Highly enhanced sensitivity of optical oxygen sensors using microstructured PtTFPP/PDMS-pillar arrays sensing layer

- Novel PtTFPP/PDMS-MPA sensor film with unmatched sensitivity has been fabricated for the first time.
- The ultra-sensitive sensor film enable reliable monitoring DO within nanomolar concentration ranges.
- The ultra-sensitive sensor film facilitates convenient identification of O2 concentrations even with naked eye.
- The ultra-sensitive sensor film could be used in anoxic systems and unsteady flow visualization.

In this work, we presented a facile and cost-effective approach to fabricate novel PtTFPP/PDMS micro-pillar array (MPA) sensor film with I0/I100 for gaseous oxygen and dissolved oxygen are 288 and 84, respectively. The sensitivity of the sensor film exhibited over ∼30-fold increment when compared with contemporary PtTFPP/PDMS-based oxygen sensors. The detection limit was as low as 0.10 μmol/L, which means that the ultrasensitive sensor films enable reliable monitoring of dissolved oxygen (DO) within nanomolar concentration ranges that are particularly difficult to achieve in previous works. Furthermore, the remarkably light intensity-changing characteristic of the sensing film under lower O2 partial pressures facilitates convenient identification of O2 concentrations even with the naked eye. We believe that the proposed device could be a promising candidate in various oxygen sensing fields such as nearly anoxic systems, unsteady pressure measurement and unsteady flow visualization, etc.