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Using the chiral [Sm(tta)3(d-phen)] as emitter, the first example of chiral organo-Ln3+-based CP-WOLED with both attractive white-light efficiencies (ηMaxEQE = 1.55% and ηMaxCE = 1.61 cd A−1) and high dissymmetry factor (|gEL|Max = 0.011) is reported.

Upon the usage of Ba/Al instead of LiF/Al, [Ir(iqbt)(btp)(pbi)] exhibited an attractive ηMaxEQE of 4.24% for its reliable all-solution-processed NIR-PLEDs.

High-efficiency white light emission has been achieved for tetraphenylethylene-based Eu3+-metallopolymers, which also exhibited great potential for applications in ratiomeric temperature sensing and white light emitting diodes.

The copolymerization between 4-VP-PHI, MMA and the Eu3+-complex results in white light emitting Eu3+-metallopolymer, which not only has a lower detection limit, but also a more remarkable color change compared to 4-VP-PHI for the sensing of Zn2+.

All-solution-processed multilayered white polymer light-emitting diodes (WPLEDs) are promising candidates for low-cost and large-area flexible full-color flat-panel displays and solid-state lightin...

Using conventional fac-[Ir(C^N)3]-homoleptic or [Ir(C^N)2(L^X)]-bis-heteroleptic iridium(III)-complexes with NIR-phosphorescence (NIR = near infrared) as dopants, the realization of reliable NIR-OLEDs/PLEDs (organic/polymer light-emitting diodes) with high performance remains a real challenge. In this study, taking Hqibt (1-(benzo[b]-thiophen-2-yl)-isoquinoline) as the HC^N1 ligand, Hppy (phenyl-4-yl)pyridine) as the HC^N2 ligand and Br-Hpic (5-Br-picolinic acid) or Hpic (picolinic acid) as the N^O-ancillary, two novel C1-symmetric [Ir(C^N1)(C^N2)(N^O)]-tris-heteroleptic iridium(III)-complexes [Ir(iqbt)(ppy)(pic)] (1) and [Ir(iqbt)(ppy)(Br-pic)] (2) are molecularly designed, respectively, where large TDM (transition dipole moment) and strengthened 3MLCT (metal-to-ligand charge transfer) effects are established to afford their good NIR-phosphorescent efficiency (ΦPL = 0.27 for 1 (λem = 698 nm); 0.21 for 2 (λem = 696 nm)). Moreover, in their doped EMLs (emitting layers), a preferentially horizontal orientation of the TDMs is promoted, due to which, the NIR-PLEDs-1–2 exhibit an attractively high efficiency (ηmaxEQE = 3.1–4.7%; λem = 698 nm) as well as an almost negligible (

Based on geometrical isomerisation of [Ir(C^N1)(C^N2)((N^O))]-tris-heteroleptic Ir(iii)-complexes, the augmented transition dipole transition (TMD) with a preferential horizontal orientation, which is beneficial for their NIR-phosphorescence, is reported.

Despite the cost-effective and large-area scalable advantages of NIR-PLEDs based on iridium(III)-complex-doped polymers, the intrinsic phase-separation issue leading to inferior device performance is difficult to address. In this study, taking the vinyl-functionalized [Ir(iqbt)2(vb-ppy)] (Hqibt = 1-(benzo[b]-thiophen-2-yl)-isoquinoline; vb-Hppy = 2-(4′-vinylbiphenyl-4-yl)pyridine) as the polymerized complex monomer, two series of Ir(III)-complex-grafted polymers Poly(NVK-co-[Ir(iqbt)2(vb-ppy)]) and Poly((vinyl-PBD)-co-NVK-co-[Ir(iqbt)2(vb-ppy)]) (NVK = N-vinyl-carbazole; vinyl-PBD = 2-(4-(tert-butyl)phenyl)-5-(4′-vinyl-[1,1′-biphenyl]-4-yl)-2,5-dihydro-1,3,4-oxadiazole) are obtained, respectively. Moreover, by using the bipolar Ir(III)-complex-grafted polymer further doped or grafted with an electron-transport unit as the emitting layer (EML), reliable NIR-PLEDs are realized. In particular based on the concurrent covalent-linkages of both the Ir(III)-complex and the vinyl-PBD towards the carrier-balanced NIR-PLED-III, the achievement of an almost negligible (

Despite the domination of conventional [Ir(C^N)2(L^X)]-bis-heteroleptic iridium(III)-complexes with NIR-phosphorescence (NIR = near-infrared) as dopants for reliable NIR-OLEDs/PLEDs (organic/polymer light-emitting diodes), the achievement of high performance remains a real challenge. In this study, taking Hiqbt (1-(benzo[b]-thiophen-2-yl)-isoquinoline) as the C^N ligand and one of the asymmetric Schiff-base ligands with different electronic effects as the N^O-ancillary ligand, three novel C1-symmetric [Ir(C^N)2(N^O)]-bis-heteroleptic iridium(III)-complexes 1–3 were developed. With contributions from the TDM (transition dipole moment) and the emitting dipole orientation induced by the N^O-ancillary electronic effects, the doped NIR-PLEDs-1–3 exhibited attractive high efficiency (ηmaxEQE = 3.3–5.6%; λem = 708–712 nm) apart from the almost negligible (

