Highly efficient blueish-green fluorescent OLEDs based on AIE liquid crystal molecules: From ingenious molecular design to multifunction materials

TY - JOUR

T1 - Highly efficient blueish-green fluorescent OLEDs based on AIE liquid crystal molecules

T2 - From ingenious molecular design to multifunction materials

AU - Wang, Yafei

AU - Liao, Yuanwei

AU - Cabry, Christopher P.

AU - Zhou, Di

AU - Xie, Guohua

AU - Qu, Zuoming

AU - Bruce, Duncan W.

AU - Zhu, Weiguo

PY - 2017/4/28

Y1 - 2017/4/28

N2 - In order to seek the balance point between liquid crystallinity and high efficiency emission, two novel aggregation-induced emission-based (AIE) liquid crystal materials of TPE-PBN and TPE-2PBN, which contain a tetraphenylethene derivative as the emission core and a 4-cynobiphenyl moiety as the mesogenic unit, were designed and prepared. Both simple molecules showed a mesophase at high temperature as evidenced by polarised optical microscopy (POM), differential scanning calorimetry (DSC) and temperature-dependent X-ray diffraction (XRD). Simultaneously, TPE-PBN and TPE-2PBN presented clear AIE characteristics in the blueish-green region and achieved a high emission quantum efficiency of 71% and 83% in the solid state, respectively. Due to the self-assembly properties of thermotropic liquid crystals, both compounds showed higher hole mobilities in the annealed films than in pristine films. Employing TPE-PBN and TPE-2PBN as the emitting materials, both non-doped devices and doped devices were fabricated. The TPE-PBN-based doped OLEDs showed a better device performance with an external quantum efficiency (EQE) of 4.1% which is among the highest EQEs of blue AIE fluorescent OLEDs.

AB - In order to seek the balance point between liquid crystallinity and high efficiency emission, two novel aggregation-induced emission-based (AIE) liquid crystal materials of TPE-PBN and TPE-2PBN, which contain a tetraphenylethene derivative as the emission core and a 4-cynobiphenyl moiety as the mesogenic unit, were designed and prepared. Both simple molecules showed a mesophase at high temperature as evidenced by polarised optical microscopy (POM), differential scanning calorimetry (DSC) and temperature-dependent X-ray diffraction (XRD). Simultaneously, TPE-PBN and TPE-2PBN presented clear AIE characteristics in the blueish-green region and achieved a high emission quantum efficiency of 71% and 83% in the solid state, respectively. Due to the self-assembly properties of thermotropic liquid crystals, both compounds showed higher hole mobilities in the annealed films than in pristine films. Employing TPE-PBN and TPE-2PBN as the emitting materials, both non-doped devices and doped devices were fabricated. The TPE-PBN-based doped OLEDs showed a better device performance with an external quantum efficiency (EQE) of 4.1% which is among the highest EQEs of blue AIE fluorescent OLEDs.

UR - http://www.scopus.com/inward/record.url?scp=85017788791&partnerID=8YFLogxK

U2 - 10.1039/c7tc00034k

DO - 10.1039/c7tc00034k

M3 - Article

SN - 2050-7534

VL - 5

SP - 3999

EP - 4008

JO - Journal of Materials Chemistry C

JF - Journal of Materials Chemistry C

IS - 16

ER -