Abstract
Halide double perovskites are an interesting alternative to Pb-containing counterparts as active materials in optoelectronic devices. Low-dimensional double perovskites are fabricated by introducing large organic cations, resulting in organic/inorganic architectures with one or more inorganic octahedra layers separated by organic cations. Here, we synthesized layered double perovskites based on 3D Cs2AgBiBr6, consisting of double (2L) or single (1L) inorganic octahedra layers, using ammonium cations of different sizes and chemical structures. Temperature-dependent Raman spectroscopy revealed phase transition signatures in both inorganic lattice and organic moieties by detecting variations in their vibrational modes. Changes in the conformational arrangement of the organic cations to an ordered state coincided with a phase transition in the 1L systems with the shortest ammonium moieties. Significant changes of photoluminescence intensity observed around the transition temperature suggest that optical properties may be affected by the octahedral tilts emerging at the phase transition.
Highlights
Halide double perovskites are an interesting alternative to Pb-containing counterparts as active materials in optoelectronic devices
I n the last years, metal-halide perovskites have attracted considerable interest for the development of nextgeneration optoelectronic devices because of their outstanding figures of merit in photovoltaics, exceeding 23% power conversion efficiency (PCE),[1] and in light emitting devices (LEDs), with nearly 100% internal quantum efficiency,[2] together with defect tolerance, low-cost solution processing, and tunable emission across the visible spectrum.[3−5] these devices suffer from severe limitations, such as low ambient stability,[4] ion migration under operation,[4,6] and the presence of toxic Pb.[4]
We studied layered double perovskites derived from Cs2AgBiBr6 by focusing on the influence of the organic cation layer on the optical and vibrational properties
Summary
The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Author Contributions ¶B.M-G. and D.S. contributed . G.B. and S.A. performed the DFT modeling. Notes The authors declare no competing financial interest
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