Warm-White-Light Perdeuterated Dy(III) Complex with a Photoluminescence Quantum Yield of up to 72% in Deuterated Chloroform.

Herein, a deuteration strategy is proposed to enhance the photoluminescence quantum yield (PLQY) of a Dy(III) complex. The perdeuterated Dy(III) complex Dy(D-DPPOP)3 (D-DPPOP = 6-[bis(phenyl-d5)phosphoryl]picolinate-d3) exhibits a high PLQY of up to 72% in deuterated chloroform, which is 4.8 times higher than that of the nondeuterated Dy(III) complex Dy(DPPOP)3. Then the corresponding ultraviolet-excited light-emitting diode is fabricated, showing a warm-white light with a Commission Internationale de l'Eclairage (CIE) of (0.36, 0.41) and a color temperature of around 4800 K. The deuteration strategy to improve the PLQY of the Dy(III) complex is proved in this work, and it will inspire the further design of white-emission Dy(III) complexes with high efficiency.

Complexes of Ce(III) and Bis(pyrazolyl)borate Ligands: Synthesis, Structures, and Luminescence Properties.

Luminescent cerium(III) complexes based on the d-f transition have characteristics of broad emission spectra, tunable emission colors, and short excited state lifetimes, showing potential applications in display, lighting, and other fields. Thus it is important to construct luminescent Ce(III) complexes with high photoluminescence efficiency and good stability. In this work, five Ce(III) complexes with dihydrobis(pyrazolyl)borate or diphenylbis(pyrazolyl)borate ligands, where pyrazolyl stands for pyrazolyl, 3-methylpyrazolyl, or 3,5-dimethylpyrazolyl, were designed and synthesized, showing emission colors from deep blue to yellow with a maximum wavelength in the range of 390-560 nm, short excited state lifetimes of 30-80 ns, and photoluminescence quantum yields exceeding 75% in solid powder. By comparing these complexes, it is found that higher photoluminescence efficiency and better thermal/air stability could be achieved in the complexes with dihydrobis(pyrazolyl)borate ligands.

Deep-blue emitting cerium(III) complexes with tris(pyrazolyl)borate and triflate ligands.

Red, green and blue emitting materials, the three primary colors, are very important in lighting and display. Red-emitting Eu(III) complexes and green-emitting Tb(III) complexes exhibit high color purity and photoluminescence (PL) efficiency. However, it is difficult to realize efficient blue emission based on f-f transition. Alternatively, Ce3+ with d-f transition can be used to construct blue-emitting lanthanide complexes. Herein, we synthesized two heteroleptic Ce(III) complexes Ce-1Me-OTf and Ce-2Me-OTf based on hydrotris(3-methylpyrazolyl)borate (TpMe) and hydrotris(3,5-dimethylpyrazolyl)borate (TpMe2) ligands, respectively, in which triflate is used as the ancillary ligand. Ce-1Me-OTf and Ce-2Me-OTf exhibit strong blue emission in dichloromethane and as powder with maximum emission wavelengths in the range of 424-436 nm. Both complexes demonstrate near-unity photoluminescence quantum yields (PLQYs) in powder and good sublimation properties. In particular, Ce-1Me-OTf emits deep blue light both in dichloromethane and as powder with Commission Internationale de l'Eclairage (CIE) coordinates of (0.15, 0.07) and (0.15, 0.06), respectively, which are close to the standard blue points recommended by the National Television System Committee (NTSC) and the European Broadcast Union (EBU).

Mechanochromic properties in a mononuclear Cu(I) complex without cuprophilic interactions.

Two polymorphs of Cu[(3,4-bis(diphenylphosphino)thiophene)(bis(pyrazol-1-yl)borohydrate)] (1) were isolated. The blue luminescent crystals have evident mechanochromic luminescent (MCL) properties. Based on photophysical and structural analysis, the pore structure in the blue crystals is considered to be the main reason for the MCL properties.

A Family of Highly Emissive Lanthanide Complexes Constructed with 6-(Diphenylphosphoryl)picolinate.

