This thesis investigates the preparation and application of water-stable perovskite nanocrystals in luminescent temperature sensing on microfluidic chips, and the photothermal detection on microreactors by luminescent temperature sensing spots.

In Chapter 2, we show a new luminescent temperature sensor based on perovskite composite films and integrated with digital microfluidic platforms to perform the thermal mapping. A Hyflon fluoropolymer was applied to encapsulate CsPbBr₃ nanocrystals and form water-resistant perovskite composite films with long-term stability in water over 4 months and, more importantly, strong thermal stability between 20 and 80 °C with high temperature sensitivity (1.2% K^-1). CsPbBr₃ nanocrystal-Hyflon films were further incorporated as temperature sensing laye...[ Read more ]

This thesis investigates the preparation and application of water-stable perovskite nanocrystals in luminescent temperature sensing on microfluidic chips, and the photothermal detection on microreactors by luminescent temperature sensing spots.

In Chapter 2, we show a new luminescent temperature sensor based on perovskite composite films and integrated with digital microfluidic platforms to perform the thermal mapping. A Hyflon fluoropolymer was applied to encapsulate CsPbBr₃ nanocrystals and form water-resistant perovskite composite films with long-term stability in water over 4 months and, more importantly, strong thermal stability between 20 and 80 °C with high temperature sensitivity (1.2% K^-1). CsPbBr₃ nanocrystal-Hyflon films were further incorporated as temperature sensing layers on digital microfluidic platforms. Thermal mapping with a CsPbBr₃ nanocrystal-Hyflon film showed an increase in local temperatures of up to 40.2 °C upon voltage-driven droplet manipulations in a digital microfluidic system.

In chapter 3, we report a room-temperature synthesis of water-resistant CsPbBr₃ nanocrystals with the coordination of Hyflon and fluorinated silanols. CsPbBr₃ photoluminescence quantum yield at 73%, long luminescence lifetime (207 ns), and strong water resistance for one month at least. The obtained CsPbBr₃ nanocrystals also presented a temperature sensitivity of 1.01% K^-1 in aqueous media. Moreover, the whole process was completed at room temperature and ambient atmosphere.

A photothermal detection in microreactors integrated with a luminescent temperature sensing spot is introduced in Chapter 4. The tris(1,10-phenanthroline)ruthenium(II) temperature probe was immobilized in microchannels to quantify the photothermal heating with a temperature sensitivity of 1.4% K^-1 between 20 and 80 °C. The linearly increased temperature was observed with the increasing concentration of Amaranth dye in microchannels. The online monitoring of the synthesis of polydopamine nanoparticles was also successfully realized by detecting their photothermal effect, resulting in an increase of temperature up to 12 K under different conditions.