crown-6)] + (KC) cations are used for cocrystallization with manganese halides, producing isostructural single crystals of organic− inorganic hybrid complexes, [K(dibenzo-18-crown-6)] 2 MnX 4 (abbreviated (KC) 2 MnX 4 ) (X = Cl, Br), which feature one-dimensional morphology and green phosphorescence with considerable photoluminescence quantum yields accompanied by excellent optical waveguide behavior with a low loss coefficient. More interestingly, (KC) 2 MnX 4 crystallizes in the monoclinic space group Cc belonging to the achiral point group m (C s ), where the non-centrosymmetric arrangement of racemic units, with right-and left-handed rotating optical axes, endows these achiral single crystals with circularly polarized luminescence, observed for the first time.

Micro/nanoscale photonic barcodes based on multicolor luminescent segmented heterojunctions hold potential for applications in information security. However, such multicolor heterojunctions reported thus far are exclusively based on static luminescent signals, thus restricting their application in advanced confidential information protection. Reported here is a strategy to design responsive photonic barcodes with heterobimetallic (Tb3+/Eu3+) metal—organic framework multicolor heterostructures. The spatial colors could be precisely controlled by thermally manipulating the energy‐transfer process between the two lanthanides, thus achieving responsive covert photonic barcodes. Also demonstrated is that spatially resolved responsive barcodes with multi‐responsive features could be created in a single heterostructure. These findings offer unique opportunities to purposely design highly integrated responsive microstructures and smart devices toward advanced anti‐counterfeiting applications.

Organic-inorganic metal-halide materials (OIMMs) with zero-dimensional (0D) structures offer useful optical properties with a wide range of applications. However, successful examples of 0D structural OIMMs with well-defined optical performance at the micro-/nanometer scale are limited. We prepared one-dimensional (1D) (DTA) 2 SbCl 5 •DTAC (DTAC = dodecyl trimethyl ammonium chloride) single-crystal microrods and 2D microplates with a 0D structure in which individual (SbCl 5 ) 2À quadrangular units are completely isolated and surrounded by the organic cation DTA + . The organic molecular unit with a long alkyl chain (C 12 ) and three methyl groups enables microrod and -plate formation. The singlecrystal microrods/-plates exhibit a broadband orange emission peak at 610 nm with a photoluminescence quantum yield (PLQY) of ca. 90 % and a large Stokes shift of 260 nm under photoexcitation. The broad emission originates from selftrapping excitons. Spatially resolved PL spectra confirm that these microrods exhibit an optical waveguide effect with a low loss coefficient (0.0019 dB mm À1 ) during propagation, and linear polarized photoemission with a polarization contrast (0.57).Organic-inorganic metal-halide materials (OIMMs), a bulk crystal with 0D structure at the molecular level, have attracted tremendous attentions due to their potential optoelectronic applications as light-emitting materials. [1] These materials though in bulk; but can have bright emission and also retain as high as near unity photoluminescence quantum yield (PLQY). [2] Among different applications these could also serve as a potential optical materials in micro-/ nanosized optical waveguides. [3] To date, research on optical

Thermally activated delayed fluorescent (TADF) materials are promising to overcome triplet-induced optical loss in the pursuit of electrically pumped organic lasers. However, population inversion is difficult to establish in these materials due to the severe suppression of triplet-to-singlet upconversion in their condensed states. In this work, we report thermally activated lasing in solution-processed coassembled microcrystals, where TADF dyes were uniformly dispersed into crystalline matrices to ensure an efficient reverse intersystem crossing (RISC). The darkstate triplet excitons harvested by the RISC were effectively converted into radiative singlet excitons, which subsequently participated in the population inversion to boost lasing with an unusual temperature dependence. The lasing wavelength was tuned over the full visible spectrum by doping various TADF laser dyes, owing to the excellent compatibility. Trichromatic TADF microlasers were precisely patterned into periodic pixelated arrays by a template-confined solution-growth method. With as-prepared TADF microlaser arrays as display panels, vivid laser displays were achieved under programmable excitation. These results offer valuable enlightenment to minimize triplet state-related energy losses toward high-performance lasers.

