Fig. 6: Temperature-sensing in water environment.

a Schematic illustration of luminescence temperature-sensing based on TPP₃Cu₂Br₂ soaking in water. b PL decays of the TPP₃Cu₂Br₂ at different depths of water by monitoring the emission at 524 nm (λ_ex = 355 nm) at 37 °C. c PL emission spectra of the TPP₃Cu₂Br₂ at different depths of water upon 355 nm excitation at 37 °C. d Comparison of calculated temperatures at different depths of water from multiple experiments based on PL intensity and PL lifetime, where data were presented as average ± standard deviation calculated from three independently measured PL emission and PL lifetime spectra. e Error values between calculated and actual temperatures (37 °C) at different water depths