Fig. 2: Stability and photostability of the TTA-UC systems in air.
From: Molecular near-infrared triplet-triplet annihilation upconversion with eigen oxygen immunity
a The changes of upconversion emission intensities of IR806-BTTQD 1–3, IR806-rubrene, and PtOEP-DPA solutions during 7 days storage in air. b Photographic images of IR806-BTTQD 2 and IR806-rubrene solution over the 7-day storage in air. c Emission stabilities of upconversion in IR806-BTTQD 2, IR806-rubrene, and PtOEP-DPA solutions with/without degassing under continuous-wave laser irradiation at 808 or 532 nm. d Photographic images of TTA upconversion emission in (c) taken at varied time in aerated solution. IR806-BTTQD 1–3 and IR806-rubrene were dissolved in chloroform, while PtOEP-DPA was dissolved in tetrahydrofuran with concentrations of cIR806 = 1 × 10−5 M, cBTTQD = 1 × 10−4 M, cRubrene = 1 × 10−4 M, cPtOEP = 1 × 10−4 M, cDPA = 1 × 10−2 M. For IR806-BTTQD 1–3 and IR806-rubrene, λex = 808 nm, power density = 100 mW/cm2, while for PtOEP-DPA, λex = 532 nm, power density = 5 mW/cm2. An optical filter with 750 nm short pass was placed in front of the camera (iPhone 12, Apple Inc.) to accurately acquire the TTA-UC luminescence of IR806-rubrene and IR806-BTTQ 2 systems in (d).
