title: Control of morphology, photoluminescence, and stability of colloidal methylammonium lead bromide nanocrystals by oleylamine capping molecules.
abstract: Methylammonium lead bromide (CH3NH3PbBr3) thin films and nanocrystals are useful for solar cells and LED applications. In order to improve stability in ambient environment, CH3NH3PbBr3nanocrystals have been synthesized using oleylamine as capping molecule. It was found that by increasing the oleylamine to CH3NH3PbBr3perovskite ratio (OPR), the photoluminescence wavelengths of CH3NH3PbBr3nanocrystals could be varied from 505nm (green) to 450nm (blue). The change in emission wavelength is associated with a morphology change from nanoplatelets of ∼10nm width at OPR<1 to nanoparticles of ∼3nm diameter at OPR>1. It is suggested that the morphology change of nanocrystals is a result of geometric packing constraint of the sizes of oleylamine and PbBr3octahedra. The nanocrystals with OPR=0.75 maintain photoluminescence property for more than 6months in ambient condition and can sustain temperature of 150°C for 30min.
authors: Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, United States.
authors: Cheng-Hsin
authors: CH
authors: Lu
authors: Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, United States.
authors: Jiaang
authors: J
authors: Hu
authors: School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, United States.
authors: Wan Y
authors: WY
authors: Shih
authors: Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, United States. Electronic address: shihwh@drexel.edu.
authors: Wei-Heng
authors: WH
authors: Shih
keywords: Capping molecule; Morphology; Oleylamine; Organolead halide perovskites; Stability