Thanks to the straightforward white light of single grafting-type polymers based on earth-abundant Zn(ii)-complexes, producing cost-effective flexible WOLEDs/WPLEDs with good device performance remains a formidable challenge. Herein, by using the polymer Poly(NVK-co-[Zn2(MP)3(OAc)]) with excellent physical properties for single-layer WPLEDs, record-high efficiencies (ηMaxc = 13.0 cd A−1, ηMaxp = 6.1 lm W−1 and ηMaxEQE = 9.2%) and low (ca. 25%) efficiency roll-off compared to previous organo-Zn2+-based WOLEDs/WPLEDs are realized. This finding renders single Zn(ii)-complex-grafted polymers a new route to low-cost and large-area flexible WPLEDs for potential full-colour flat displays., Using [Zn2(MP)3(OAc)]-grafted polymer as a single emitting layer, record-high efficiencies and weak (ca. 25%) efficiency roll-off are realized for cost-effective and large-area flexible WPLEDs.

Through the replacement of the β-diketonate Hbtfa (Hbtfa=4,4,4-trifluoro-3-hydroxy-1-phenylbutanone) with the bis-β-diketonate ligand H2btp (H2btp=1,3-bis(4,4,4-trifluoro-1,3-dioxobutyl)benzene), structure converts from mononuclear [Ir(iqbt)2(btfa)] (1) (Hiqbt=1-(benzo[b]-thiophen-2-yl)-isoquinoline) to asymmetric dinuclear [(iqbt)2Ir-(btp)-Ir(iqbt)2] (2) framework toward larger molecule conjugation. Upon a significant bathochromic shift into the restrictive near-infrared (NIR) regime (λem=722 nm for complex 2 and 698 nm for complex 1), the superior phosphorescence (Φem=0.15 and τ = 1.27 μs) of complex 2 to that (Φem=0.08 and τ = 0.78 μs) of complex 1 is also approached. Moreover, within the realization of their solution-processed NIR polymer light-emitting diodes (NIR-PLEDs-I-II), complex-2-doped NIR-PLED-II in the presence of TmPyPB-assisted (TmPyPB=1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene) carrier balance, exhibits the attractive electroluminescent (EL) performance with both ηEQEmax= 3.11% and almost negligible efficiency-roll-off.

In this study, a polymerizable terpyridine 2-(4-(4-(4-vinylbenzyloxy)phenyl)-6-(pyridin-2-yl)pyridin-2-yl)pyridine was synthesized, with N-(2-hydroxyethyl)acrylamide (HEAA) used to obtain an amphipathic polymer (Poly) through free radical polymerization. Then, Poly was coordinated with LnCl3 or Ln(ABM)3(H2O)2 (ABM = 4,4,4-trifluoro-1-phenylbutane-1,3-dione; Ln = Eu or Gd) in an equimolar ratio and a series of terpyridine-based Ln(III)-metallopolymer Poly-Eu or Poly-Eu-ABM obtained. The results strongly suggested that Poly-Eu exhibited aggregation-induced lanthanide emission. In contrast, after the introduction of a secondary sensitizer, ABM to Poly-Eu, aggregation-caused quenching effects were observed in Poly-Eu-ABM. In addition, both Poly-Eu and Poly-Eu-ABM were applied as fluorescence sensors to selectively detect pyrophosphate (PPi) among a series of different anions and the detection limit found to be at the nanomolar scale. Furthermore, high PPi sensitivity and selectively, low toxicity, and water solubility of this metallopolymer matrix Poly-Eu-ABM were used to detect PPi in living cells.

Through the utilization of Hiqbt (1-(benzo[b]-thiophen-2-yl)-isoquinoline) or Hdpbq (2,3-diphenyl benzo[g]quinoxaline) as the C^N main ligand and 8-Hq (8-hydroxyquinoline) as the N^O ancillary ligand, two [Ir(C^N)2(N^O)]-characterized heteroleptic complexes [Ir(iqbt)2(8-q)] (1) and [Ir(dbpq)2(8-q)] (2) with desirable soluble and NIR-phosphorescent properties (λem = 687 nm with a shoulder at 756 nm, lifetime τ = 0.73 μs and quantum efficiency Φem = 0.16 for complex 1 versus λem = 786 nm, lifetime τ = 0.47 μs and quantum efficiency Φem = 0.05 for complex 2) are obtained, respectively. In comparison, the distinctive bathochromatic shift into a typical NIR region of complex 2, arisen from the large-molecule-conjugation-induced narrow energy gap, gives rise to its relatively lower quantum efficiency than that of complex 1.

For Zn-nanopapers obtained from grafting of Zn(II)-terpyridine complex (Zn-tpy) into tCNFs (2,2,6,6-tetramethylpiperidine-1-oxyl radical, TEMPO, oxidized cellulose nanofibrils), their optical hazes were first found to be highly dependent on alcohol-characteristic solvent stimulation. By addressing the controllable issue of benzyl alcohol (BA) disposal, the optical haze of Zn-nanopaper was adjusted to regulate from BA-induced instability wrinkling and swelling patterns, which was dictated by Zn-nanopaper thickness. Moreover, upon long-term UV radiation, these Zn-nanopapers exhibited stable UV-blocking, which, together with the optical haze adjustment, offered an opportunity for utilization in fluorescent lamps, flat panel displays or glass walls.

