Low Temperature Photochemical Sol-Gel Processing of Functional Thin Films and their Applications

该项目旨在开发功能无机薄膜在其低温溶液处理过程中的精确控制的通用方法，以实现柔性电子产品的卷到卷制造。今年，人们发现溶液处理的非晶态金属-有机薄膜锌(II)甲氧基乙氧基锌(ZME)在倒置有机发光二极管(IOLED)中起到了高效而稳定的电子注入层(EIL)的作用。相反，通过真空紫外光照射或高温退火法获得的结晶氧化锌都会导致很强的电子泄漏，从而降低了器件的效率。直流电容分析表明，Ag-ZME具有高度的介电行为，使其能够选择性地将电子注入到有机层的LUMO中，同时防止非发射的直接空穴还原。甲氧基乙氧基钙(CME)也被用作EIL进行比较，尽管其具有很强的绝缘性能，但在iOLED中表现出几乎与ZME相同的性能。利用Ag-CME和Ag-ZME中Ca(II)和Zn(II)的4s轨道来调节电子注入，这些见解提供了一种新的设计策略，利用非晶态介质金属-有机薄膜作为EILS，可能产生高性能、灵活和稳定的电子器件，如iOLED和钙钛矿型太阳能电池。

The project aims to develop general methodologies for the precise control of functional inorganic thin films in their low temperature solution processing for the realization of roll-to-roll fabrication of flexible electronics. This year, it was found that solution-processed amorphous metal-organic thin film zinc(II) methoxyethoxide (ZME) acts as an efficient and stable electron injection layer (EIL) in inverted organic light-emitting diodes (iOLEDs). In contrast, crystallized ZnO obtained either by utilizing vacuum ultraviolet (VUV) light irradiation or by high temperature annealing caused a strong electron leakage, reducing device efficiency. DC capacitance analysis revealed that ag-ZME has a highly dielectric behavior, allowing it to selectively inject electrons into the LUMO of the organic layer while preventing non-emissive direct reduction of holes. Calcium(II) methoxyethoxide (CME) was also employed as an EIL for comparison and showed nearly the same performance as ZME in iOLEDs, despite its strongly insulating properties. The 4s orbitals of Ca(II) and Zn(II) in ag-CME and ag-ZME are used to regulate the electron injection, these insights offer a new design strategy that uses amorphous dielectric metal-organic thin films as EILs, which may yield high-performance, flexible, and stable electronic devices, such as iOLEDs and perovskite solar cells.