Efficient charge-carrier injection and transport in organic light-emitting devices (OLEDs) are essential to simultaneously achieving their high efficiency and long-term stability. However, the charge-transporting layers (CTLs) deposited by various vapor or solution processes are usually in amorphous forms, and their low charge-carrier mobilities, defect-induced high trap densities and inhomogeneous thickness with rough surface morphologies have been obstacles towards high-performance devices. Here, organic single-crystalline (SC) films were employed as the hole-transporting layers (HTLs) instead of the conventional amorphous films to fabricate highly efficient and stable OLEDs. The high-mobility and ultrasmooth morphology of the SC-HTLs facilitate superior interfacial characteristics of both HTL/electrode and HTL/emissive layer interfaces, resulting in a high Haacke’s figure of merit (FoM) of the ultrathin top electrode and low series-resistance joule-heat loss ratio of the SC-OLEDs. Moreover, the thick and compact SC-HTL can function as a barrier layer against moisture and oxygen permeation. As a result, the SC-OLEDs show much improved efficiency and stability compared to the OLEDs based on amorphous or polycrystalline HTLs, suggesting a new strategy to developing advanced OLEDs with high efficiency and high stability.

有机发光器件 (OLED) 中的高效载流子注入和传输对于同时实现高效率和长期稳定性至关重要。然而，通过各种蒸气或溶液工艺沉积的电荷传输层（CTL）通常呈无定形形式，其载流子迁移率低、缺陷引起的高陷阱密度以及表面形貌粗糙的不均匀厚度一直是实现高电荷传输层的障碍。性能设备。这里，采用有机单晶（SC）薄膜代替传统的非晶薄膜作为空穴传输层（HTL）来制造高效且稳定的OLED。 SC-HTL 的高迁移率和超光滑形态有利于 HTL/电极和 HTL/发射层界面的优异界面特性，从而实现超薄顶部电极的高哈克品质因数 (FoM) 和低串联电阻焦耳-SC-OLED 的热损失率。此外，厚而致密的SC-HTL可以充当阻挡湿气和氧气渗透的屏障层。因此，与基于非晶或多晶 HTL 的 OLED 相比，SC-OLED 显示出大大提高的效率和稳定性，这提出了开发具有高效率和高稳定性的先进 OLED 的新策略。