Two mononuclear LnIII compounds, in which each LnIII is eight-coordinated, namely [Ln(L)(tmpd)] (Ln = Dy (1) or Er (2)), have been prepared using a multichelating Schiff base ligand N,N′-bis(2-hydroxy-5-methyl-3-formylbenzyl)-N,N′-bis-(pyridin-2-ylmethyl)ethylenediamine (H2L) and a bidentate chelating β-diketonate ligand (tmpd). The local geometry of the LnIII ions in 1 and 2 is close to the D2d symmetry. Notably, magnetic studies reveal that compound 2 displays no slow relaxation of magnetization while compound 1 exhibits single-molecule magnet (SMM) behaviour in the absence of a static magnetic field, with an effective energy barrier (Ueff) of 66.81 cm−1 (96.63 K). To deeply understand their different magnetic behaviours, the magnetic anisotropy of 1 and 2 is systematically studied by ab initio calculations. There was an obvious difference between the first excited state (KD1) and the experimental Ueff in 1 because the QTM within KD0 is not completely prohibited and the residual QTM could lead to a large discrepancy between experimentally-fitted Ueff and ab initio calculated crystal field splitting. No temperature/frequency dependence is recorded in the ac susceptibility of 2 because the ab initio magnetic easy axis of 2 does not lie close to any atom of the first sphere since it tries to avoid any strong electrostatic repulsion. Moreover, the gXY value of KD0 of 2 is larger than that of 1 by three orders of magnitude leading to the probability of stronger QTM within KD0 of 2.

Colour-tunable polymer light-emitting diodes (PLEDs) were realized by tuning the concentration of an Eu3+-complex in the emitting-layer (EML) and the thickness of the hole-blocking BCP layer (BCP = 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) in a double-emitting-layer (dEML) configuration. The dEML used PVK:complex 2 (PVK = poly(N-vinylcarbazole); H2Salen = N,N′-bis(salicylidene)cyclohexane-1,2-diamine and HDBM = dibenzoylmethane for [Zn(Salen)(μ-OAc)Eu(DBM)2] (2)) as EML1 and Alq3 as EML2. The efficiencies (0.32–0.39 cd A−1, 0.54–0.56% and 0.99–1.10 lm W−1) were obtained from organo-Eu3+ incorporated WPLEDs with a complex-2-doping content of 20 or 30 wt% and 20 nm BCP thickness. The WPLEDs exhibited low turn-on voltage (6.0–7.5 V) and low efficiency-roll-off, which are advantageous to organo-Eu3+ doped WOLEDs.

Chiral NIR-light emitters [Pt(iqbt)(S-Ln)] (1–4) were used as dopants to produce CP-NIR-PLEDs displaying λem of 732 nm, ηMaxEQE of 0.87–0.93%, and gEL of up to 10−3.

Through free-radical copolymerization of the Yb3+-centered near-infrared (NIR) luminescent complex monomer [Zn(L1)(4-vinyl-Py)Yb(L2)3] (2) (H2L1 = N,N’-bis(salicylidene)−1,2-diamine; 4-vinyl-Py = 4-vinyl-pyridine and HL2 = (Z)−3-methyl-1-phenyl-4-(2,2,2-trifluoro-1-hydroxyethylidene)−1H-pyrazol-5(4H)-one) with NVK (N-vinylcarbazole), the obtained [Zn(L1)(4-vinyl-Py)Yb(L2)3]-grafted polymer Poly(NVK-co-2) with additional PVK (Poly(N-vinylcarbazole)) to Yb3+ ion Foster energy transfer is used as the emitting material of polymer light-emitting diode (PLED), exhibiting the Yb3+-centered NIR outputs at 980 nm with a maximum efficiency of 0.049% (at 5.62 mA/cm2) and a maximum irradiance of 78.68 μW/cm2 (at 16 V), respectively. This superior performance to those of previously reported organo-Yb3+-doped polymer systems, together with the characters of low turn-on voltage of 7 V and weak efficiency-roll-off (0.049–0.031% upon 5.62–233.6 mA/cm2), indicates that organo-Yb3+-grafted polymer is an effective strategy to develop PLEDs with the wavelength extended to 980 nm.

Through self-assembly of the typical β-diketone ligand HBTFA (HBTFA = 4,4,4-trifluoro-1-phenyl-1,3-butanedione) with LnCl3·6H2O in the presence of Et3N, the six-tenth in the η2-Mode I and the four-tenth in the μ-(O)-η2-bridging Mode II of the ten BTFA− ligands, together with the involvement of two μ3-(OH)− anions, two μ1-coordinating H2O and two μ2-bridging H2O molecules, endow the formation of homoleptic cyclic tetranuclear complexes [Ln4(BTFA)10(μ3-OH)2(H2O)4] (Ln = La, 1; Eu, 2; Tb, 3 or Gd, 4), respectively. Moreover, attributing to effective ligand-to-Ln3+ transfer energy, color-purity red-light (ΦLEu = 20.1%) for complex 2 while few near-white-light (Φem = 6.4%) for complex 3 are exhibited, respectively, despite the (μ3-OH)−-and-H2O-induced OH-oscillators surrounded from the four Ln3+ ions.

