Cho Hyunsu, Chung Jin, Song Jinouk, Lee Jaeho, Lee Hyunkoo, Lee Jonghee, Moon Jaehyun, Yoo Seunghyup, Cho Nam Sung
Opt Express. 2019 Apr 15;27(8):11057-11068. doi: 10.1364/OE.27.011057.
The ratio of spontaneous emission inside a diode structure to that in free space is called the Purcell factor (F(λ)). The structure of organic light-emitting diodes (OLEDs) has a significant influence on the spontaneous emission rate of dipole emitters. Therefore, to describe the optical properties of OLEDs, it is essential to incorporate F(λ) in the description. However, many optical studies on OLEDs continue to be conducted without considering F(λ) for simplicity's sake. Hence, in this study, using carefully designed bottom- and top-emitting OLEDs, we show that the external quantum efficiency obtained without considering F(λ) can be over- or under-estimated, and in some cases, the margin of error may be significant. We also reveal that the subtle distribution of the electroluminescence spectrum can be explained properly only by including F(λ). Both these results stipulate the importance of including F(λ) to maintain a quantitative agreement between theoretical and experimental data. Hence, the inclusion of F(λ) is important for designing OLEDs with enhanced efficiency or desired spectral characteristics.
二极管结构内部的自发发射与自由空间中的自发发射之比称为珀塞尔因子（F(λ)）。有机发光二极管（OLED）的结构对偶极子发射器的自发发射率有重大影响。因此，为了描述OLED的光学特性，在描述中纳入F(λ)至关重要。然而，出于简化的目的，许多关于OLED的光学研究在进行时并未考虑F(λ)。因此，在本研究中，我们使用精心设计的底部和顶部发射OLED表明，在不考虑F(λ)的情况下获得的外部量子效率可能被高估或低估，在某些情况下，误差幅度可能很大。我们还揭示，只有纳入F(λ)才能正确解释电致发光光谱的细微分布。这两个结果都表明纳入F(λ)对于保持理论和实验数据之间的定量一致性很重要。因此，纳入F(λ)对于设计具有更高效率或所需光谱特性的OLED很重要。
