next-generation, human-centric displays.

The proliferation of energy-efficient light-emitting diode (LED) lighting has resulted in continued exposure to blue light, which has been linked to cataract formation, circadian disruption, and mood disorders. Blue light can be readily minimized in pursuit of "human-centric" lighting using a violet LED chip (λem ≈ 405 nm) downconverted by red, green, and blue-emitting phosphors. However, few phosphors efficiently convert violet light to blue light. This work reports a new phosphor that meets this demand. Na2MgPO4F:Eu2+ can be excited by a violet LED yielding an efficient, bright blue emission. The material also shows zero thermal quenching and has outstanding chromatic stability. The chemical robustness of the phosphor was also confirmed through prolonged exposure to water and high temperatures. A prototype device using a 405 nm LED, Na2MgPO4F:Eu2+, and a green and red-emitting phosphor produces a warm white light with a higher color rendering index than a commercially purchased LED light bulb while significantly reducing the blue component. These results demonstrate the capability of Na2MgPO4F:Eu2+ as a next-generation phosphor capable of advancing human-centric lighting.

The host structure of the new phosphor Sr6(BO3)3BN2:Eu2+ crystallizes tetragonally (Sr6(BO3)3BN2, P42/mbc, Z = 8, a = 12.8173(3) A, b = 14.0740(5) A, Rint = 0.037, R1 = 0.052, and wR2 = 0.121) and ...

The dual emission produced from Mn2+ when codoped with rare earth ions like Eu2+ or Ce3+ in inorganic compounds makes these materials attractive as efficient, color-tunable phosphors for warm-white...

Phosphor-converted light emitting diodes (LEDs) are a highly efficient form of solid-state lighting. A key performance metric of a phosphor is its thermal quenching (TQ), which is the percentage lo...

The photoluminescence spectrum generated by an ordinary phosphor-converted white light-emitting diode (pc-wLED) that combines a blue LED chip with a yellow phosphor or a near-UV LED with red, green...

One of society’s grand challenges is to reduce energy usage in ways that are cost-effective, sustainable, and environmentally benign. Replacing incandescent and compact fluorescent light bulbs with...

The production of white light based on a near-UV LED chip requires incorporating three inorganic phosphors that emit in the blue, green, and red portions of the visible spectrum. Using a near-UV LED has the advantage of generating a light with excellent color quality, but due to the large Stokes’ shift between the LED excitation and the multiple phosphor emissions, these devices can suffer from a low overall efficiency. To minimize this inherent energy loss, the three phosphors employed to convert the LED emission must be very efficient, as measured by the internal photoluminescent quantum yield (Φ). In this work, we report the synthesis of a cubic borate, Ba3Y2B6O15, which when substituted with Ce3+ becomes an efficient blue phosphor. This compound can be prepared using a multistep high temperature solid state synthesis with the ensuing photoluminescent measurements revealing a broad excitation band (300–415 nm) making this phosphor compatible with a 365 or 400 nm LED chip. Ba3Y2B6O15:Ce3+ luminesces bri...