Recent materials research based on fluorescent nanocelluloses (NCs) used in the field of sensing and bioimaging is reviewed. Many designed morphologies have been reported, such as nanoparticles, fibers, nanopapers, hydrogels and aerogels, that have been produced by physical or chemical methods. In the field of sensing and bioimaging, these studies have involved, but not been limited to, special optical properties including fluorescence, long-lived luminescence, polarized light, and/or aggregation-induced emission. The fluorescence sensing platforms can be categorized according to stimuli such as pH and temperature, as well as the presence of toxic compounds, and anions and metal cations. In addition, NCs exhibit unique low toxicity, good biocompatibility, biodegradability and cell membrane penetration, and can be modified into fluorescent nanoprobes for in vivo imaging and tracing. As an excellent platform for fluorescent sensing and bioimaging, NCs are bound to be increasingly studied and widely applied in the field of production and life sciences.

A new irreversible solvatochromic Zn-nanopaper has been produced through the coordination-driven assembly of Zn(II)-terpyridine complex (Zn-tpy) on the surface of 2,2,6,6-tetramethylpiperidine-1-ox...

Through copolymerization of MMA (methyl methacrylate) with the vinyl-functionalized and tris-pyrazolonate hetero-binuclear complex monomer [Zn(L1)(4-vinyl-Py)Yb(L2)3] (3;H2L1 = N,N′-bis(salicylidene)cyclohexane-1,2-diamine; 4-vinyl-Py = 4-vinyl-pyridine and HL2 = (Z)-3-methyl-1-phenyl-4-(2,2,2-trifluoro-1-hydroxyethylidene)-1H-pyrazol-5(4H)-one), the obtained PMMA-supported grafting hybrid materials Poly(MMA-co-3) exhibit ideal physical properties including the desirable Yb3+-centered NIR efficiency (ΦYbL up to 1.29%).

Through the CH3ONa-catalyzed two-step-transesterification procedure from DMC (dimethyl carbonate) and α,ω-alkanediol (1,4-butanediol (BD), 1,5-pentanediol (PD), 1,6-hexanediol (HD) or 1,4-benzenedimethanol (BDM)), semi-crystalline poly(alkylene carbonate)s with Mn (number-average molecular weight) of 104 g/mol are obtained, respectively. Toward their desirably high Tm (melt-temperature), the equal [-OC(O)OCH3]/[-CH2OH] molar ratio for the obtained oligomers should be confirmed in the first-step-transesterification, and the chopping effect endowed from incomplete diols contributes to the restrictive polymer chain-growth.

An CH3CH2ONa-catalyzed two-step-transesterification procedure from DEC (diethyl carbonate) and α,ω-alkanediol (1,4-butanediol (BD), 1,5-pentanedoiol (PD) or 1,6-hexanediol (HD)) was adopted for the production of semi-crystalline poly(alkylene carbonate) with Mn (number-average molecular weight) size up to 104 g/mol. In the first-step-transesterification, the equal [ OC(O)OCH2CH3]/[ OH] molar ratio for the obtained oligomers should be confirmed, while the chain-growth between OH and ethyl-carbonate-incorporated oligomers and the chopping effect endowed from incomplete diols and hydroxyl-carbonates co-operate during the second-step-transesterification.

Tuning the magnetic dynamics of single-molecule magnets (SMMs) is a crucial challenge for chemists. Some feasible approaches have been developed to understand parts of the magneto-structural correlations and regulate the relaxation behaviors via rational design. Herein, the syntheses, structures and magnetic properties of two mononuclear DyIII SMMs are reported. The first structural motif reveals a trigonal dodecahedron (D2d) N2O6 coordination environment in 1, while the second one displays a square antiprismatic configuration (D4d). A DyDy distance of 8.589 A in 1 is clearly shorter than that of 2 (10.433 A) because of the existence of ππ stacking between benzene rings from two adjacent dbpy molecules in 1. The temperature and frequency-dependent out-of-phase ac susceptibility peaks were observed in the absence of a static dc field for 1 and 2. Two distinct thermal relaxation processes were observed in 1, while 2 exhibits one thermal relaxation process. It is interesting that the quantum tunneling of magnetization (QTM) was suppressed when optimum dc fields (1000 Oe) were applied. From ab initio calculations, the energies of the first excited state (KD1) are indeed close to the experimental relaxation energy barrier (Ueff) under zero dc field, which also reveals the typical features associated with the SMM behavior. In detail, the Ueff values are 103.62 cm-1 (149.87 K) as well as 55.10 cm-1 (79.69 K) for 1 and 116.07 cm-1 (167.87 K) for 2. The KD1 of 1 (133.82 cm-1) is slightly higher than that of 2 (129.31 cm-1). Comparing 1 and 2, this discrepancy from KD1 and the experimental Ueff might come from the apparent difference in the magnitude of tunneling probability between the two compounds. In other words, the intermolecular dipolar field plays an important role in their magnetic properties.

