Search

Perovskite light‐emitting diodes (PeLEDs) are promising technologies for advanced display and lighting source applications. Alongside tremendous efforts to improve efficiency, developing flexible devices could potentially enable PeLEDs compatible with wearable, foldable, bio‐integrated, and other intriguing functionalities. However, the flexible PeLEDs currently have not received enough attention. The overall performance still lags behind the rigid one, mainly attributed to the lack of mechanically stable perovskite thin films with desirable optical and electrical properties. Herein, a self‐healing strategy to achieve flexible perovskite films with improved mechanical reliability and optoelectrical properties is proposed. A multi‐functional silane molecule of (3,3,3‐trifluoropropyl) trimethoxysilane (TFPTMS) is incorporated into a perovskite precursor, which could undergo an in situ cross‐linking process and generate a flexible Si–O–Si network within the perovskite films. In addition, the reversible hydrolysis and condensation reactions and the fluorinated alkyl chains endow the perovskite films with self‐healing capability. Accordingly, the synergistic influences contribute to high‐efficiency flexible PeLEDs with an external quantum efficiency (EQE) of 16.2%. Moreover, 75% of the initial efficiency value is reserved even after 1000 bending cycles. This work paves a way to rationalize flexible perovskite thin films for various optoelectronic applications. [ABSTRACT FROM AUTHOR]

Defect passivation has been demonstrated to be effective in improving the radiative recombination of charge carriers in perovskites, and consequently, the device performance of the resultant perovskite light‐emitting diodes (LEDs). State‐of‐the‐art useful passivation agents in perovskite LEDs are mostly organic chelating molecules that, however, simultaneously sacrifice the charge‐transport properties and thermal stability of the resultant perovskite emissive layers, thereby deteriorating performance, and especially the operational stability of the devices. We demonstrate that lithium halides can efficiently passivate the defects generated by halide vacancies and reduce trap state density, thereby suppressing ion migration in perovskite films. Efficient green perovskite LEDs based on all‐inorganic CsPbBr3 perovskite with a peak external quantum efficiency of 16.2 %, as well as a high maximum brightness of 50 270 cd m−2, are achieved. Moreover, the device shows decent stability even under a brightness of 104 cd m−2. We highlight the universal applicability of defect passivation using lithium halides, which enabled us to improve the efficiency of blue and red perovskite LEDs. [ABSTRACT FROM AUTHOR]