# Dual Minimization of Spectrum Overlap for High-Sensitivity, High-Temperature Sensing

## TL;DR

This paper introduces a new method for high-sensitivity temperature sensing by minimizing spectrum overlaps in dual emitters, leading to improved performance in wide temperature ranges.

## Contribution

The study proposes a novel design strategy for high-sensitivity thermometers by dual minimization of spectrum overlaps in energy transfer and emission.

## Key findings

- Dually minimizing spectral overlap of energy transfer and emission improves ratiometric thermosensing sensitivity.
- Enlarging emission separation between dual emitters is more effective than suppressing FRET or enhancing thermal decay contrast.
- The DBA-BPAc/Ir(MDQ)2(acac) film achieves a maximum relative sensitivity of 3.36% °C−1 at 166 °C.

## Abstract

What are the main findings?
Dually minimizing spectral overlap of both energy transfer and emission enables high-sensitivity ratiometric thermosensing.Enlarging the emission separation between dual emitters proves more decisive for enhancing sensitivity than suppressing FRET or enhancing thermal decay contrast.

Dually minimizing spectral overlap of both energy transfer and emission enables high-sensitivity ratiometric thermosensing.

Enlarging the emission separation between dual emitters proves more decisive for enhancing sensitivity than suppressing FRET or enhancing thermal decay contrast.

What are the implications of the main findings?
Providing new insights for understanding underlying mechanism in high-sensitivity thermometry.Providing a new design strategy for fabrication high-performance thermometers.

Providing new insights for understanding underlying mechanism in high-sensitivity thermometry.

Providing a new design strategy for fabrication high-performance thermometers.

Minimizing the spectrum overlaps of energy transfer (ET) is necessary but not sufficient for achieving high-sensitivity film thermosensing. Herein we have designed two blue emitters of DBA-BPAc and Z-DBABH exhibiting blue and bluish-green emissions, respectively, to hybridize with the red-emitting Ir(MDQ)2(acac). Compared with Z-DBABH, DBA-BPAc shows a larger spectrum overlap of ET and a relatively smaller discrepancy in fluorescence thermal decay, while its emission spectrum displays a much smaller overlap with that of Ir(MDQ)2(acac). The dual minimization of spectrum overlap of ET and emissions results in its superior ratiometric film thermosensing of the DBA-BPAc film in wide-range and high-temperature regions. The DBA-BPAc/Ir(MDQ)2(acac) film exhibits a maximum relative sensitivity (Sr) of 3.36% °C−1 at 166 °C, exceeding 0.43% °C−1 in 50–265 °C. In comparison, the Z-DBABH/Ir(MDQ)2(acac) system displays a reliable but relatively lower performance, with a maximum Sr of 1.92% °C−1 (at 300 °C). The temperature resolution remains below 2.06 °C throughout the entire temperature range (20–300 °C), achieving a best value of 0.60 °C at 180 °C. Notably, both films display distinct naked-eye color transitions with temperature changes, enabling multi-level anti-counterfeiting applications. This work provides new insights for designing high-performance thermometers.