In heteroleptic iridium(III)-complexes capable of near-infrared (NIR) emitting, elaboration of their ancillary ligands is under-explored. In this study, through OH-modification at the 3-position of the picolinato (pic) ancillary ligand, we report two new complexes [Ir(iqbt)2(hpa)] (1; Hiqbt = 1-(benzo[b]-thiophen-2-yl)-isoquinoline; hpa = 3-hydroxypicolinate) with intramolecular hydrogen bonding and [Ir(iqbt)2(BF2-hpa)] (2) with further BF2-chelation, exhibiting desirable NIR luminescent properties (λem = 700 nm with a shoulder at 760 nm, lifetime τ = 2.13 μs and quantum yield ΦPL = 0.13 for 1versus λem = 692 nm with a shoulder at 756 nm, lifetime τ = 0.76 μs and quantum yield ΦPL = 0.08 for 2) in their respective solutions at RT. Moreover, two series of solution-processed NIR polymer light-emitting diodes (PLEDs-I-II) are fabricated from these two complexes, either in the presence or absence of a TmPyPB-assisted (TmPyPB = 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene) carrier balance, where a superior performance (ηmaxEQE = 2.22% and almost negligible efficiency-roll-off) is obtained for complex-1-doped NIR-PLED-II, with particular respect to facilitated electron transport.

Ring-opening metathesis polymerization (ROMP) of tetraallyl-functionalized complex monomer {[Zn2(L)4Ln(OAc)2]·(NO3)} (HL = 4-allyl-2-(1H-benzo[d]imidazol-2-yl)-6-methoxyphenol; Ln = Nd, 2; Ln = Yb, 3; or Ln = Er, 4) with NBE (norbornene) was used to prepare Zn2Ln-containing star-shaped metallopolymers with desirable physical properties, including efficient Ln3+-centered NIR luminescence. Using metallopolymer poly(3-co-NBE), with its charge-facilitated and BCP-assisted carrier transport properties (BCP = 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), as the emitting layer in a Yb3+-centered NIR-PLED afforded record electroluminescent properties (irradiance, 90.24 μW cm−2; efficiency, 0.065%) among previously reported organo-Yb3+-doped or organo-Yb3+-grafted polymer systems, with the advantages of a low turn-on voltage (5 V) and weak efficiency roll-off (≤30%) compared with organo-Yb3+-complex-based NIR-OLEDs.

Two Dy(III) single-ion magnets, formulated as [Dy(Phen)(Cl-tcpb)3] (Cl-1) and [Dy(Phen)(CH3O-tmpd)3] (CH3O-2) were obtained through β-diketonate ligands (Cl-tcpb = 1-(4-chlorophenyl)-4,4,4-trifluoro-1,3-butanedione and CH3O-tmpd = 4,4,4-trifluoro-1-(4-methoxyphenyl)-1,3-butanedione) with different substituent groups (–Cl/–OCH3) and auxiliary ligand, 1,10-phenanthroline (Phen). The Dy(III) ions in Cl-1 and CH3O-2 are eight-coordinate, with an approximately square antiprismatic (SAP, D4d) and trigonal dodecahedron (D2d) N2O6 coordination environment, respectively, in the first coordination sphere. Under zero direct-current (dc) field, magnetic investigations demonstrate that both Cl-1 and CH3O-2 display dynamic magnetic relaxation of single-molecule magnet (SMM) behavior with different effective barriers (Ueff) of 105.4 cm−1 (151.1 K) for Cl-1 and 132.5 cm−1 (190.7 K) for CH3O-2, respectively. As noted, compound CH3O-2 possesses a higher effective barrier than Cl-1. From ab initio calculations, the energies of the first excited state (KD1) are indeed close to the experimental Ueff as 126.7 cm−1 vs. 105.4 cm−1 for Cl-1 and 152.8 cm−1 vs. 132.5 cm−1 for CH3O-2. The order of the calculated energies of KD1 is same as that of the experimental Ueff. The superior SIM properties of CH3O-2 could have originated from the larger axial electrostatic potential (ESP(ax)) felt by the central Dy(III) ion when compared with Cl-1. The larger ESP(ax) of CH3O-2 arises from synergic effects of the more negative charge and shorter Dy–O distances of the axial O atoms of the first sphere. These charges and distances could be influenced by functional groups outside the first sphere, e.g., –Cl and –OCH3.

Based on copolymerization of NVK (N-vinylcarbazole) with an efficient Yb3+-centered NIR luminescent complex monomer [Zn(L1)(4-vinyl-Py)Yb(L2)3] (3) (H2L1 = N,N′-bis(salicylidene)cyclohexane-1,2-diamine, 4-vinyl-Py = 4-vinyl-pyridine, and HL2 = (Z)-3-methyl-1-phenyl-4-(2,2,2-trifluoro-1-hydroxyethylidene)-1H-pyrazol-5(4H)-one), the obtained single Zn2+–Yb3+-containing metallopolymer Poly(NVK-co-3) with an additional PVK (poly(N-vinylcarbazole))-to-Yb3+ Foster energy transfer was used as the emitting layer for the realization of NIR PLEDs. Moreover, among the Yb3+-centered NIR PLEDs, the superior performance (irradiances of 80.14–85.63 μW cm−2 and efficiencies of 0.05–0.058%) of the 75 : 1 feeding devices, the advantages of a low turn-on voltage (5–8 V), and the weak efficiency-roll-off relative to that of the small-molecule organo-Yb3+-based NIR OLEDs render the Yb3+-containing metallopolymer a new platform for PLEDs with wavelength above 900 nm.

