Crystals (Dec 2021)

A 3D Lead Iodide Hybrid Based on a 2D Perovskite Subnetwork

  • Maroua Ben Haj Salah,
  • Justine Tessier,
  • Nicolas Mercier,
  • Magali Allain,
  • Antonin Leblanc,
  • Xiaoyang Che,
  • Claudine Katan,
  • Mikael Kepenekian

DOI
https://doi.org/10.3390/cryst11121570
Journal volume & issue
Vol. 11, no. 12
p. 1570

Abstract

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Lead halide perovskites have emerged as promising materials for various optoelectronic applications. For photovoltaics, the reference compound is the 3D perovskite (MA)PbI3 (MA+ = methylammonium). However, this material suffers from instabilities towards humidity or light. This makes the search of new stable 3D lead halide materials very relevant. A strategy is the use of intermediate size cations instead of MA, which are not suitable to form the 3D ABX3 perovskites or 2D perovskites. Here, we report on a novel 3D metal halide hybrid material based on the intermediate size cation hydroxypropylammonium (HPA+), (HPA)6(MA)Pb5I17. We will see that extending the carbon chain length from two CH2 units (in the hydroxylethylammonium cation, HEA+) to three (HPA+) precludes the formation of a perovskite network as found in the lead and iodide deficient perovskite (HEA,MA)1+xPbxI3−x. In (HPA)6(MA)Pb5I17 the 3D lead halide network results from a 2D perovskite subnetworks linked by a PbI6 octahedra sharing its faces. DFT calculations confirm the direct band gap and reveal the peculiar band structure of this 3D network. On one hand the valence band has a 1D nature involving the p orbitals of the halide. On the other, the conduction band possesses a clear 2D character involving hybridization between the p orbitals of the metal and the halide.

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