Cathodoluminescence spectroscopy of organic-inorganic perovskites
Lew, Kar Cheng
Date of Issue2018
School of Physical and Mathematical Sciences
Photonics Research Centre
Centre for Disruptive Photonic Technologies
In this work, cathodoluminescence (CL) techniques was applied to hybrid perovskite materials to identify relationship between their crystallographic microstructure and emission properties. The cathodoluminescence spectra of MAPbI3 and CsPbBr3 were compared against conventional photoluminescence spectra. Furthermore, interesting quasi two-dimensional organic-inorganic perovskites were studied with this technique. A bulky cation phenylethylammonium (PEA=C8H9NH3) was used to induce the formation of layered perovskites of the Ruddlesden-Popper series, and the dimensionality (n) of the resulting (PEA)2(MA)n-1 [PbnI3n+1] was tuned by adjusting the ratio of methylammonium iodide to PEA iodide. Steady-state and fast (ps) time-resolved cathodoluminescence spectroscopy were employed for the first time to correlate spatially resolved yield and dynamics of the luminescence with the complex phase distribution of multidimensional perovskite polycrystalline film. It was found that phase separation occurs into two preferential domains, corresponding to low- and high-dimensional perovskite rich areas. In this film, charge transfer and energy funnelling effects allow compositional control of the emission energy and recombination dynamics.