Through the doping of red-light-emitting [Eu(BA)3(5-Br-2,2′-bpy)] (2; HBA = 1-phenyl-1,3-butanedione; 5-Br-2,2′-bpy = 5-Br-2,2′-bipyridine) and blue-green-light-emitting [Tb(BA)3(5-Br-2,2′-bpy)] (3) into PMMA (poly(methyl methacrylate)), the obtained 2@3@PMMA (1[2/3 = 1:10]:200) exhibits color-tunable white-light. Moreover, using it as the guest of the emitting layer, a single-component white polymer light-emitting diode (WPLED) with good color stability and ultra-high color rendering index (CRI) of 86–92 is also realized.

A new kind of highly red emissive and transparent nanopapers as ultraviolet filter are produced from lanthanide complex Eu(TTA)3(H2O)2 grafted nanofibrillated cellulose (NFC) by a filtration process using a Buchner funnel. The nanopapers Eu-NFC 1–4 with different thickness (0.023 mm, 1; 0.04 mm, 2; 0.081 mm, 3 and 0.1 mm, 4) possess a fibres with dimensions of approximately 50 nm in diameter and several micrometres in length. Those nanopapers exhibit excellent ultraviolet A (UVA; 320–400 nm) filter property and high optical transmittance (>73% at wavelength of 600 nm). The presence of Eu(TTA)3(H2O)2 in Eu-NFC nanopapers can block 97% UVA (at 348 nm) light and convert it into pure red emission (CIE: x = 0.663, y = 0.333) through the efficient triplet-triplet energy transfer process. The efficient red emission can significantly improve the photo-stability of β-diketones type UVA filter. It can sustain for 10 h without decomposition under UV irradiation at 365 nm, which makes it possible to be applied in UVA filters. Moreover, its low coefficient of thermal expansion (CTE: 6.39 ppm K−1 of nanocellulose), is superior to petroleum-based materials for red organic light-emitting devices.

Through the self-assembling of Ln(OAc)3⋅6H2O (Ln = Eu or Tb) with the chromium(III)-complex precursor [Cr(L)Cl(H2O)] formed from the oxidation and the coordination reactions of CrCl2 and the Salen-type Schiff-base ligand H2L (N,N’-bis(3-methoxy-salicylidene)cyclohexane-1,2-diamine), two hetero-binuclear complexes [Cr(L)Cl(μ1-OAc)Ln(μ2-OAc)Cl(H2O)] (Ln = Eu, 1 or Tb, 2) were obtained, respectively. Moreover, attributing to effective Eu3+-to-Cr3+ energy transfer, the [Cr(L)Cl(μ1-OAc)Eu(μ2-OAc)Cl(H2O)] (1) exhibits the significantly improved Cr3+-characteristic near-infrared (NIR) phosphorescence in comparison to that of the Cr(III)-complex precursor [Cr(L)Cl(H2O)] or the [Cr(L)Cl(μ1-OAc)Tb(μ2-OAc)Cl(H2O)] (2).

Based on the quaternary copolymerization of the vinyl-functionalized monomers of a Schiff-base HVBMP (2-(((4-vinylphenyl)imino)methyl)phenol), its boride BF2-VBMP (2,2-difluoro-3-(4-vinylphenyl)-2H-2λ4,3λ4-benzo [e] (Schubert and Kim, 2005; Shao et al., 2019; Wang et al., 2011) [1,3,2]oxazaborinine) and an organo-Eu3+- complex [Eu(TTA)3(4-VP-BPI)] (HTTA = 2-thenoyltrifluoroacetonate; 4-VB-PBI = 1-(4- vinylbenzyl)-2-(pyridin-2-yl)-1H-benzo [d]imidazole)) with MMA (methyl methacrylate), a single-component white-light-emitting ((CIE coordinate (0.320, 0.341), CRI = 95, CCT = 6078 K and Φ = 4.31%; λex = 380 nm) Eu3+-metallopolymer Poly[HVBMP-co-(BF2-VBMP)-co- Eu-co-MMA] (0.5:0.5:1:100) is obtained. Moreover, upon spin-coating of the Eu3+-metallopolymer onto a near-ultraviolet (n-UV) InGaN chip, the n-UV white light-emitting diode (n-UV-WLED) characteristic of the high-quality white-light (CIE coordinate (0.337, 0.367), CRI = 83 and CCT = 5318 K) with the luminance of 2880 cd/m2 at the applied voltage of 4 V, is successfully developed. This result shows that single-component Eu3+-metallopolymer capable of the BF2-chelation-assisted trichromatic white-light modulation, endows a promising opportunity to the potential n-UV-WLEDs.

