A Negative-Thermal-Quenching Phosphor Achieved by Energy Transfer

Abstract

Phosphor-converted white light-emitting diodes (pc-wLEDs) are drawing ever-increasing attention towards electronic applications. However, thermal quenching, the intensity decay with increasing temperature, presents a significant challenge for high power operation. We reverse the effect with a negative-thermal-quenching property based on energy transfer from one luminescent center to another center. The LaMgAl11O19: Er3+, Sm3+ (LMA: LaMgAl11O19: Er3+, Sm3+) phosphor has been designed, which shows a positive relationship between emission intensity and operating temperature up to 573 K (300 °C). As the temperature rises, energy transfer from Er3+ to Sm3+ occurs with higher efficiency because of stronger ionic vibration. As a result, the phosphor luminescence intensity at elevated temperatures is enhanced. Our design for negative-thermal quenching phosphor represents a strong candidate for application in high-power pc-wLEDs or lasers at higher temperatures. It also has potential for wide-temperature-sensing-range radiometric optical thermometry applications.

Keywords: negative-thermal-quenching, Energy transfer, Phosphors, wLEDs