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Low-dimensional materials have attracted increasing attention due to their guiding significance for material preparation and potential wide-ranging applications. Through the controllable synthesis and suitably designed fusion of low-dimensional materials into ordered complex superstructures, it has become an effective way to explore new properties of materials and construct structures meeting new application needs. Based on low-dimensional materials such as metal oxides, copolymers, metal-organic complexes, and organic crystals, great efforts have been devoted to the design and construction of complex superstructures with regular repeatability. A series of unique cases including multi-block, core/multi-shell, hyperbranched and network structures have been reported, which has promoted the development of the field of material preparation. Herein, we summarize representative progress of low-dimensional complex superstructures in a reasonable structure classification manner. Ultimately, the existing challenges are discussed, and an outlook is given for future study of precise construction of superstructures as well as exploitation of potential applications.

Deep‐red and near‐infrared emitters with twisted donor–acceptor (D–A) structures often exhibit suboptimal performance in organic light‐emitting diodes (OLEDs) due to constraints imposed by the energy gap law. In this work, a pure hydrogen carbon (PHC) host material named SBF‐DTP is purposefully tailored for deep‐red OLEDs. The excellent capacity of SBF‐DTP to support D–A type DR emitters effectively arises from its distinctive attributes: localized excitation states, 3D configuration, and low polarity. When employing SBF‐DTP as the host for the fluorescence emitter DCPA‐TPA and the thermally activated delayed fluorescence emitter APDC‐DTPA, doped films exhibit substantially enhanced photoluminescence quantum yields. This improvement leads to high‐efficiency OLEDs with external quantum efficiencies of 5.47% for DCPA‐TPA and 20.03% for APDC‐DTPA, respectively, which is about twice as high as the initial reports. This findings underscore the paramount significance of developing efficient host materials in the pursuit of high‐performance deep red and even near‐infrared OLEDs. [ABSTRACT FROM AUTHOR]

Near‐infrared light‐emitting diodes (NIR LEDs) based on perovskite quantum dots (QDs) have produced external quantum efficiency (EQE) of ~15 %. However, these high‐performance NIR‐QLEDs suffer from immediate carrier quenching because of the accumulation of migratable ions at the surface of the QDs. These uncoordinated ions and carriers—if not bound to the nanocrystal surface—serve as centers for exciton quenching and device degradation. In this work, we overcome this issue and fabricate high‐performance NIR QLEDs by devising a ligand anchoring strategy, which entails dissolving the strong‐binding ligand (Guanidine Hydroiodide, GAI) in the mediate‐polar solvent. By employing the dye‐sensitized device structure (phosphorescent indicator), we demonstrate the elimination of the interface defects. The treated QDs films exhibit an exciton binding energy of 117 meV: this represents a 1.5‐fold increase compared to that of the control (74 meV). We report, as a result, the NIR QLEDs with an EQE of 21 % which is a record among NIR perovskite QLEDs. These QLEDs also exhibit a 7‐fold higher operational stability than that of the best previously reported NIR QLEDs. Furthermore, we demonstrate that the QDs are compatible with large‐area QLEDs: we showcase 900 mm2 QLEDs with EQE approaching 20 %. [ABSTRACT FROM AUTHOR]

Noncovalent spatial interaction has become an intriguing and important tool for constructing optoelectronic molecules. In this study, we linearly attached three conjugated units in a multi π‐stacked manner by using just one trident bridge based on indeno[2,1‐b]fluorene. To achieve this structure, we improved the synthetic approach through double C−H activation, significantly simplifying the preparation process. Due to the proximity of the C10, C11, and C12 sites in indeno[2,1‐b]fluorene, we derived two novel donor|acceptor|donor (D|A|D) type molecules, 2DMB and 2DMFB, which exhibited closely packed intramolecular stacking, enabling efficient through‐space charge transfer. This molecular construction is particularly suitable for developing high‐performance thermally activated delayed fluorescence materials. With donor(s) and acceptor(s) constrained and separated within this spatially rigid structure, elevated radiative transition rates, and high photoluminescence quantum yields were achieved. Organic light‐emitting diodes incorporating 2DMB and 2DMFB demonstrated superior efficiency, achieving maximum external quantum efficiencies of 28.6 % and 16.2 %, respectively. [ABSTRACT FROM AUTHOR]

Lanthanide ions doped in perovskite (LIDP) nanocrystals (NCs) provide an effective way to utilize the emission of lanthanide metals in a solution‐processable way, combining the theoretical photoluminance quantum yield (PLQY) of ≈200%. To utilize advantages, LIDP‐NCs have inspired studies exploring the fundamental physics of energy transfer, including the up‐conversion or down‐conversion process, and the optoelectronic applications of solar cells and white light‐emitting didoes. This review broadens the scope of LIDP nanocrystal matrix semiconductors in electroluminescence devices in the near‐infrared (NIR) range (>900 nm). A research is summarized on the synergistic effect of lanthanide ions and perovskite matrix in the near‐infrared region, and discuss from the perspective of fabrication of lanthanide‐based electroluminescent devices using perovskite materials as the matrix. The multiple optical transitions, bandgap tunability, and quantum‐cutting effect to provide a tutorial on understanding LIDP‐NCs are started. The details of synthesizing LIDP materials and aim to lay the foundation for preparing NIR electroluminescent devices with high efficiency and application value are then illustrated. The scientific issues that limit the performance of LIDP NCs‐based electroluminescent devices and discuss the potential strategies for the future development of LIDP material are focused on. [ABSTRACT FROM AUTHOR]

In the realm of organic light‐emitting diode (OLED), through‐space charge transfer (TSCT) thermally activated delayed fluorescence (TADF) emitters have demonstrated remarkable achievements. Nevertheless, realizing both deep‐blue emission and high efficiency by the TSCT strategy remains a persistent challenge. Here, the novel donor‐π‐donor‐σ‐acceptor (D‐π‐D‐σ‐A) type deep‐blue TSCT emitter, namely D‐tCz‐BO, is formulated to investigate its performance in OLED. D‐tCz‐BO show a narrow deep‐blue emission and efficient TADF character (λPL = 448, FWHM = 54 nm, ΦPL = 82%, and ΔEST = 0.09 eV). More importantly, the OLED based on D‐tCz‐BO as the emitter showed a maximum external quantum efficiency (EQEmax) of 20.5%, with a Commission Internationale de l'Eclairage (CIE) coordinate of (0.14, 0.12). This represents one of the best deep‐blue TSCT‐TADF emitters to date. [ABSTRACT FROM AUTHOR]