Long-afterglow hybrid halide perovskites

Efficient Room-Temperature Phosphorescence in 2D Perovskite via Mixed Organic Cation Incorporation

The achievement of RTP in hybrid organic-inorganic perovskites (HIOPs) via molecular engineering remains relatively uncommon. Here, a series of novel 2D HIOPs composed of mixed organic cations such as naphthalene methylamine (NMA) and 2-(4-methylphenyl) ethanamine (4MPEA) are reported. Efficient RTP and tunable emissions ranging from green to yellow to orange, depending on the doping ratio, are activated in the organic cation-mixed 2D HIOPs system. It has been certified that the triplet excitons of NMA primarily stem from the Wannier excitons of the inorganic layer through an energy transfer process. By gradually altering the halide composition from Br to Cl, the NMA substituted chlorine-based 2D HIOPs show an outstandingly long lifetime of 176 ms. Moreover, potential applications in multiple information encryption and displays have been demonstrated. Our study confirms the effectiveness of strategically hybridizing organic cations with inorganic matrices at the molecular level to achieve high performance RTP.

Unlocking the Potential of Organic-Inorganic Hybrid Manganese Halides for Advanced Optoelectronic Applications

Organic-inorganic hybrid manganese(II) halides (OIMnHs) have garnered tremendous interest across a wide array of research fields owing to their outstanding optical properties, abundant structural diversity, low-cost solution processibility, and low toxicity, which make them extremely suitable for use as a new class of luminescent materials for various optoelectronic applications. Over the past years, a plethora of OIMnHs with different structural dimensionalities and multifunctionalities such as efficient photoluminescence (PL), radioluminescence, circularly polarized luminescence, and mechanoluminescence have been newly created by judicious screening of the organic cations and inorganic Mn(II) polyhedra. Specifically, through precise molecular and structural engineering, a series of OIMnHs with near-unity PL quantum yields, high anti-thermal quenching properties, and excellent stability in harsh conditions have been devised and explored for applications in light-emitting diodes (LEDs), X-ray scintillators, multimodal anti-counterfeiting, and fluorescent sensing. In this review, the latest advancements in the development of OIMnHs as efficient light-emitting materials are summarized, which covers from their fundamental physicochemical properties to advanced optoelectronic applications, with an emphasis on the structural and functionality design especially for LEDs and X-ray detection and imaging. Current challenges and future efforts to unlock the potentials of these promising materials are also envisioned.

Recent strategies for triplet-state emission regulation toward non-lead organic-inorganic metal halides

Organic-inorganic metal halides (OIMHs) have strengthened the development of triplet-state emission materials due to their excellent luminescence performance. Due to the inherent toxicity of lead (Pb) significantly limiting its further advancement, numerous studies have been conducted to regulate triplet-state emission of non-Pb OIMHs, and several feasible strategies have been proposed. However, most of the non-Pb OIMHs reported have a relatively short lifetime or a low luminescence efficiency, not in favor of their application. In this review, we provide a summary of recent reports on the regulation of triplet-state emissions in non-Pb OIMHs to provide benefits for the design of innovative luminescent materials. Our focus is primarily on exploring the internal and external factors that influence the triplet-state emission. Starting from the luminescence mechanism, the current strategies for regulating triplet-state emissions are summarized. Moreover, by manipulating these strategies, it becomes feasible to achieve triplet-state emissions that span a range of colors from blue to red, and even extend into the near-infrared spectrum with high luminescence efficiency, while also increasing their lifetimes. This review not only provides fresh insights into the advancement of triplet-state emissions in OIMHs but also integrates experimental and theoretical perspectives to illuminate the trajectory of future research endeavors.

Full-color, time-valve controllable and Janus-type long-persistent luminescence from all-inorganic halide perovskites

Long persistent luminescence (LPL) has gained considerable attention for the applications in decoration, emergency signage, information encryption and biomedicine. However, recently developed LPL materials - encompassing inorganics, organics and inorganic-organic hybrids - often display monochromatic afterglow with limited functionality. Furthermore, triplet exciton-based phosphors are prone to thermal quenching, significantly restricting their high emission efficiency. Here, we show a straightforward wet-chemistry approach for fabricating multimode LPL materials by introducing both anion (Br-) and cation (Sn2+) doping into hexagonal CsCdCl3 all-inorganic perovskites. This process involves establishing new trapping centers from [CdCl6-nBrn]4- and/or [Sn2-nCdnCl9]5- linker units, disrupting the local symmetry in the host framework. These halide perovskites demonstrate afterglow duration time ( > 2,000 s), nearly full-color coverage, high photoluminescence quantum yield ( ~ 84.47%), and the anti-thermal quenching temperature up to 377 K. Particularly, CsCdCl3:x%Br display temperature-dependent LPL and time-valve controllable time-dependent luminescence, while CsCdCl3:x%Sn exhibit forward and reverse excitation-dependent Janus-type luminescence. Combining both experimental and computational studies, this finding not only introduces a local-symmetry breaking strategy for simultaneously enhancing afterglow lifetime and efficiency, but also provides new insights into the multimode LPL materials with dynamic tunability for applications in luminescence, photonics, high-security anti-counterfeiting and information storage.

A time-multiplexed self-erasing nanopaper for water induced information transmission

The progressive presentation of multilevel information enhances the security level of information storage and transmission. Here, a time-multiplexed self-erasing nanopaper was developed by integrating cellulose nanofiber (CNF)-stabilized gold nanoclusters and CNF-modified long afterglow materials. The orange fluorescence of gold nanoclusters on nanopaper was regulated by the reversible swelling and shrinking of CNF induced by water solution, while the cyan fluorescence of micron-long afterglow remained stable and acted as the background signal. It was noteworthy that the fluorescence colour and intensity of the nanopaper could be freely adjusted between orange and cyan on the time scale. Therefore, the array information on the nanopaper could be encoded by a water solution, iterated variation as the step-by-step solvent volatilized on the time scale measured by the time of the afterglow duration. This work provides a new approach for constructing time-multiplexed self-erasing nanopaper for confidential information storage and transmission.