Identifying and controlling phase purity in 2D hybrid perovskite thin films
| Autor: | Laura Spies, Pablo Docampo, Harry Jones, Priyanka Mocherla, Piers R. F. Barnes, Jonas Hanisch, Thomas Bein, Yinghong Hu, Diego Alonso-Álvarez |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Photoluminescence Renewable Energy Sustainability and the Environment business.industry 02 engineering and technology General Chemistry Substrate (electronics) 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention Crystal Semiconductor Chemical engineering law Photovoltaics General Materials Science Crystallization Thin film 0210 nano-technology business Perovskite (structure) |
| Zdroj: | Journal of Materials Chemistry A. 6:22215-22225 |
| ISSN: | 2050-7496 2050-7488 |
| DOI: | 10.1039/c8ta05475d |
| Popis: | Two-dimensional (2D) hybrid perovskites have attracted considerable attention due to their enormous structural and electronical variability, making this class of semiconductors interesting for photovoltaics, light-emitting diodes and lasers. 2D perovskites consist of sheets of bulky organic cations alternately sandwiched by layers of lead halide octahedra. The properties of these materials strongly depend on the thickness of the octahedra layers, defined by the number of octahedra sheets in a layer, n. Consequently, controlling the layer thickness purity (i.e. minimizing the spread in n) is important for any 2D perovskite thin film application. Here, we show that using rationally chosen solvent additives in the precursor solution offers a facile way to control the crystal disorder in 2D perovskites films. Our method leads to significantly reduced variation in n around the target value relative to films obtained by conventional fast-crystallization methods without solvent additives. The improved phase purity in optimized n = 2 and n = 3 films is verified by X-ray diffraction, UV-vis absorption, and photoluminescence measurements. Additionally, we find that 2D perovskite films with n ≥ 2 arising from additive-assisted growth exhibit an unusual crystal orientation with the perovskite interlayers predominantly aligned parallel to the substrate, which we assign to the slow crystallization process induced by the lead-complexing solvent additives. Improved control over the phase purity translates into a better control of the optoelectronic properties of 2D perovskite films. Furthermore, the unusual horizontal crystal orientation of n = 2 and n = 3 films makes this family of tunable organic–inorganic perovskites promising for applications where lateral charge transport is desired, thus enlarging the potential for thin film-based applications of the 2D perovskites. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|