Enhanced electroluminescence of cesium lead bromide light-emitting diode driven by ion migration via surface passivation with organic halide surfactants

• Main Author: Srisawad K.
• Other Authors: Mahidol University
• Format: Article
• Published: 2023
• Subjects: Chemistry
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/84189

One strategy to enhance the performance of perovskite light-emitting diode is to reduce the surface defect of the perovskite. In this work, we investigated the post treatment of CsPbBr3 perovskite polycrystalline film using three passivation agents: cetylpyridinium bromide (CPB), cetyltrimethylammonium bromide (CTAB), and hexadecylamine (HDA). The introduction of organic cationic functional groups on the CsPbBr3 surface helped remove the defects, causing less non-radiative recombination and therefore enhanced both photoluminescence and electroluminescence. Additionally, excess bromide ions on the perovskite surface supplied by CPB and CTAB further passivated and increased the radiative recombination. In all cases, the use of these passivation agents did not alter the band gap of the CsPbBr3 perovskite emitter, preserving the core material and its emission wavelength. To further understand the passivation mechanisms, a simple device fabricated without using a high vacuum evaporator was prepared with mesoporous ZrO2 insulating layer as a spacer between the anode and the cathode. Higher electroluminescence, voltage-independence recombination zone, as well as better stability were achieved with the passivation.