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Updated: Jul 15, 2025
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Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance
Published on: February 27, 2017
18.5K
Vacuum Deposited Perovskites with a Controllable Crystal Orientation.
Jin Yan1,2, Lena Sophie Stickel1,3, Lennart van den Hengel2
1PVMD Group, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands.
The Journal of Physical Chemistry Letters
|September 25, 2023
Summary
Controlling perovskite (PVK) crystal orientation via thermal evaporation is crucial. Intermediate annealing temperatures enable tuning PVK (100) orientation, enhancing photoluminescence and surface homogeneity for better charge extraction.
Area of Science:
- Materials Science
- Solid-State Physics
- Optoelectronics
Background:
- Perovskite (PVK) orientation is key for optoelectronic properties, typically controlled via wet processing.
- Controlling crystal orientation in thermally evaporated PVK films remains underexplored.
- The impact of crystal orientation on charge carrier mobility, lifetime, and trap densities in evaporated PVK is not well understood.
Purpose of the Study:
- To investigate the effect of intermediate annealing temperatures on the crystal orientation of thermally evaporated perovskite films.
- To analyze how different crystal orientations influence the optoelectronic properties of these films.
- To determine if controlled orientation can enhance PVK film performance for device applications.
Main Methods:
- Sequential thermal evaporation of Cs0.15FA0.85PbI2.85Br0.15 with varying intermediate annealing temperatures (Tinter).
- X-ray Diffraction (XRD) and 2D-XRD to characterize crystal orientation.
- Photoconductivity, photoluminescence (PL) yield and lifetime measurements.
- Kelvin Probe Force Microscopy (KPFM) for contact potential difference (CPD) mapping.
Main Results:
- No intermediate annealing yielded predominantly (110) orientation.
- Tinter = 100 °C resulted in nearly isotropic orientation.
- Tinter > 130 °C led to highly oriented (100) PVK films.
- Bulk electronic properties (photoconductivity) were orientation-independent.
- Surface properties, including PL yield, lifetime, and surface potential homogeneity (via KPFM), significantly improved with (100) orientation.
Conclusions:
- Intermediate annealing is an effective method to control crystal orientation in thermally evaporated PVK.
- Highly oriented (100) PVK films exhibit superior photoluminescence and surface uniformity.
- Controlled (100) orientation is advantageous for improving charge extraction efficiency in perovskite devices.
