Doped crystalline thin-film deep-blue organic light-emitting diodes

Abstract

A doped crystalline thin-film deep-blue organic light-emitting diode (C-OLED) with high photon output and a low driving voltage is created through employing highly ordered and high-mobility organic semiconductor layers.

Crystalline organic thin films for crystalline OLEDs (I): orientation of phenanthroimidazole derivatives

“…The carriers can transport in the vertical direction with a hole mobility of 0.10 cm 2 V À1 s À1 and an electron mobility of 0.015 cm 2 V À1 s À1 , as measured in a previous study although the molecules adopt an edge-on arrangement on the substrate. 9 More importantly, the angle between the long axis and the substrate is 6.11 and the PPI moieties are perpendicular to the substrate. The electronic structures of 2FPPICz were calculated using density functional theory (DFT) in a previous study, 15 and the transition dipole moment was further calculated.…”

“…[5][6][7] However, high-performance OLEDs based on the crystalline route have not been widely realized even after many efforts. Recently, it was reported that efficient deep-blue luminescence has been achieved in crystalline OLEDs that consist of phenanthroimidazole derivatives, 8,9 which were fabricated via a facile physical vapor deposition technique, the weak epitaxy growth (WEG) method. 10,11 Phenanthroimidazole derivatives are a class of promising deep-blue light-emitting materials due to their advantages of having a wide-bandgap, bi-polar transport and high fluorescence quantum yield.…”

“…15 Moreover, the reported doped crystalline thinfilm OLED (C-OLED) that adopted 2FPPICz as the host material has demonstrated an excellent performance with the largest number of emitted photons in deep-blue OLEDs compared with all reported amorphous thin-film deep-blue OLEDs. 9 These promising properties are ascribed to the 2FPPICz crystalline thin films, which render a high mobility for superior charge transport and rapid exciton formation. Therefore, the 2FPPICz crystalline thin film can act as an ideal matrix for improving the emitting performance of devices and developing next-generation OLEDs.…”

High-efficiency blue-emission crystalline organic light-emitting diodes sensitized by “hot exciton” fluorescent nanoaggregates

“…The C-OLEDs are capable of achieving much enhanced photoemission at the same driving voltage in OLEDs, owing to the high carrier mobility of crystalline thin films and the resultant rapid formation of excitons (24,40). Figure 5A shows the comparison of the brightness of the CHM-HENA-D OLED (2 wt % DSA-Ph) with reported typical blue OLEDs with high EQE, of which the CIE y coordinate values are close to but less than 0.20 (41)(42)(43).…”

Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate

“…There was no need to introduce HILs for the ITO-based devices since it has been shown in the literature that increased O 2 plasma durations (≈15 min) increase the work function of the ITO to desired levels. [55,56] It is also known that O 2 plasma treatment can modify the work function of Gr; however, longer plasma treatment durations result in unpredictable detachment of the graphene layers. Hence a short O 2 plasma treatment (≈5 min) to remove organic contaminants was performed on the Grcoated PET substrates before PEDOT:PSS deposition.…”