Mixed-halide perovskites show tunable emission wavelength across the visible-light range, with optimum control of the light color. However, color stability remains limited due to the notorious halide segregation under illumination or an electric field. Here, a versatile path toward high-quality mixed-halide perovskites with high emission properties and resistance to halide segregation is presented. Through systematic in and ex situ characterizations, key features for this advancement are proposed: a slowed and controllable crystallization process can promote achievement of halide homogeneity, which in turn ensures thermodynamic stability; meanwhile, downsizing perovskite nanoparticle to nanometer-scale dimensions can enhance their resistance to external stimuli, strengthening the phase stability. Leveraging this strategy, devices are developed based on CsPbCl Br perovskite that achieves a champion external quantum efficiency (EQE) of 9.8% at 464 nm, making it one of the most efficient deep-blue mixed-halide perovskite light-emitting diodes (PeLEDs) to date. Particularly, the device demonstrates excellent spectral stability, maintaining a constant emission profile and position for over 60 min of continuous operation. The versatility of this approach with CsPbBr I PeLEDs is further showcased, achieving an impressive EQE of 12.7% at 576 nm.
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http://dx.doi.org/10.1002/adma.202304094 | DOI Listing |
Small
January 2025
Faculty of Physics and Astronomy, Adam Mickiewicz University, Poznan, 61-614, Poland.
The behavior of triple-cation mixed halide perovskite solar cells (PSCs) under ultrashort laser pulse irradiation at varying fluences is investigated, with a focus on local heating effects observed in femtosecond transient absorption (TA) studies. The carrier cooling time constant is found to increase from 230 fs at 2 µJ cm⁻ to 1.3 ps at 2 mJ cm⁻ while the charge population decay accelerates from tens of nanoseconds to the picosecond range within the same fluence range.
View Article and Find Full Text PDFDiscov Nano
January 2025
Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049, Madrid, Spain.
Chemically tuned organic-inorganic hybrid halide perovskites based on bromide and chloride anions CH(NH)Pb(BrCl) (CH(NH): formamidinium ion, FA) have been crystallized and investigated by neutron powder diffraction (NPD), single crystal X-ray diffraction (SCXRD), scanning electron microscopy (SEM) and UV-vis spectroscopy. FAPbBr and FAPbCl experience successive phase transitions upon cooling, lowering the symmetry from cubic to orthorhombic phases; however, these transitions are not observed for the mixed halide phases, probably due to compositional disorder. The band-gap engineering brought about by the chemical doping of FAPb (BrCl) perovskites (x = 0.
View Article and Find Full Text PDFSmall
January 2025
Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Vassilika Vouton, Heraklion, 70013, Greece.
Metal halide perovskites (MHPs) have attracted significant attention owing to their simple manufacturing process and unique optoelectronic properties. Their reversible electrical or optical property changes in response to oxidizing or reducing environments make them prospective materials for gas detection technologies. Despite advancements in perovskite-based sensor research, the mechanisms behind perovskite-gas interactions, vital for sensor performance, are still inconclusive.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Chemistry, City University of Hong Kong, Kowloon, 999077, Hong Kong.
Perovskite/silicon tandem solar cells (TSCs) are promising candidates for commercialization due to their outstanding power conversion efficiencies (PCEs). However, controlling the crystallization process and alleviating the phases/composition inhomogeneity represent a considerable challenge for perovskite layers grown on rough silicon substrates, ultimately limiting the efficiency and stability of TSC. Here, this study reports a "halide locking" strategy that simultaneously modulates the nucleation and crystal growth process of wide bandgap perovskites by introducing a multifunctional ammonium salt, thioacetylacetamide hydrochloride (TAACl), to bind with all types of cations and anions in the mixed halide perovskite precursor.
View Article and Find Full Text PDFNano Lett
January 2025
Departments of Chemistry, and Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States.
A-site cations in ABX metal halide perovskites do not contribute to the frontier electronic states. They influence optoelectronic properties indirectly through interaction with the BX sublattice. By systematically investigating correlated motions of Cs cations and the PbX lattice (X = Cl, Br, I), we demonstrate that the interaction between the two subsystems depends on electronegativity and size of the X-site anion.
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