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Published on: September 8, 2017
Mixed-Halide Perovskites with Stabilized Bandgaps.
Zhengguo Xiao1, Lianfeng Zhao1, Nhu L Tran1
1Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Researchers stabilized mixed-halide perovskites using organic ammonium capping layers. This prevents phase separation, enabling efficient, tunable perovskite LEDs and improved solar cell voltage.
Area of Science:
- Materials Science
- Solid-State Physics
- Optoelectronics
Background:
- Organic-inorganic hybrid perovskites offer tunable bandgaps crucial for optoelectronic devices.
- Mixed-halide perovskites suffer from halide segregation under light or bias, limiting device performance (e.g., VOC pinning, infrared emission).
Purpose of the Study:
- To suppress halide redistribution in mixed-halide perovskites.
- To enable fabrication of stable, efficient, and wavelength-tunable perovskite-based optoelectronic devices.
Main Methods:
- Employed self-assembled long-chain organic ammonium capping layers on nanometer-sized grain surfaces.
- Investigated the effect of these capping layers on halide redistribution and perovskite film stability.
- Fabricated and characterized perovskite light-emitting diodes (LEDs) and solar cells.
Main Results:
- Successfully suppressed light- and bias-induced halide redistribution.
- Achieved efficient and wavelength-tunable perovskite LEDs (infrared to green) with high external quantum efficiencies (up to 5%).
- Demonstrated linearly tuned open-circuit voltage (VOC) from 1.05 to 1.45 V in solar cells.
Conclusions:
- Self-assembled organic ammonium capping layers effectively stabilize mixed-halide perovskites against phase separation.
- This stabilization enables the development of high-performance, tunable perovskite optoelectronic devices, including LEDs and solar cells.
- The approach offers a pathway to overcome key limitations in perovskite device applications.
