Electron injection plays a key role in electron–photon conversion properties of inverted UV–visible organic light-emitting diodes (OLEDs). Herein, facilely prepared solution-processed lithium carbonate (Li₂CO₃) formic acid and boric acid solutions for tailoring electron injection in inverted near-UV (NUV) OLEDs are studied. Superior film morphology and exceptional electronic properties of spin-coated Li₂CO₃ films are examined by atomic force microscopy, X-ray/ultraviolet photoelectron spectroscopy, current–voltage curves, and impedance spectroscopy. Efficient inverted NUV OLEDs are assembled using wide-bandgap molecule of 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole as emissive layer, showing maximum radiance of 5.24 mW cm⁻² (2.28 mW cm⁻²) and external quantum efficiency of 2.47% (2.17%) with an optimal Li₂CO₃ formic acid of 3 mg ml⁻¹ (Li₂CO₃ boric acid of 7 mg ml⁻¹) as electron injection tailoring. The NUV emission shows electroluminescence peaks of 404–406 nm and full width at half maximum of 52–56 nm. The results provide some feasible approaches for enhancing the performance of organic electronic devices, which require strong electron injection/extraction and accelerate industrialization.

中文翻译：

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用于定制高性能倒置近紫外有机发光二极管中的电子注入的简便溶液处理碳酸锂

电子注入在反向紫外可见有机发光二极管 (OLED) 的电子-光子转换特性中起着关键作用。在此，研究了简便制备的溶液处理碳酸锂 (Li ₂ CO ₃ ) 甲酸和硼酸溶液，用于定制倒置近紫外 (NUV) OLED 中的电子注入。通过原子力显微镜、X 射线/紫外光电子能谱、电流-电压曲线和阻抗谱检查旋涂 Li ₂ CO ₃薄膜的优异薄膜形态和卓越的电子特性。高效的倒置 NUV OLED 使用宽带隙分子 2-(4-biphenyl)-5-(4- tert-丁基苯基)-1,3,4-恶二唑作为发射层，显示出 5.24 mW cm ^-2 (2.28 mW cm ^-2 ) 的最大辐射率和 2.47% (2.17%) 的外量子效率以及最佳的 Li ₂ CO ₃甲酸3 mg ml ^{-1 的}酸（7 mg ml ^{-1 的}Li ₂ CO ₃硼酸）作为电子注入定制。NUV 发射显示 404-406 nm 的电致发光峰和 52-56 nm 的半峰全宽。该结果为提高有机电子器件的性能提供了一些可行的方法，这需要强电子注入/提取并加速工业化。