Two efficient blue thermally activated delayed fluorescence compounds, B‐oCz and B‐oTC, composed of ortho‐donor (D)–acceptor (A) arrangement were designed and synthesized. The significant ...intramolecular D–A interactions induce a combined charge transfer pathway and thus achieve small ΔEST and high efficiencies. The concentration quenching can be effectively inhibited in films of these compounds. The blue non‐doped organic light emitting diodes (OLEDs) based on B‐oTC prepared from solution processes shows record‐high external quantum efficiency (EQE) of 19.1 %.
Blue note: Highly efficient blue thermally activated delayed fluorescent (TADF) materials have been developed by using a new design strategy. Solution‐processed, non‐doped blue organic light‐emitting diodes based on these emitters realized record‐high external quantum efficiency of 19.1 %.
Aqueous zinc-ion batteries (AZIBs) have garnered significant attention for large-scale applications due to their low cost, safety, and eco-friendliness. Among all cathode materials, Prussian blue and ...its analogues (PBAs) have garnered significant attention and been subjected to extensive research due to their diverse property-effectiveness, simple synthesis process, reversible Zn
2+
insertion/removal capability, and other notable characteristics. However, numerous studies have revealed that the utilization of PBAs as a cathode material in AZIBs still presents certain challenges, including limited energy density and prolonged structural instability during cycling. In light of the aforementioned opportunities and challenges for PBAs, we conducted a comprehensive literature review encompassing synthesis, analysis of energy storage mechanisms, enhancement of electrolyte-electrode interfaces, and battery applications. The objective of this review is to encourage active engagement from researchers interested in AZIBs and PBA cathode materials, thereby fostering research and industrialization efforts that collectively contribute towards the advancement of safe and environmentally friendly energy storage.
We review the synthesis of Prussian blue and its analogues, as well as the energy storage mechanism and the impact of electrolyte on the electrode, to encourage active engagement from researchers interested in AZIBs and PBA cathode materials with the aim of advancing clean and safe energy storage.
Covalent organic frameworks (COFs), a fast-growing field in crystalline porous materials, have achieved tremendous success in structure development and application exploration over the past decade. ...The vast majority of COFs reported to date are designed according to the basic concept of reticular chemistry, which is rooted in the idea that building blocks are fully connected within the frameworks. We demonstrate here that sub-stoichiometric construction of 2D/3D COFs can be accomplished by the condensation of a hexagonal linker with 4-connected building units. It is worth noting that the partially connected frameworks were successfully reticulated for 3D COFs for the first time, representing the highest BET surface area among imine-linked 3D COFs to data. The unreacted benzaldehydes in COF frameworks can enhance C2H2 and CO2 adsorption capacity and selectivities between C2H2/CH4 and C2H2/CO2 for sub-stoichiometric 2D COFs, while the reserved benzaldehydes control the interpenetrated architectures for the 3D case, achieving a rare non-interpenetrated pts topology for 3D COFs. This work not only paves a new avenue to build new COFs and endows residual function groups with further applications but also prompts redetermination of reticular frameworks in highly connected and symmetrical COFs.
Using a wet chemical process, a continuous network of silver nanowires was buried at the surface of a transparent polymer (PVA) to form a flexible transparent conductor, which shows high optical ...transparency, low sheet resistance, a smooth surface, and superior mechanical, thermal and chemical stabilities. The composite is a competitive choice for transparent electrodes in OLED and thin film solar cells.
Developing novel lead-free perovskite materials with suitable bandgaps and superior thermal stability is crucial to boost their applications in next-generation photovoltaic technologies. High ...throughput screening combined with the first principles method can accurately and effectively screen out promising perovskites. Herein, we select two lead-free all-inorganic halide double perovskite materials Cs2KMI6 (M = Ga, In) from 1026 compounds with the criteria including appropriate structure factors, positive decomposition energies, and suitable direct bandgaps. We investigated the thermal and mechanical stability, geometric and electronic structures, photoelectric properties, and defect formation energies for both perovskites Cs2KMI6 (M = Ga, In). They can exhibit excellent structural formability and stability through the analysis of structure factors, elastic constants, and stable chemical potential regions. In addition, we investigate the defect effects of Cs2KMI6 (M = Ga, In) on the photovoltaic performance by evaluating the defect formation energies and transition energy levels. Based on the HSE06 functional, we calculated the energy band structures of these two compounds and demonstrate the direct bandgaps of 1.69 eV (HSE06) and 2.16 eV (HSE06) for Cs2KGaI6 and Cs2KInI6, respectively. Moreover, we predicted excellent spectroscopic limited maximum efficiencies (SLMEs) of these two perovskites with high light absorption coefficients (around 105 cm−1), for instance, the SLME of Cs2KGaI6 can reach as high as 28.39%.
