Ligand-Mediated Modulation of Layer Thicknesses of Perovskite Methylammonium Lead Bromide Nanoplatelets Academic Article uri icon

abstract

  • 2016 American Chemical Society. Organic metal halide perovskites have rapidly emerged as among the leading candidates for the next generation of photovoltaic and light-emitting devices. The band gap, exciton binding energy, and absorption cross-section of these materials are tunable to some extent by compositional variation. Dimensional confinement represents an attractive alternative to compositional variation for tuning these properties via quantum confinement close to the Bhr radius. While the stabilization of few-layered nanoplatelets of methylammonium lead bromide has recently been demonstrated, mechanistic understanding of synthetic parameters resulting in dimensional confinement remains to be developed. Here we show that the layer thickness can be precisely modulated as a function of the chain length and concentration of the added alkylammonium cations. Surface capping ligands bind preferentially to sheets of corner sharing PbBr 6 octahedra and thereby buffer the extent of supersaturation of monomeric units enabling precise modulation of the layer-by-layer growth of 2D nanoplatelets. Crystal growth can be confined to yield nanoplatelets with tunable unit cell thickness spanning between one and six layers, which allows for precise tuning of the emissive properties of 2D perovskite nanoplatelets in the range of 430-520 nm depending on the layer thickness. The results suggest a generalizable strategy for tuning the layer thickness of these materials as a function of the alkyl chain length of the ligands.

published proceedings

  • Chemistry of Materials

altmetric score

  • 3

author list (cited authors)

  • Cho, J., Choi, Y., OLoughlin, T. E., De Jesus, L., & Banerjee, S.

citation count

  • 67

complete list of authors

  • Cho, Junsang||Choi, Yun-Hyuk||O’Loughlin, Thomas E||De Jesus, Luis||Banerjee, Sarbajit

publication date

  • October 2016