Hu, Te Smith, Matthew D. Dohner, Emma R. Sher, Meng-Ju Wu, Xiaoxi Trinh, M. Tuan Fisher, Alan Corbett, Jeff Zhu, X.-Y. Karunadasa, Hemamala I. Lindenberg, Aaron M. Mechanism for Broadband White-Light Emission from Two-Dimensional (110) Hybrid Perovskites The recently discovered phenomenon of broadband white-light emission at room temperature in the (110) two-dimensional organic–inorganic perovskite (<i>N</i>-MEDA)­[PbBr<sub>4</sub>] (<i>N</i>-MEDA = <i>N</i><sup>1</sup>-methylethane-1,2-diammonium) is promising for applications in solid-state lighting. However, the spectral broadening mechanism and, in particular, the processes and dynamics associated with the emissive species are still unclear. Herein, we apply a suite of ultrafast spectroscopic probes to measure the primary events directly following photoexcitation, which allows us to resolve the evolution of light-induced emissive states associated with white-light emission at femtosecond resolution. Terahertz spectra show fast free carrier trapping and transient absorption spectra show the formation of self-trapped excitons on femtosecond time-scales. Emission-wavelength-dependent dynamics of the self-trapped exciton luminescence are observed, indicative of an energy distribution of photogenerated emissive states in the perovskite. Our results are consistent with photogenerated carriers self-trapped in a deformable lattice due to strong electron–phonon coupling, where permanent lattice defects and correlated self-trapped states lend further inhomogeneity to the excited-state potential energy surface. dynamic;energy surface;N 1;femtosecond resolution;energy distribution;photogenerated emissive states;lattice defects;Terahertz spectra show;MEDA;carrier;ultrafast spectroscopic probes;emissive species;emission;perovskite;absorption spectra show;deformable lattice;room temperature;exciton 2016-06-01
    https://acs.figshare.com/articles/journal_contribution/Mechanism_for_Broadband_White-Light_Emission_from_Two-Dimensional_110_Hybrid_Perovskites/3412387
10.1021/acs.jpclett.6b00793.s001