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Aryl-substituted phenanthroimidazole (PI) and triphenylamine (TPA) derivatives have attracted tremendous attention in the field of opto-electronic devices because they possess excellent properties. In this work, we synthesized a novel organic emitting material ((E)-N,N-diphenyl-4-(4-(1-phenyl-1H-phenanthro [9,10-d]imidazole-2-yl)styryl)aniline (DPPyPA) with D–π–A chromophore. DPPyPA was synthesized without using precious metal catalysis. What's more, the reaction process was simple and easy to monitor. The photoelectric, physical properties and the organic/inorganic hybrid LED based on DPPyPA were investigated. The hybrid LED exhibits tunable electroluminescent spectra (EL) as the concentration of DPPyPA increases without losing device performance. In addition, the hybrid LED with low concentration of DPPyPA possesses luminance efficiency (LE) of 20 lm W−1 and greenish-blue emission. The hybrid WLEDs based on DPPyPA and Rubrene were also prepared. The device shows max Ra-color rendering index (Ra) of 73.5 and max LE of 32.64 lm W−1. It is a decent choice to establish organic/inorganic hybrid WLEDs by using greenish-blue emitting material and Rubrene.

1-(9-Anthryl)-2-phenylethene (t-APE) is a blue-green material with high fluorescence quantum yield (Фf 0.44). However, it is easily crystallized. Herein, Two asymmetric blue-green emitting materials based on t-APE, (E)-9-(4-(2-(anthracen-9-yl)vinyl)phenyl)-10-(naphthalen-1-yl)anthracene (6) and (E)-9-(4-(2-(anthracen-9-yl)vinyl)phenyl)-10-(naphthalen-2-yl)anthracene (7) were firstly designed and synthesized. The two compounds possess high thermal stability, morphological durability, and bipolar characteristics. The non-doped blue-green organic light-emitting diodes (OLEDs) using 6 and 7 as emitting layers showed emission at 495 nm, full width at half maximum of 80 nm, maximum brightness of 13,814, 10,579 cd m−2, maximum current efficiency of 3.62, 7.16 cd A−1, and Commission Internationale de L'Eclairage (CIE) coordinate of (0.20, 0.43), respectively. Furthermore, when employing 6 and 7 as blue-green emitting layers and rubrene doped in tris-(8-hydroxyquinolinato)aluminum (Alq3) as the orange emitting layers to fabricate white OLEDs (WOLEDs), the WOLEDs exhibit a maximum brightness of 10,984, 14,652 cd m−2, maximum current efficiency of 2.04, 2.70 cd A−1, and CIE coordinate of (0.30, 0.40), (0.37, 0.47), Color Rendering Index (CRI) of 65, 60, stable EL spectra, respectively. This study demonstrates that the t-APE-type derivatives have the excellent properties for the emitting materials of OLEDs.

The π–π stacking ability of graphene sheets (GS), graphene oxide (GO), and single walled carbon nanotubes (SWCNT) with phthalocyanine (Pc) molecules was studied by the UV–vis absorption, steady state and time-resolved fluorescence spectra. Absorption spectra revealed that strong π–π binding with the Pc ground state (S0) occurred for GS and GO but not for SWCNT, the binding ability is GS ≫ GO ≫ SWCNT. However, when a Pc molecule is photoexcited, fluorescence study shows that the π–π interaction capability is changed to GS ≫ SWCNT ≫ GO. Although SWCNT exhibits low ability to bind Pc S0 state, it strongly interacts with Pc S1 state. The data analysis shows that the dynamic quenching for the nanoscaled carbon quenchers still obeys linear Stern–Volmer relationship, but the static quenching is not linear. An exponential expression is needed to fit the data for GS and SWCNT, which indicates that an effective quenching sphere model is valid for the nanoscaled fluorescence quenchers.

The aggregation (inter-layer π–π interaction) and self-rolling up (intra-layer π–π interaction) of chemically derived graphene (CDG) sheets in aqueous dispersion were evidenced by spectral and TEM methods. Their effects on optical properties were studied by UV–vis–NIR absorption spectra, fluorescence emission spectra and fluorescence lifetime measurements under various CDG concentrations. At pH 8.3, CDG sheets formed carbon nanoscrolls by self-rolling up when its concentration is lower than 10 μg/mL. When the concentration is higher than that, CDG sheets aggregated. Upon aggregation, CDG exhibited the decrease of absorptivity, the change of band shape and the deviation from Lambert–Beer law due to inter-layer π–π interaction. The aggregation effect on CDG fluorescence includes the decrease of emission efficiency, the shortening of fluorescence lifetime and the relative increase of the contribution from short-lived emitting species. On the other hand, CDG self-rolling up caused the occurrence of new absorptions (500 and 960 nm) and new emission (after 500 nm), the decrease of fluorescence quantum yield and shortening of fluorescence lifetime.