Morphology enhancement of self-assembled CH3NH3PbI3 nanoparticles through customized solvent evaporation temperatures

• Published in: Journal of crystal growth 2023-01, Vol.601, p.126970, Article 126970
• Main Authors: Bagherzadeh-Khajehmarjan, Elnaz, Nikniazi, Arash, Olyaeefar, Babak, Ahmadi-kandjani, Sohrab, Nunzi, Jean-Michel
• Format: Article
• Language: English
• Subjects: A1. Morphology; A1. Nanostructures; A1. Photoluminescence; A2. Self-assembly; B1. Perovskites
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2022.126970

•Self-assembly of CH3NH3PbI3 perovskite nanoparticles is recognized.•Different drying temperatures are observed to induce different morphologies.•Self-assembled structures show anisotropic photoluminescence.•Perovskites dried at higher temperatures show red-shifted photoluminescents.•Up-conversion emission confirms optical nonlinearity in the self-assembled samples. The CH3NH3PbI3 perovskite nanoparticles are synthesized by the sonication method. It is observed that the perovskite nanoparticles are self-assembled upon solvent evaporation. Differing the drying temperatures induces different morphologies. Confirmed with the repeated experiments, a reproducible approach for acquiring enhanced morphologies and larger grain sizes is established. Perovskite nanoparticles dried at 80 °C had edge-less tetragonal-like shapes and samples dried at 120 °C possessed cubic structures with a crystalline order extending 500 nm. Whereas, solvent evaporation from iodide perovskite dried at room temperature did not yield any ordered morphology. Self-assembled nanostructures showed anisotropic photoluminescence emission that confirms ordered assembly of the structures. Perovskites dried at 80 °C had the highest degree of photoluminescence emission polarization, which is due to their anisotropic micro-crystalline structure. According to FTIR results, the interaction of methylammonium cation with PbI cage in lead iodide perovskites is influenced by temperature treatments, leading to altered crystalline structure and hence diverse morphologies. Furthermore, all of the self-assembled perovskites were highly photo luminescent with slight red-shifts in samples dried at higher temperatures. We also observed up-conversion emission with a 1064 nm excitation, which confirms the existence of nonlinear response in these perovskite structures.