Notes on thermometric artefacts by Er3+ luminescence band interference

Optical thermometry based on the intensity ratio of the H-2(11/2) -> I-4(15/2) (525 nm) and S-4(3/2) -> I-4(15/2) (545 nm) emission of Er3+ provides a powerful tool for microscale temperature sensing. Crystalline beta-NaYF4:Er,Yb is an excellent thermometry material for green upconversion emission upon NIR laser excitation. However, interfering H-2(9/2) -> I-4(13/2) emission is observed around 555 nm for continuous-wave laser excitation intensities above 10 W/cm(2). In this study, the green Er3+ emission bands are characterized and it is demonstrated how the true sample temperature is determined circumventing possible artefacts.

Automated summary

This study explores optical thermometry based on the intensity ratio of the Er3+ emission bands and demonstrates how to accurately determine sample temperature circumventing possible artefacts. Crystalline beta-NaYF4:Er,Yb is identified as an excellent thermometry material for microscale temperature sensing with green upconversion emission, although interference from other emission bands is observed at high excitation intensities.