Crystallisation behaviour of CH3NH3PbI3 films: The benefits of sub-second flash lamp annealing
| Autor: | Bernd Szyszka, Stefan Seeger, Carola Klimm, Ralph Kraehnert, Sri Hari Bharath Vinoth Kumar, Markus R. Wagner, Ruslan Muydinov |
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| Rok vydání: | 2018 |
| Předmět: |
Flash-lamp
Materials science Silicon Annealing (metallurgy) Metals and Alloys chemistry.chemical_element Infrared spectroscopy 02 engineering and technology Surfaces and Interfaces 010402 general chemistry 021001 nanoscience & nanotechnology Microstructure 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Crystallinity Xenon chemistry Chemical engineering law Materials Chemistry Crystallization 0210 nano-technology |
| Zdroj: | Thin Solid Films. 653:204-214 |
| ISSN: | 0040-6090 |
| DOI: | 10.1016/j.tsf.2018.03.050 |
| Popis: | Crystallisation of the spin-coated hybrid perovskite films has some basic issues restraining the up-scaling of this technology. The reason consists in substantial chemical impact of the solvent during drying that lessens control of crystallisation and reproducibility. This current investigation proposes very fast crystallisation by means of a flash lamp to solve those issues. CH3NH3PbI3 films were prepared on glass and silicon substrates by spin-coating from N,N-dimethylformamide based solutions with various CH3NH3I to PbI2 ratios (1:1, 2:1 and 3:1). Thermal annealing of as-deposited films at 85 °C, 120 °C and 140 °C was compared with the flash lamp annealing realised via sub-second high energy xenon light illumination from the uncoated glass side. Optimal light pulse length and energy density were found to be 2.7 ms and 8 J/cm2, respectively. According to our simulations based on the finite element model the perovskite layers underwent to a short-term heating to 350–425 °C followed by cooling to 100 °C within 3 ms. No decomposition of the perovskite was detected. Conversely its crystallinity according to the X-ray diffraction was prominently better as for thermally annealed films. Fourier-transform infrared spectroscopy revealed the effective elimination of the solvent from perovskite films by flash lamp annealing. High temperature was found to be crucial for the completeness of PbI2 reaction into the perovskite in stoichiometric films. High heating rate appeared to suppress the gel-like phase formation in super-stoichiometric films that helped to avoid the formation of pores. The flash lamp crystallised films revealed pore free microstructure with longitudinally extended grains regardless of the precursor ratio. |
| Databáze: | OpenAIRE |
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