Through the single-nodal copolymerization of MMA (methyl methacrylate) and a vinyl-containing complex monomer [Zn(L)(4-vinyl-Py)Nd(NO3)3] (2; H2L = N,N′-bis(3-methoxy-salicylidene)ethylene-1,2-diamine; 4-vinyl-Py = 4-vinyl-pyridine) with the both 1π-π* and 3π-π* sensitizing approach to Nd3 + ion, the Zn2 +-Nd3 +-containing metallopolymer Poly(MMA-co-2) exhibits good physical properties including an attractive Nd3 +-centered NIR sensitization efficiency (ΦLNd = 1.22% and η = ΦLNd/ΦNdNd = 82%).

Within series of Ln 3 -grafted polymers Poly({[Ln 3 (L) 4 (NO 3 ) 6 ]·(NO 3 )·(H 3 O) 2 }-co-NBE) (Ln = La, 1 ; Ln = Eu, 2 ; Ln = Tb, 3 ; Ln = Nd, 4 ; Ln = Yb, 5 ; Ln = Er, 6 or Ln = Gd, 7 ) obtained from ring-opening metathesis polymerization (ROMP) of norbornene (NBE) with each of allyl-functionalized complex monomers {[Ln 3 (L) 4 (NO 3 ) 6 ]·(NO 3 )·(H 3 O) 2 } ( HL = 4-allyl-2-(1 H -benzo[ d ]imidazol-2-yl)-6-methoxyphenol), PNBE-assisted effective energy transfer renders Poly(3- co -NBE) Tb 3+ -centered highly luminous color-purity green-light with an attractive quantum yield of 87% and efficient near-infrared (NIR) luminescence ( Φ Nd L = 0.61%; Φ Yb L = 1.47% and Φ Er L = 0.03%) for Nd 3+ -, Yb 3+ - or Er 3+ -grafted polymers.

Through terpolymerization of vinyl-functionalized complex monomers 2-3 ([Zn(L)(4-vinyl-Py)Ln(BA)2(NO3)] (Ln = Eu, 2 or Ln = Tb, 3; H2L = N,N′-bis(salicylidene)cyclohexane-1,2-diamine; 4-vinyl-Py = 4-vinyl-pyridine; HBA = 1-phenyl-1,3-butanedione) with dual emissions, and/or blue-light-compensatory [Zn(L)(4-vinyl-Py)Gd(BA)2(NO3) (4) with MMA (methyl methacrylate), we offer a robust pathway to single-component while heterometallic-containing metallpolymer-type hybrid materials with color-tunable white-light as featured like Zn2+-Eu3+-Tb3+-containing Poly(2-co-MMA-co-3) and Zn2+-Eu3+-Tb3+-Gd3+-containing Poly(MMA-co-2-co-3-co-4). Moreover, by a strategy to control of optimal dye contents for managing Tb3+ to Eu3+ energy transfer and excimer formation, their intrinsic white-light emissions can be easily optimized from a precise control of primary-chromophore content and excitation wavelength, rendering both a highly luminous efficiency (15.6%) and an excellent color-quality (CIE (Commission International De L'Eclairage) coordinates of 0.334–0.344, 0.332–0.355; CCTs (corrected color temperature) of 5051–5404 K and ultra-high CRIs (color rendering index) up to 87-91) with potentials for future color-critical high-level applications.

Through the ring-opening metathesis polymerization (ROMP) of norbornene (NBE) with each of allyl-containing complex monomers [Zn(L)2(µ1-OAc)Ln(µ2-OAc)2] (Ln=La, 1; Nd, 2; Yb, 3; Er, 4 or Gd, 5; HL=4-allyl-2-(1H-benzo[d]imidazol-2-yl)-6-methoxyphenol), a series of ZnLn-grafted polymers Poly([Zn(L)2(µ1-OAc)Ln(µ2-OAc)2]-co-NBE) with desired physical properties were obtained, respectively. Within near-infrared (NIR) luminescent polymers, Poly(3-co-NBE) endows an attractive quantum yield of 1.47% in solid state, and exhibits an effective prevention of high-concentration self-quenching.

Through the ring-opening metathesis polymerization (ROMP) of norbornene (NBE) with each of obtained allyl-containing complex monomers [Zn(L) 2 (Py)Ln(NO 3 ) 3 ] (Ln = La, 1 ; Nd, 2 ; Yb, 3 ; Er, 4 or Gd, 5 ; HL = 4-allyl-2-(1 H -benzo[ d ]imidazol-2-yl)-6-methoxyphenol; Py = pyridine), a series of metallopolymers Poly(NBE- co -[Zn(L) 2 Ln(Py)(NO 3 ) 3 )]) were obtained, respectively. Especially for Poly(NBE- co -2) and Poly(NBE- co -3) , covalently-bonded grafting endows significantly improved physical properties including efficient NIR luminescence ( Φ Nd L = 0.63% and Φ Yb L = 1.43%) in solid state.

