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As the field of perovskite emerges, doping presents an optimistic way to upgrade the functionalities of these materials and improve the photoluminescence quantum yield (PLQY). While doping is well‐explored in perovskites, it has received less attention in layered double perovskites (LDPs). Doping with lanthanides is particularly interesting for these wide bandgap materials because of their narrow and intense luminescence spectra. Here, the doping of (PEA)4NaInCl8 LDP (PEA = Phenylethylammonium) with Tb3+ and complex of Tb3+ with hexafluoroacetylacetonate (hfa) is studied, i.e., tetrakis β‐diketonate complex. In both cases, energy transfer from host to dopant leading to photoluminescence (PL) emission due to Tb3+ f‐f transitions is observed. However, in the case of Tb3+ doping, sensitization is not very efficient due to the nonideal alignment of energy levels of the host and resonance acceptor energy levels of Tb3+. Whereas, doping of (PEA)4NaInCl8 with Tb3+ in the form of hfa complex, provides a more ideal energetic environment for the efficient energy transfer from host to Tb3+ in the LDP matrix, resulting in a 20‐fold enhancement in the luminescence efficiency. The doping of Tb3+ and Tb3+ complex in LDP sets the foundation for a new approach for the synthesis of LDPs‐lanthanide host‐guest systems for high PLQY. [ABSTRACT FROM AUTHOR]

The high toxicity and instability of lead halide perovskites hamper their broad applications in optoelectronics and photocatalysis. Lead-free halide Cs2AgBiCl6 double perovskite is considered a potential candidate due to less toxicity and high stability. However, its relatively large band gap of 2.64 eV absorbs a very narrow range of the solar spectrum. Herein, we synthesized Cu-doped Cs2AgBiCl6 double perovskites using three different methods, namely a hydrothermal, a post synthetic grinding and an in situ mechanochemical grinding method. We show that the absorption band of Cs2AgBiCl6 is significantly extended into the NIR range by doping with transition metal Cu. The extended absorption tail up to ∼850 nm and broad absorption centred at around 950 nm are attributed to the formation of new sub band gap states and d–d transition of Cu doped in the lattice, respectively. This work provides an effective material that could possibly extend the optical response of lead-free double perovskites for optoelectronic devices. [ABSTRACT FROM AUTHOR]

The layered hybrid double perovskites emerged as excellent semiconductor materials owing to their environment compatibility and stability. However, these materials are weakly luminescent, and their photoluminescence (PL) properties can be modulated via doping. While Mn2+ doping in perovskites is well known, but to the best of our knowledge the doping of Mn2+ in layered double perovskites (LDPs) is yet to be explored. Herein, for the first time, we demonstrate the doping of Mn2+ in hybrid inorganic-organic two-dimensional (2D) LDPs, (BA)4AgBiBr8 (BAÂ =Â n-butyl amine) via a simple solid-state mechanochemical route. The powder x-ray diffraction pattern, and electron paramagnetic resonance analysis confirm the successful incorporation of Mn2+ ions inside (BA)4AgBiBr8 lattice. The Mn2+ doped 2D LDP shows energy transfer from host excitons to d-electrons of Mn2+ ions, which results in red-shifted broad Mn2+ emission band centered at 625 nm, attributed to the spin-forbidden 4T1 to 6A1 internal transition. This work opens up new possibilities to dope metal ions in 2D LDPs to tune the optical as well as magnetic properties. [ABSTRACT FROM AUTHOR]

The layered hybrid double perovskites emerged as excellent semiconductor materials owing to their environment compatibility and stability. However, these materials are weakly luminescent, and their photoluminescence (PL) properties can be modulated via doping. While Mn2+ doping in perovskites is well known, but to the best of our knowledge the doping of Mn2+ in layered double perovskites (LDPs) is yet to be explored. Herein, for the first time, we demonstrate the doping of Mn2+ in hybrid inorganic-organic two-dimensional (2D) LDPs, (BA)4AgBiBr8 (BAÂ =Â n-butyl amine) via a simple solid-state mechanochemical route. The powder x-ray diffraction pattern, and electron paramagnetic resonance analysis confirm the successful incorporation of Mn2+ ions inside (BA)4AgBiBr8 lattice. The Mn2+ doped 2D LDP shows energy transfer from host excitons to d-electrons of Mn2+ ions, which results in red-shifted broad Mn2+ emission band centered at 625 nm, attributed to the spin-forbidden 4T1 to 6A1 internal transition. This work opens up new possibilities to dope metal ions in 2D LDPs to tune the optical as well as magnetic properties. [ABSTRACT FROM AUTHOR]

Cobalt-based chalcogenides have emerged as fascinating materials for supercapacitor applications owing to the presence of various mixed valance oxidation states in their structure along with rich electrochemical properties. However, their limited stability and cyclic performance hinder their viability for practical use in supercapacitors. Herein, a facile hot injection colloidal route is demonstrated to design MoSe 2 -Co 9 S 8 nanoheterostructures (NHSs), which entails the epitaxial growth of Co 9 S 8 nanoparticles (NPs) over the basal planes of ultrathin MoSe 2 nanosheets (NSs). The interfacial engineering of the basal planes of MoSe 2 NSs with Co 9 S 8 NPs regulates the electronic properties and defects at the interfaces and increases the overall specific surface area and conductivity. As a result, MoSe 2 -Co 9 S 8 NHSs electrode unveils a substantially higher specific capacitance of 910.5 F g -1 at 1 A g -1 current density surpassing their individual counterparts. In addition, it demonstrates worthy solidity, retaining ≈90% of its capacitance and coulombic efficiency of 93.3% after 10,000 charge-discharge cycles at a high charge-discharge current density of 15 A g -1 . As a proof-of-concept, coin cells are fabricated using MoSe 2 -Co 9 S 8 NHSs which show 93% Coulomb efficiency and 86% capacitance retention. This study would pave the way for designing transition metal dichalcogenides (TMDs) - derived NHSs with superior capacitive properties., (© 2024 Wiley‐VCH GmbH.)

Mixed dimensional nanohybrids (MDNHs) between zero-dimensional (0D) perovskites and two-dimensional (2D) II-VI semiconductors hold great potential for photonic device applications. An in-depth study to understand the shuttling of charge carriers is carried out utilizing bifunctional ligands such as 4-aminothiophenol (4-ATP), p -aminobenzoic acid, and 6-amino-2-naphthoic acid in the synthesis of MDNHs of CsPbBr 3 nanocrystals (NCs) and CdSe/CdS/ZnS core/shell/shell (CSS) nanoplatelets (NPLs). These MDNHs form donor-bridge-acceptor systems, where the electronic interaction is greatly influenced by the nature of ligands. The smaller size and stronger binding affinity of 4-ATP to CSS NPLs lead to a faster rate of charge transfer as compared to other linkers. Electronic structure calculations under the framework of density functional theory (DFT) confirms that in 4-ATP capped CSS NPLs, stronger electronic overlap occurs between CSS NPLs and 4-ATP at the valence band maxima (VBM). Furthermore, Poisson distribution modeling proposes that in 4-ATP linked MDNHs, the number of CSS NPLs around CsPbBr 3 NCs is highest.