Dual Optical Sensing of Temperature and Low Oxygen Partial Pressure Using a Thermally Activated Delayed Fluorescence Organic Material

High Resolution Image Download MS PowerPoint Slide Although luminescent materials enable noninvasive optical sensing for biomedical and industrial applications, their implementation remains limited by narrow operating ranges, complex synthesis and low sensitivity. Here, we present NAPAcI, a luminescent material that functions as a dual optical sensor for pressure and temperature. Under UV excitation, its photoluminescence shows strong dependence on oxygen pressure and temperature. The emission response was calibrated using an extended Stern−Volmer equation for ratiometric sensing. The remarkable sensing performance is attributed to thermally activated delayed fluorescence, enhanced by the heavy-atom effect of the iodine substituents. This design promotes ultrafast intersystem crossing on the subnanosecond scale and reverse intersystem crossing within tens of nanoseconds, while significantly reducing the prompt fluorescence rate, thereby tailoring the material for air-pressure sensing. Consequently, NAPAcI exhibits low measurement uncertainty, high repeatability, and robust performance. These results position NAPAcI as a cost-effective platform for optical pressure and temperature monitoring.