Abstract We fabricated alternately multilayered films using CaF2 and ZnS with a different number of pairs by thermal evaporation method and evaluated their reflectance as a distributed Bragg reflector (DBR). A 7-pair CaF2/ZnS multilayered film had an enough high reflectance for use as DBR in the wavelength region of 400–600 nm, which is good agreement with the theoretically calculated reflectance. The fabricated CaF2/ZnS multilayered film was incorporated to the organic light-emitting diode (OLED) devices. We found that the inversed-type OLED (iOLED) structure is suitable for achieving the working device. From the result of electroluminescence (EL) measurement, the spectral linewidth of EL of inversed OLED with DBR (μ-cavity iOLED) was significantly narrowed compared to that of conventional OLED (cOLED). The EL peak wavelength of μ-cavity iOLED was centered around 520 nm, which was well corresponded to the designed cavity length. The observed narrowing of EL spectra for μ-cavity iOLED was originated from the microcavity effect. Color coordinate of the emission were changed from cOLED: (0.31, 0.54) to μ-cavity iOLED (0.20, 0.72), which indicates a significant improvement of color purity of green emission.

中文翻译：

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具有 CaF2/ZnS 分布式布拉格反射器的微腔有机发光二极管的制备和表征

摘要 我们使用不同对数的 CaF2 和 ZnS 通过热蒸发方法制造了交替多层薄膜，并评估了它们作为分布式布拉格反射器 (DBR) 的反射率。7 对 CaF2/ZnS 多层膜具有足够高的反射率，可用作 400-600 nm 波长范围内的 DBR，这与理论计算的反射率非常吻合。将制备的 CaF2/ZnS 多层膜结合到有机发光二极管 (OLED) 器件中。我们发现倒置型OLED（iOLED）结构适合实现工作装置。从电致发光（EL）测量结果来看，与传统OLED（cOLED）相比，具有DBR（μ-cavity iOLED）的反转OLED（μ-cavity iOLED）的EL光谱线宽显着变窄。μ 腔 iOLED 的 EL 峰值波长集中在 520 nm 附近，这很好地对应于设计的腔长。观察到的 μ 腔 iOLED 的 EL 光谱变窄源于微腔效应。发射色坐标从cOLED：(0.31, 0.54) 变为μ-cavity iOLED (0.20, 0.72)，表明绿色发射色纯度显着提高。