Negative Thermal Quenching of Efficient White‐Light Emission in a 1D Ladder‐Like Organic/Inorganic Hybrid Material

Abstract

semiconducting properties as well as their ability to process materials using low temperature techniques. [6][7][8][9] Their crystal structures generally consist of layered metal halide sheets alternating with organic cations. The inorganic and organic components are linked by hydrogen bonds to form the perovskite-like structure. [10][11][12] White-light emission has been recently discovered in several 2D OIH layered perovskites and has been attributed to the self-trapping of excitons within the hybrid material. [13][14][15][16][17][18][19][20][21][22] This important discovery sets the stage for exploring white-light emitting diodes (WLEDs) based on such materials which exhibit a photoluminescence (PL) quantum yield (QY) that can reach 32.5%. [23] However, since the first reports of 1D OIH compounds in 1995 by Papavassiliou et al. and Mitzi et al.,[24,25] investigations of these low-dimensional materials have remained scarcely reported, despite their many benefits such as high exciton stability, strong quantum confinement, and their ability to combine various types of sharing metal halide octahedral within a single chain. Yet, it can be denoted that 1D materials have regained an increasing interest for the last 2 years The synthesis and the optical properties of a new organic-inorganic hybrid material (C 6 H 22 N 4 )[Pb 2 Br 8 ] (abbreviated as TETAPb 2 Br 8 ) is reported here.Its ladder-like crystal structure is built up from infinite 1D chains of cornersharing [Pb 2 Br 8 ] 4− bi-octahedra surrounded by tetra-protonated triethylenetetramine (abbreviated as TETA 4+ ) organic cations. Under UV excitation, this hybrid organic-inorganic compound emits white light due to radiative recombinations of self-trapped excitons associated with a structural distortion of the PbBr 6 octahedra. Thin films of TETAPb 2 Br 8 show a photoluminescence (PL) quantum yield of ≈11% and exhibit a Commission Internationale de l'Eclairage coordinates of (0.32, 0.37). In the low-temperature range, the PL intensity increases with increasing temperature. This negative thermal quenching of white-light emission is interpreted in terms of transitions between excitonic states involving an exciton-phonon interaction. The interpretations are supported by the temperature dependence of the resonant Raman scattering and by density functional theory calculations.

Highly Efficient Lead-Free (Bi,Ce)-Codoped Cs2Ag0.4Na0.6InCl6 Double Perovskites for White Light-Emitting Diodes

“…The initial increase in the PL intensity and the change in the shape of emission spectra with increasing temperature can be interpreted as the thermal population transfer between polaronic states associated with the distortion of the AgCl 6 octahedron. A similar thermal quenching behavior was also observed in (C 6 H 22 N 4 )­[Pb 2 Br 8 ] and GaAs …”

Optical anisotropy of one-dimensional perovskite C4N2H14PbI4 crystals

“…Shibata developed the multilevel radiative decay model to analyze the phenomenon [31]. In this model, the change of PL intensity with temperature is mainly caused by quenching effect [32]. The quenching effect is composed of several mechanisms: (1) thermal dissociation of the electron-hole pair [33], (2) with the temperature increasing, the excitons changing from the radiative self-trapped exciton states to the less radiative free exciton states [34], which leads to the decrease of the emission intensity with temperature increasing.…”

Halide Perovskite Nanocrystal Emitters

“…The negative emission TQ in the low‐temperature regime was also detected in a white‐light‐emitting low‐dimensional lead halide perovskite. [ 149 ]…”