A sextuple ordered interpenetrated copper-naphthalenediimide network has been constructed by combining the features of porous metal-organic frameworks and π-conjugated supramolecular aggregation. The ...material exhibits intrinsic semiconductive features with narrow bandgap energy (1.2 eV) and outstanding electron transport. Theoretical calculations combined with experiments indicate that the high electron conduction may originate from π-d coupling and J-aggregation.
A novel sextuple interpenetrated copper-naphthalenediimide network based on adamantane-like cages has been constructed and demonstrates outstanding electron transport.
Thermally activated delayed fluorescence (TADF) materials that exhibit simultaneously high photoluminescence quantum yield (PLQY), rapid reverse intersystem crossing (RISC), and a high horizontal ...transition dipole ratio are highly desirable for realizing high‐performance organic light‐emitting diodes (OLEDs). However, achieving this goal remains a formidable challenge due to the stringent molecular design principles involved. Herein, three highly efficient TADF materials based on lactam‐type electron‐acceptors are reported. The inherent rigidity and planar structure of lactam units, along with the ordered molecular arrangement in solid states, contribute to the reduction of nonradiative decay and the high horizontal transition dipole ratio in the optimized TADF emitters. Moreover, through precise control of the alignment of the lowest excited states by adjusting the charge transfer strength, the rate constants for reverse intersystem crossing (kRISC) are dramatically boosted. Consequently, the two optimized emitters exhibit outstanding merits of ultra‐high PLQYs (98% and 99%), high horizontal transition dipole ratios (91% and 87%), and fast RISC (kRISC ≈ 1.7 × 106 s−1). Thanks to these merits, the doped OLEDs achieve excellent performance. The top‐performing device achieve a maximum external quantum efficiency of 34.3%, a peak luminance of 57376 cd m−2, and small efficiency roll‐off.
Novel lactam electron‐acceptors are utilized to construct high‐performance TADF molecules. The rigid molecular skeletons, ordered molecular arrangements, and precise control of excited states contribute to achieving ultra‐high PLQYs (98%−99%), high horizontal dipole ratios (87%−91%), and rapid RISC (kRISC ≈ 1.7 × 106 s−1) simultaneously. The optimized OLEDs attain high EQEs of up to 34.3%, accompanied by ultra‐high luminances and small efficiency roll‐offs.
An unusual room-temperature light sensitivity was realized in a polyoxometalate-based hybrid material due to cooperative multicomponent molecular charge-transfer interactions taking place in this ...material, mainly among POMs, NDIs, and other molecules. The functional π-acidic NDI linkers and POM clusters in the discussed hybrid material were individually designed as photosensors and electron reservoirs. To propose a photo-induced charge-transfer mechanism, EPR, XPS, UV-Vis and computational studies were carried out, and indicated the presence of active charge-transfer interactions among several of the components.
Room‐temperature phosphorescence (RTP) was realized for the first time in a polyoxometalate‐based charge‐transfer (CT) hybrid material bearing polyoxometalates (POMs) as electron‐donors (D) and rigid ...naphthalene diimides (NDIs) as electron‐acceptors (A), meanwhile, this hybrid material displayed photochromism as well. The significant D‐A anion–π interaction induced an additional through‐space charge‐transfer pathway. The resulting suitable D‐A CT states can efficiently bridge the relatively large energy gap between the NDI‐localized 1π–π* and 3π–π* states and thus trigger the ligand‐localized phosphorescence (3π–π*).
A unique polyoxometalate‐based charge‐transfer complex displays both photochromism and room‐temperature phosphorescence in ambient conditions, which are mainly attributable to the charge transfer behaviors induced by unorthodox anion–π interactions. The strategy of introducing intermolecular charge‐transfer states may open up new opportunities for developing efficient organic–inorganic hybrid photofunctional materials.
Peroxyoxalate chemiluminescence (PO-CL) is one of the most popular cold light sources, yet the drawback of aggregation-caused quenching limits their use. Here, we report a new kind of efficient ...bifunctional emitter derived from salicylic acid, which not only exhibits typical aggregation-induced emission (AIE) character but also has the ability to catalyze the CL process under basic conditions based on base sensitivity. By taking advantage of these unique features, we successfully confine the CL process on the surface of solid bases and provide a high-contrast visualization of CL emission. This method allows most of the common basic salts like sodium carbonate to be invisible encryption information ink and PO-CL solution to be a decryption tool to visualize the hidden information. The current study opens up an appealing way for the development of multifunction CL emitters for information encryption and decryption applications.
