Self‐Healing Perovskite Films Enabled by Fluorinated Cross‐Linked Network Targeting Flexible Light‐Emitting Diode

Abstract

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.

Electronically Manipulated Molecular Strategy Enabling Highly Efficient Tin Perovskite Photovoltaics

“…This indicates that NH 2 group and F 3 group can interact with the perovskite, whereas CH 3 group does not exhibit such interactions. [24,25] After establishing the anchoring issue, we will focus on the diverse effects of molecular dipole moments in different orientations on the buried interface. As shown in Figure 2a, two distinct coupling agent molecules were employed for buried interface modification in the perovskite layer.…”

In Situ Cross‐Linking Strategy to Enable Highly Stable Perovskite Solar Cells

“…Zang et al. [ 137 ] introduced a cross‐linkable silane molecule of (3,3,3‐trifluoropropyl) trimethoxysilane (TFPTMS) into a perovskite precursor, which can be polymerized as elastic polymer net‐work in grain boundaries of perovskite. Intriguingly, the reversible hydrolysis and condensation reactions and the fluorinated alkyl chains endowed the perovskite films with self‐healing capability.…”

“…Reproduced with permission. [ 137 ] Copyright 2022, Wiley‐VCH. c) Schematic diagram of hybrid cross‐linked network and its mechanical‐energy‐dissipation and self‐healing mechanism.…”

“…Additionally, the cracks formed at perovskite films under stimuli of external mechanical stress can be self-healed by reasonably designed functional groups of cross-linkable additives, which can boost the mechanical stability of F-PSCs. Zang et al [137] introduced a cross-linkable silane molecule of (3,3,3-trifluoropropyl) trimethoxysilane (TFPTMS) into a perovskite precursor, which can be polymerized as elastic polymer net-work in grain boundaries of perovskite. Intriguingly, the reversible hydrolysis and condensation reactions and the fluorinated alkyl chains endowed the perovskite films with self-healing capability.…”

“…AFM images of perovskite film with TFPTMS a) before and b) after self-healing process. Reproduced with permission [137]. Copyright 2022, Wiley-VCH.…”