Deprotonation Process Modulated Compositional Transformation in ZnO-Based Red Perovskite Light-Emitting Diodes
Xiangru Tao1, Chang Yi1, Shuzhen Guan1
1State Key Laboratory of Flexible Electronics (LoFE) & Institute of Advanced Materials (IAM), School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, People's Republic of China.
The Journal of Physical Chemistry Letters
|May 14, 2025
Summary
This study reveals how ZnO electron transport layers improve mixed formamidinium-cesium (FA-Cs) perovskite LEDs. Interfacial deprotonation enhances perovskite quality, leading to efficient red LEDs with high external quantum efficiency.
Area of Science:
- Materials Science
- Optoelectronics
- Solid-State Chemistry
Background:
- Mixed cation perovskites (formamidinium-cesium, FA-Cs) are promising for light-emitting diodes (LEDs).
- ZnO electron transport layers (ETLs) enhance perovskite LED performance via deprotonation reactions with FA+ cations.
- The structural transformation mechanism in mixed iodide-bromide (I-Br) perovskites driven by deprotonation is not fully understood.
Purpose of the Study:
- To elucidate the deprotonation-driven structural transformation in mixed FA-Cs I-Br perovskites at the ZnO interface.
- To investigate the influence of ZnO layer thickness on this interfacial deprotonation process.
- To optimize mixed I-Br perovskite red LEDs by controlling interfacial properties.
Main Methods:
- Fabrication of mixed FA-Cs I-Br perovskite light-emitting diodes (LEDs) with varying ZnO ETL thicknesses.
- Investigation of interfacial deprotonation reactions using advanced characterization techniques (details not specified in abstract).
- Analysis of perovskite structural properties, cation ratios, and defect densities.
Main Results:
- Interfacial deprotonation, modulated by ZnO thickness, suppresses low-dimensional perovskite formation.
- The FA-Cs ratio at the A-site of the 3D perovskite decreases due to deprotonation.
- Defect density at the buried interface is significantly reduced.
- Achieved a mixed I-Br perovskite red LED with 11% external quantum efficiency and 6858 cd m-2 luminance.
Conclusions:
- Controlling interfacial deprotonation via ZnO ETL thickness is crucial for high-quality mixed FA-Cs I-Br perovskites.
- This approach effectively minimizes defects and undesirable low-dimensional phases, enhancing LED performance.
- Demonstrated a high-performance red perovskite LED, showcasing the potential of this interfacial engineering strategy.