Zero-dimensional (0D) copper-based metal halides have exhibited great potential as luminescent materials with structural tunability and impressive emission properties. Luminescence from highly ordered self-assembly of copper halides is typically characterized by high photoluminescence quantum efficiencies (PLQEs) and large Stokes shifts, which are the most attractive features for active optical waveguides. Here, we report a novel highly luminescent organic copper halide, (PTMA)3Cu3I6 (PTMA: phenyltrimethylammonium), in which individual face- and edge-sharing [Cu3I6]3– clusters are surrounded by PTMA+ organic molecules, forming a highly ordered 0D crystal structure at the molecular level. Upon photoexcitation, (PTMA)3Cu3I6 single crystals exhibit a broadband yellow emission with a high PLQE of up to 80.3%. Theoretical calculations revealed that the photogenerated electron–hole pairs in (PTMA)3Cu3I6 are spatially separated from each other, i.e., electrons are preferred to be localized in PTMA+ organic molecules, while holes are highly localized in the inorganic [Cu3I6]3– clusters; thus, the emission arises from the radiative recombination of ligand-to-metal charge transfer (LMCT). In addition, colloidal nanocrystals of (PTMA)3Cu3I6 were successfully prepared, which show similar luminescence properties with their single crystals. The high PLQE, negligible self-absorption as well as the highly ordered self-assembly of metal halide clusters make (PTMA)3Cu3I6 microplates promising materials for low-loss optical waveguides, exhibiting an optical loss coefficient of 0.0157 dB μm–1 and highly linear polarized luminescence with a polarization anisotropy of 1.78.

Metal-organic frameworks (MOFs) heterostructures with domain-controlled emissive colors have shown great potential for achieving high-throughput sensing, anti-counterfeit and information security.H ere,astrategy based on sterichindrance effect is proposed to construct lateral lanthanide-MOFs (Ln-MOFs) epitaxial heterostructures,where the channel-directed guest molecules are introduced to rebalance inplane and out-of-plane growth rates of the Ln-MOFs microrods and eventually generate lateral MOF epitaxial heterostructures with controllable aspect ratios.Alibrary of lateral Ln-MOFs heterostructures are acquired through as tepwise epitaxial growth procedure,from which rational modulation of each domain with specific lanthanide doping species allows for definition of photonic barcodes in at wo-dimensional (2D) domain with remarkably enlarged encoding capacity.T he results providem olecular-level insight into the use of modulators in governing crystallite morphology for spatially assembling multifunctional heterostructures.

This work reports the successful preparation of a new type of crystalline luminescent organic nanodot (<3.5 nm) by kinetically trapped self‐assembly, which is then used as a simplified π‐packing model to simulate the structure of CDs. The precise structure and J‐aggregation‐induced photoluminescence (PL) of the nanodots are revealed by investigating the structural relationship between the nanodots and the corresponding single crystals and their properties. Compared with the single crystals, crystalline organic nanodots show longer PL lifetime, higher PL quantum yield, and narrower PL peak, indicating that they are potential organic quantum nanodots. In addition, the efficient π‐stacking environment in the corresponding single crystals can promote π‐aggregation‐induced PL anisotropy. This work indicates crystalline organic nanodots with precise structures to be potentially useful for understanding the structures of CDs and to be attractive potential luminescent materials.

Metal‐organic frameworks (MOFs) have recently emerged as appealing platforms to construct microlasers owing to their compelling characters combining the excellent stability of inorganic materials and processable characters of organic materials. However, MOF microstructures developed thus far are generally composed of multiple edge boundaries due to their crystalline nature, which consequently raises significant scattering losses that are detrimental to lasing performance. In this work, we propose a strategy to overcome the above drawback by designing spherically shaped MOFs microcavities. Such spherical MOF microstructures are constructed by amorphizing MOFs with a topological distortion network through introducing flexible building blocks into the growth environment. With an ultra‐smooth surface and excellent circular boundaries, the acquired spherical microcavities possess a Q factor as high as ≈104 and can provide sufficient feedback for high‐quality single‐mode lasing oscillations. We hope that these results will pave an avenue for the construction of new types of flexible MOF‐based photonic components.