Through terpolymerization of the red-light complex monomer [Eu(tta)3(4-vp-2,2′bpy)] (2; Htta = 2-thenoyltrifluoroacetone; 4-vp-2,2′-bpy = 2-(pyridin-2-yl)-5-(4-vinylphenyl)pyridine), blue-green-light complex monomer [Zn(L)(4-vinyl-Py)Gd(NO3)3] (8; Salen-type H2L = N,N′-bis(3-methoxy-salicylidene)phenylene-1,2-diamine; 4-vinyl-Py = 4-vinyl-pyridine) with MMA (methyl methacrylate), the obtained Eu3+–Zn2+–Gd3+-containing metallopolymer Poly(2-co-MMA-co-8) (120 : 1[2/8 = 2 : 1 or 1 : 2]) exhibits stoichiometry-dependent color-tuning photoluminescence due to effective Zn2+–Gd3+–Salen to Eu3+ energy transfer. Moreover, using them as the corresponding emitting layers, a high color-purity red-light polymer light-emitting diode (PLED) with a luminous efficiency of 0.037 lm W−1 and first-example Ln3+-containing-metallopolymer-based WPLED with an eternal quantum yield of 0.003% is realized.

By anchoring lanthanide coordination monomers onto a PMMA polymer backbone via a pre-designed vinylbenzyl-substituted NTB-type ligand, we succeeded in the fabrication of homo or hetero Ln-metallopolymers that can emit tunable and designable multicoloured photoluminescence as well as white light emission. Copolymerization results in the fine-tuning of the energy state of the ligand in the metallopolymer compared with that in the coordination monomer, thereby changing the energy transfer efficiency to Eu3+ and Tb3+ centers in opposite ways. And further designing of hetero-lanthanide metallopolymers leads to additional energy transfer between Eu3+ and Tb3+, facilitating the generation of pure white light emission. In general, the facile and controllable synthesis procedure, versatile and reproducible combination of lanthanides, ligands and polymer backbones, and relatively high white light emitting luminous efficiency (>5%) prove this method to be promising in future lighting WPLED applications.

Through an approach of pre-coordination and following terpolymerization from vinyl-functionalized complex monomers [Ln(TTA)3(4-VB-PBI)] (Ln = Eu, 2; Ln = Tb, 3 and Ln = Gd, 4; HTTA = 2-thenoyltrifluoroacetonate; 4-VB-PBI = 1-(4-vinylbenzyl)-2-(pyridin-2-yl)-1H-benzo[d]imidazole) with methyl methacrylate, the first example of a single-component Eu2+–Tb3+–Gd3+-grafted polymer Poly(MMA-co-2-co-3-co-4) was obtained. Moreover, control of an optimal dye content for suppressing Tb3+ to Eu3+ energy transfer and exciton formation provides new perspectives for hetero-Ln3+-grafted polymers as featured in Poly(MMA-co-2-co-3-co-4) with color-tuning to direct white-light (Commission International De L'Eclairage coordinates of x = 0.322, y = 0.331; corrected color temperature of 5979 K; and color rendering index up to 94), including a highly luminous efficiency of 17.8%.

Through the radical copolymerization of MMA (methyl methacrylate) with a vinyl-containing complex monomer {[Yb4(L)2(HL)2(μ3-OH)2(NO3)2]·(NO3)2} (1; H2L = N,N′’-bis-(5-(3′-vinylphenyl)-3-methoxy-salicylidene)cyclohexane-1,2-diamine), the first example of PMMA-supported and Yb4(Salen)4-containing metallopolymer Poly(1-co-MMA) exhibits significantly improved physical properties besides relatively higher NIR quantum yields (ΦYbYb = 1.18% and ΦLYb = 0.86%) than those (ΦYbYb = 1.02–1.04% and ΦLYb = 0.73–0.75%) of complex monomer 1 in solution and 1@PMMA in solid state.

Based on the free-radical copolymerization of the green-light complex monomer [Tb(eb-PMP)3(4-VB-PBI)] (2; Heb-PMP = 4-(2-ethylbutanoyl)-1-phenyl-3-methyl-1H-pyrazol-5(4H)-one; 4-VB-PBI = 1-(4-vinylbenzyl)-(pyridin-2-yl)-1H-benzo[d]imidazole) with NVK (N-vinylcarbazole), the obtained Tb3+-containing metallopolymer poly(NVK-co-2) with an energy transfer from additional PVK to Tb3+ ion was used as the emitting material of polymer light-emitting diodes (PLEDs); it exhibited record renewed efficiencies (24.63 cd A−1, 7.81%, and 6.45 lm W−1) of Tb3+-based extreme colour-purity green-light PLEDs and superior performance of colour-stability and low efficiency roll-off to small-molecule Tb3+-complex's OLEDs.

Several unsymmetrical Schiff-base mononuclear and binuclear manganese(III), cobalt(III) and chromium(III) complexes have been designed, synthesized and applied to the alternating ring-opening copolymerization of cyclohexene oxide and maleic anhydride with the optimized conditions. Experimental results show that these complexes are effective in the catalytic copolymerization. Among the six complexes, the binuclear complexes exhibited better catalytic activity than mononuclear complexes under the same conditions. The highest molecular weight (24,600 g mol−1) of copolymer with a narrow polydispersity (1.07) and higher conversion of the monomer (95%) were achieved when using binuclear chromium(III) complex, followed by the manganese(III) complex and the cobalt(III) complex showed relatively lower activity at the same conditions. It is due to maybe existed an intramolecular bimetallic synergistic effect in the binuclear catalysts system different from the mononuclear catalysts system.