Low-dimensional halide perovskites easily suffer from the structural distortion related to significant quantum confinement effects. Organic tin bromide perovskite C4N2H14SnBr4 is a unique one-dimensional (1D) structure in which the edge sharing octahedral tin bromide chains [SnBr4 2–]∞ are embraced by the organic cations C4N2H14 2+ to form the bulk assembly of core–shell quantum wires. Some unusual phenomena under high pressure are accordingly expected. Here, an intriguing pressure-induced emission (PIE) in C4N2H14SnBr4 was successfully achieved by means of a diamond anvil cell. The observed PIE is greatly associated with the large distortion of [SnBr6]4– octahedral motifs resulting from a structural phase transition, which can be corroborated by in situ high-pressure photoluminescence, absorption, and angle-dispersive X-ray diffraction spectra. The distorted [SnBr6]4– octahedra would accordingly facilitate the radiative recombination of self-trapped excitons (STEs) by lifting the activation energy of detrapping of self-trapped states. First-principles calculations indicate that the enhanced transition dipole moment and the increased binding energy of STEs are highly responsible for the remarkable PIE. This work will improve the potential applications in the fields of pressure sensors, trademark security, and information storage.
Maximizing the regeneration of singlet excitons remains a considerable challenge in deep-blue emission systems to obtain low-cost, high-efficiency fluorescent materials. However, the formation of the long-lifetime triplet excitons generally dominates the radiative process, making it greatly difficult to harvest deep-blue emission with high color purity because of the depression of singlet excitons. Here, a very bright deep-blue emission in double perovskite Cs2Na0.4Ag0.6InCl6 alloyed with Bi doping (CNAICB) was successfully achieved by pressure-driven reverse intersystem crossing (RISC), an abnormal photophysical process of energy transfer from the excited triplet state back to the singlet. Therein, the inherently broad emission of CNAICB was associated with the self-trapped excitons (STEs) at excited triplet states, whereas the radiative recombination of STEs populated in excited singlet states was responsible for the observed deep-blue emission. Moreover, the deep-blue emission corresponds to Commission Internationale de L’Eclairage (CIE) coordinates (0.16, 0.06) at 5.01 GPa, which meets the requirement of Rec. 2020 display standards. Likewise, pressure was introduced as an efficient tool to rule out the possibility of the recombination of free excitons and clarify the long-standing conventional dispute over the origin of the low-wavelength emission of Cs2AgInCl6. Our study not only demonstrates that pressure can be a robust means to boost the deep-blue emission but also provides deep insights into the structure–property relationship of lead-free CNAICB double perovskites.
Metal-halide perovskites (MHPs) have attracted tremendous attention because of their excellent performance in photovoltaic devices, such as solar cells. However, because of the crucial relationship between emission intensity and performance, pressure-quenching of optical emission greatly restrict the potential application of MHPs. Here, we reported the unique pressure-induced emission enhancement (PIEE) of CsPb x Mn 1−x Cl 3 NCs. Different from other PIEE phenomena, the PIEE of CsPb x Mn 1−x Cl 3 NCs was caused by the enhancement of energy release from 4 T 1 to 6 A 1 of the Mn, attributed to the pressure-induced isostructural phase transition. Meanwhile, the photoluminescence (PL) can exist until almost 20 GPa, suggesting that CsPb x Mn 1−x Cl 3 NCs exhibited better environmental suitability and worked under high pressure. Our studies explored the relationship between bandgap microstructure and optical properties of CsPb x Mn 1−x Cl 3 NCs at high pressure and also gave insights into the optimization of photovoltaic performance, which promoting the design of functional MHPs.
The origin of green emission in the zero-dimensional (0D) perovskite Cs 4 PbBr 6 nanocrystals (NCs) remains a considerable debate. Herein, an approach involving a combination of high-pressure experiments and theoretical simulation was employed to elucidate the controversial origin of photoluminescence from emissive Cs 4 PbBr 6 NCs (E416). Results obtained from first-principles density functional theory (DFT) calculations, as implemented in the Vienna ab initio simulation package codes, implied that the photoluminescence energies from bromine vacancy decreased persistently with pressure. Experimentally, the photoluminescence energies tended to decrease in the low-pressure region, followed by an increase beyond ∼1.4 GPa. While the emergent disagreement between the first-principles calculation and highpressure experiment excludes the possibility of vacancy-tuning, the consistent change observed in the pressure-dependent emission between E416 and CsPbBr 3 NCs offered a reliable interpretation for the occurrence of green emission from a CsPbBr 3 impurity embedded in the Cs 4 PbBr 6 matrix. Further comprehensive analysis demonstrated that the strong green emission of E416 NCs originated from the impurity CsPbBr 3 NCs embedded in Cs 4 PbBr 6 matrix. Our study represents a significant step forward to a deeper understanding of the emissive origins of Cs 4 PbBr 6 NCs and promotes the application of this novel strategy in light-emitting devices.
Pressure‐induced emission (PIE) is extensively studied in halide perovskites or derivative hybrid halides. However, owing to the soft inorganic lattice of these materials, the intense emission is barely retained under ambient conditions, thus largely limiting their practical applications in optoelectronics at atmospheric pressure. Here, remarkably enhanced emission in microtubules of the 0D hybrid halide (C5H7N2)2ZnBr4 ((4AMP)2ZnBr4) is successfully achieved by means of pressure treatment at room temperature. Notably, the emission, which is over ten times more intense than the emission in the initial state, is retained under ambient conditions upon the complete release of pressure. Furthermore, the pressure processing enables the tuning of “sky blue light” before compression to “cool daylight” with a remarkable quantum yield of 88.52% after decompression, which is of considerable interest for applications in next‐generation lighting and displays. The irreversible electronic structural transition, induced by the steric hindrance with respect to complexly configurational organic molecules [4AMP], is highly responsible for the eventual retention of PIE and tuning of the color temperature. The findings represent a significant step toward the capture of PIE under ambient conditions, thus facilitating its potential solid‐state lighting applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.