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In this communication, we report a new greenish-blue-emitting Cu(i) complex, Cu4Cl4(NP)2, a with high photoluminescence quantum yield of 90% and a short decay time of 9.9 μs. Due to the strong SOC combined with the small activation energy ΔEST, the emission at room temperature consists of approximately equivalent fast phosphorescence and TADF.

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Three thermally activated delayed fluorescence cationic cuprous complexes [Cu(POP) (ECAF)]PF (1, POP = bis(2-diphenylphosphinophenyl)ether, ECAF = 9,9-bis(9-ethylcarbazol-3-yl)-4,5-diazafluorene), [Cu(POP) (EHCAF)]PF (2, EHCAF = 9,9-bis(9-ethylhexylcarbazol-3-yl)-4,5-diazafluorene), and [Cu(POP) (PCAF)]PF (3, PCAF = 9,9-bis(9-phenylcarbazaol-3-yl)-4,5-diazafluorene) with bipolar 4,5-diazafluorene ligand substituted by bis-carbazole have been successfully prepared, and their UV absorption, photoluminescent properties, and electrochemical behaviors were investigated. At room temperature, complexes 1, 2, and 3 exhibit efficient yellowish-green emission with peak maxima of 550, 549, and 556 nm, respectively, and lifetimes of 5.7 μs. In powder states, the quantum yields (ϕ) of 22.4% for 1, 18.5% for 2, and 20.0% for 3, respectively, are found. These metal phosphors can be vacuum-evaporated and applied in the organic light-emitting diodes (OLEDs) of indium tin oxide/poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (40 nm)/4,4',4″-tri(9-carbazoyl)triphenylamine (15 nm)/cuprous complexes (10 wt %): 1,3-bis(9-carbazolyl)benzene (30 nm)/1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene (50 nm)/LiF (0.5 nm)/Al (100 nm). Complex 1-based device D1 achieved a maximum luminance of 11 010 cd m, a current efficiency of 47.03 cd A, and an external quantum efficiency of 14.81%. The high electroluminescence efficiencies of these complexes are assumed to be due to their good thermal stabilities and capture of both singlet and triplet excitons. The research presented here provides a powerful tool toward highly efficient and cheap OLED devices.

Herein, we present a new strategy in which highly emissive thermally activated delayed fluorescence (TADF) materials can be obtained from modifying or tuning a non-TADF donor (D)–acceptor (A)-type organic molecule via coordination of the metal ionic fragment. Theoretical calculation and photophysical properties reveal that the D–A-type free ligand emits both weak fluorescence and dual room-temperature phosphorescence, whereas the two Ag­(I) complexes display efficient blue TADF, exhibiting photoluminescence quantum yields nearly 100% in films with short decay lifetimes (τ ≈ 6 μs). This is attributed to the four optimized parameters induced by Ag­(I) coordination: (1) narrow singlet (S1)–triplet (T1) energy gaps (ΔE ST). (2) T1 states have a hybrid local excitation and charge transfer (CT) character, and S1 states have a predominant CT character. Both the parameters facilitate reverse intersystem crossing. (3) Radiative rate constant (k r(S1→S0)) is increased. (4) Molecular rigidity is strengthened. For the first time, this work shows a powerful method to design efficient ligand-centered TADF in Ag­(I) complexes based on the conventional D–A-type molecule, which significantly enriches the chemical space for the development of TADF materials.

Crystal structures of the AHL-lactonase AidH in complex with substrate and product are reported at high resolution and a catalytic mechanism is proposed for the metal-independent AHL-lactonase.

Three highly emissive binuclear Cu(i) complexes have been synthesized and used as emitting dopants in highly efficient organic light-emitting devices.

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 π-π* and π-π* states and thus trigger the ligand-localized phosphorescence ( π-π*).