Quantaurus tau fluorescence lifetime measurement system

The current density-voltage-luminance (J-V-L) curves, Commission Internationale de l’Eclairage (CIE) 1931 color coordinate, and electroluminescence (EL) spectra were obtained by using a spectroradiometer (CS-2000, Konica Minolta). Photoluminescence (PL) spectra of 50 nm-thick EML films (DBFPO:DMAC-DMT(40%) and DPEPO:DMAC-DMT(40%)) were measured using fluorescence spectrophotometer (Hitachi F-7000) at room temperature. The photoluminescence quantum yields (PLQY) of the EML films were obtained from fluorescence spectrometer (JASCO FP-8500) installed with an integrated sphere. The transient PL decay curves of the EML films were recorded from Quantaurus-Tau fluorescence lifetime measurement system (C11367-03, Hamamatsu Photonics Co.) under N₂ atmosphere at room temperature. The exciton lifetimes of prompt and delayed components of the PL decay curves were calculated using single and triple-exponential decaying functions^{22 (link)}.

Toluene solutions containing these two materials (10⁻⁵M) were prepared to investigate their absorption and photoluminescence characteristics in the solution state. Thin-film samples (15% wt- doped in mCBP 100 nm) were deposited on quartz glass substrates by vacuum evaporation to study their exciton confinement properties in the film state. Ultraviolet–visible absorption (UV-vis) and photoluminescence (PL) spectra were recorded on a Perkin-Elmer Lambda 950 KPA spectrophotometer and a JobinYvon FluoroMax-3 fluorospectrometer. Phosphorescent spectra were recorded on a JASCO FP-6500 fluorescence spectrophotometer at 77 K. Absolute PL quantum yields were measured on a Quantaurus-QY measurement system (C11347-11, Hamamatsu Photonics) under nitrogen flow and all samples were excited at 360 nm. The transient PL decay characteristics of solution samples were recorded using a Quantaurus-Tau fluorescence lifetime measurement system (C11367-03, Hamamatsu Photonics). The prompt and delayed PL spectra of the samples were measured under a vacuum using a streak camera system (Hamamatsu Photonics, C4334) equipped with a cryostat (Iwatani, GASESCRT-006-2000, Japan). A nitrogen gas laser (Lasertechnik Berlin, MNL200) with an excitation wavelength of 337 nm was used.

The compounds HATCN, TAPC, TCTA, mCP, mCBP, PPF, TmPyPB, TPBi, Bpy-TP2, 4CzTPNBu, BCz-TRZ and DIC-TRZ were purchased from commercial sources. TCP-BP-SFAC and BDAMC-XT were synthesized according the published methods^{10 (link),38 (link)}. PL spectra were recorded by Horiba Fluoromax-4 spectrofluorometer, and UV-visible absorption spectra were taken from a Shimadzu UV-2600 spectrophotometer. Transient PL decay curves and fluorescence lifetimes were measured under nitrogen atmosphere at room temperature in a Quantaurus-Tau fluorescence lifetime measurement system (C11367-03, Hamamatsu Photonics Co., Japan).