SCHEDULED MAINTENANCE
Hybrid lead halide [(CH3)2NH2]PbX3 (X = Cl− and Br−) hexagonal perovskites with multiple functional properties†
*a
Emilio Jose
Juarez-Perez,
bc
Juan Manuel
Bermúdez-García,
‡a
Antonio Luis
Llamas-Saiz,
d
Ramón
Artiaga,
e
Jorge Jose
López-Beceiro,
e
María Antonia
Señarís-Rodríguez,
a
Manuel
Sánchez-Andújar
*a
and
Socorro
Castro-García
a
Abstract
We have been able to prepare two new lead halides with the formula DMAPbX3 (where DMA is dimethylammonium and X is Cl− or Br−), which display a 4H-hexagonal perovskite polytype, an unusual crystal structure in hybrid organic–inorganic perovskites. Both compounds experience a first-order phase transition, the chloride at ∼320 K and the bromide at ∼250 K, which involves two cooperative processes: an off-center shift of the lead cations and an order–disorder process of the DMA cations. Additionally, a sharp dielectric transition is associated with this structural transition in both hybrids. Both compounds are semiconductors with band gap values of 3.5 eV (X: Cl−) and 3.0 eV (X: Br−). Also, the LT-phase of the Br− compound displays a broad red light photoluminescence (PL) emission (620 nm) and PLE excitation with the maximum at a soft UV wavelength (360 nm). This broadband emission and large Stokes-shifted PL seem to be related to a self-trapped exciton mechanism. Therefore, the uncommon 4H-hexagonal perovskite is a promising crystal structure for understanding and designing new hybrid materials with broad photoluminescent emission and dielectric properties.
![Graphical abstract: Hybrid lead halide [(CH3)2NH2]PbX3 (X = Cl− and Br−) hexagonal perovskites with multiple functional properties](/en/Image/Get?imageInfo.ImageType=GA&imageInfo.ImageIdentifier.ManuscriptID=C9TC03543E&imageInfo.ImageIdentifier.Year=2019)
Please wait while we load your content...
