There is much debate about whether the junction temperature or phosphor temperature is higher in white light-emitting diodes (LEDs). The main reason is that the junction and phosphor temperatures cannot be measured directly using traditional temperature measurement tools. In this study, a magnetic nanoparticle thermometer, a nondestructive and precise temperature measurement tool, is introduced and described in detail. The model, measurement principle, and experimental setup are described. The temperature of the phosphor layer and the top surface of the P-N junction in white LEDs was measured directly using the magnetic nanoparticle thermometer, and the results show that the phosphor layer temperature was higher than the chip top surface temperature at different input voltages, providing a reference for relative researchers.

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http://dx.doi.org/10.1063/1.4998728DOI Listing

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