Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.
J Am Soc Mass Spectrom. 2020 Dec 2;31(12):2443-2451. doi: 10.1021/jasms.0c00153. Epub 2020 Sep 17.
Organic light emitting devices (OLEDs), especially in a screen display format, present unique and interesting substrates for laser desorption/ionization-mass spectrometry imaging (LDI-MSI) analysis. These devices contain many compounds that inherently absorb light energy and do not require an additional matrix to induce desorption and ionization. OLED screens have lateral features with dimensions that are tens of microns in magnitude and depth features that are tens to hundreds of nanometers thick. Monitoring the chemical composition of these features is essential, as contamination and degradation can impact device lifetime. This work demonstrates the capability of LDI-MSI to obtain lateral and partial depth resolved information on multicolored OLED displays and suggests the application to other mixed organic electronics with minimal sample preparation. This was realized when analyzing two different manufactured OLEDs, in an active-matrix display format, without the need to remove the cathode. By utilizing low laser energy and high lateral spatial resolution imaging (10 μm), depth profiling can be observed while maintaining laterally resolved information, resulting in a three-dimensional MSI approach that would complement existing OLED characterization methods.
有机发光二极管（OLED），特别是在屏幕显示格式中，为激光解吸/电离质谱成像（LDI-MSI）分析提供了独特而有趣的衬底。这些器件包含许多固有吸收光能的化合物，不需要额外的基质来诱导解吸和电离。OLED 屏幕具有数十微米量级的横向特征和数十到数百纳米厚的深度特征。监测这些特征的化学成分至关重要，因为污染和降解会影响器件的寿命。这项工作证明了 LDI-MSI 能够获得多色 OLED 显示器的横向和部分深度分辨信息，并提出了在其他混合有机电子设备中应用的建议，只需进行最小的样品制备。在分析两种不同的制造 OLED 时实现了这一点，采用有源矩阵显示格式，无需去除阴极。通过利用低激光能量和高横向空间分辨率成像（10 μm），可以在保持横向分辨信息的同时观察深度分布，从而实现了一种三维 MSI 方法，可以补充现有的 OLED 表征方法。