We report a novel family of lanthanide complexes Ln(DPPOP)3 (Ln = Pr, Nd, Sm, Eu, Tb, Dy, Er, and Yb) employing anionic tridentate (O∧N∧O) ligand 6-(diphenylphosphoryl)picolinate (DPPOP). Crystal structures of the complexes reveal that each lanthanide ion is nine-coordinated by three tridentate ligands. In the crystals, 1D channels are found, which can absorb and eliminate water reversibly. DPPOP possesses high triplet energy and can sensitize a series of lanthanide ions. An energy transfer mechanism is proposed through the higher excited states of the lanthanide ions. In the solid state, remarkably high quantum yields in the visible range are obtained: 81% for Eu(III), 97% for Tb(III), 13% for Dy(III), and 4% for Sm(III) complex.

Self-Repairing Tin-Based Perovskite Solar Cells with a Breakthrough Efficiency Over 11.

The development of tin (Sn)-based perovskite solar cells (PSCs) is hindered by their lower power conversion efficiency and poorer stability compared to the lead-based ones, which arise from the easy oxidation of Sn2+ to Sn4+ . Herein, phenylhydrazine hydrochloride (PHCl) is introduced into FASnI3 (FA = NH2 CH  NH2 + ) perovskite films to reduce the existing Sn4+ and prevent the further degradation of FASnI3 , since PHCl has a reductive hydrazino group and a hydrophobic phenyl group. Consequently, the device achieves a record power conversion efficiency of 11.4% for lead-free PSCs. Besides, the unencapsulated device displays almost no efficiency reduction in a glove box over 110 days and shows efficiency recovery after being exposed to air, due to a proposed self-repairing trap state passivation process.

Correction: Highly efficient room-temperature phosphorescence achieved by gadolinium complexes.

Correction for 'Highly efficient room-temperature phosphorescence achieved by gadolinium complexes' by Boxun Sun et al., Dalton Trans., 2019, 48, 14958-14961.

Highly efficient room-temperature phosphorescence achieved by gadolinium complexes.

A new family of room temperature phosphorescent materials with emission lifetimes in microseconds has been reported in this work. Phosphorescence of gadolinium complexes with emission color from blue to orange has been obtained at room temperature with a maximum photoluminescence quantum yield of 66%, benefiting from appropriate molecular structures and favorable encapsulation methods.

Quantum Yields over 80% Achieved in Luminescent Europium Complexes by Employing Diphenylphosphoryl Tridentate Ligands.

Four tridentate europium(III) complexes containing a diphenylphosphoryl group are prepared with strong bonding between the ligands and centered ion, convinced by crystal structures. Compared to their parent bidentate complexes, the tridentate complexes display improved and exceptionally high photoluminescence quantum yields (PLQYs) in powder (all over 80%, best 91%), as well as in a CH2Cl2 solution and poly(methyl methacrylate) films, benefiting from compact, stable, and saturated coordination.

Water-Soluble and Highly Luminescent Europium(III) Complexes with Favorable Photostability and Sensitive pH Response Behavior.

Two highly luminescent and water-soluble Eu(III) complexes, Eu1 and Eu2, based on novel carboxyl-functionalized 1,5-naphthyridine derivatives 8-hydroxy-1,5-naphthyridine-2-carboxylic acid (H2L1) and 7-cyano-8-hydroxy-1,5-naphthyridine-2-carboxylic acid (H2L2), respectively, are designed and synthesized. The crystal structure of Eu2 indicates that the central Eu(III) ion is nine-coordinated by three tridentate ligands (O^N^O). Both Eu1 and Eu2 show strong luminescence in aqueous solution with quantum yields (lifetimes) of 28% (1.1 ms) and 14% (0.76 ms), respectively. The chelates display unique UV-light stability in solution and remain highly emissive after 100 min of strong UV irradiation (∼300 W·m-2 at 345 nm). Moreover, they exhibit reversible luminescence intensity changes with varied pH values, and the response mechanism is investigated. "Turn-on" of the Eu(III) emission upon increasing pH is realized by ligand structure change from keto to enol anion form, resulting in red-shifted absorption band and suppressed quenching from solvents and N-H vibration upon deprotonating. The results show that these novel Eu(III) complexes are quite intriguing for potential application as bioimaging agents and pH probes.