Efficient control on the growth of organic crystalline films is crucial for developing organic electroluminescent devices. Herein, a highly crystalline thin film of a blue-light-emitting material, 1,2-diphenyl-1H-phenanthro[9,10-d]imidazole (PPI) derivative, 1,4-bis(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzene (ρ-DPPI), has been achieved by the weak epitaxy growth (WEG) method. The ρ-DPPI molecules with an edge-on orientation grow epitaxially on the inducing layer, forming the continuous and uniform crystalline thin film. The photoluminescence (PL) spectrum of the ρ-DPPI thin film fabricated by weak epitaxy growth was blue-shifted relative to that of the amorphous ρ-DPPI thin film. Also, its PL quantum yield was measured and found to be 64.5%. The electroluminescence performance was evaluated and a fluorescent OLED that emits deep-blue light with Commission Internationale de L'Eclairage (CIE) coordinates of (0.15, 0.11) has been achieved. The device exhibits high performance with a maximum current efficiency, power efficiency and external quantum efficiency of 4.5 cd A⁻¹, 4.1 lm W⁻¹ and 4.1% at 200 cd m⁻², which demonstrates its potential as a highly efficient emitter. The further adoption of the WEG method would advance the knowledge of the growth behavior of luminescent materials and provide desired properties for their electroluminescent applications.

有效控制有机晶体膜的生长对于开发有机电致发光器件至关重要。在此，蓝色发光材料的高结晶性薄膜是1,2-二苯基-1H-菲并[9,10-d]咪唑（PPI）衍生物，1,4-双（1-苯基-1H-菲咯[9,10-d]咪唑-2-基）苯（ρ- DPPI）已通过弱外延生长（WEG）方法实现。具有边沿取向的ρ- DPPI分子在诱导层上外延生长，形成连续且均匀的晶体薄膜。通过弱外延生长制造的ρ- DPPI薄膜的光致发光（PL）光谱相对于非晶ρ的光谱发生了蓝移-DPPI薄膜。另外，测量其PL量子产率，发现为64.5％。评估了电致发光性能，并且获得了发出深蓝色光的荧光OLED，其国际照明委员会（CIE）坐标为（0.15，0.11）。该器件具有高性能与最大电流效率，功率效率和4.5光盘的外部量子效率^-1，4.1流明w ^ ^-1和以200cd米4.1％^-2，这表明其潜在的作为高效发射极。WEG方法的进一步采用将增进对发光材料生长行为的了解，并为其电致发光应用提供所需的性能。