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Visible and near-infrared (NIR) light dual-band photodetectors (PDs) have potential applications in signal detection, bioimaging, optical communications and safety monitoring. Herein, we report an ultrafast perovskite/organic heterojunction dual-mode PD with a voltage-modulated photoresponse range in visible and NIR spectra. The PD, comprising a perovskite layer to absorb visible light (500-810 nm) and an organic bulk heterojunction layer for NIR light absorption (810-950 nm), exhibited a switchable spectral response in the visible or NIR bands. The voltage-modulated visible and NIR photoresponses of the PD were attributable to controlled charge photogeneration in perovskite and organic blend thin films under different bias polarities. The device exhibited peak responsivities of 93.5 and 102.2 mA/W in the visible and NIR bands, respectively; a high detectivity of 4.3 × 10

We designed and synthesized a new class of six phosphorescent [3 + 2 + 1] iridium(III) complexes

A new class of yellow- to red-emitting carbazolylgold(III) complexes containing isomeric thienopyridine or thienoquinoline moieties in the cyclometalating ligand has been designed and synthesized, which showed high photoluminescence quantum yields of over 80% in solid-state thin films. The isomeric effect and extended π-conjugation of the N-heterocycles have been found to remarkably perturb the photophysical, electrochemical and electroluminescence properties of the gold(III) complexes. In particular, the operational lifetimes of organic light-emitting devices based on that incorporated with thieno[2,3-c]pyridine are almost three orders of magnitude longer than that incorporated with thieno[3,2-c]pyridine. This has led to long device operational stability with a LT70 value of up to 63 200 h at a luminance of 100 cd m−2 and a long half-lifetime of 206 800 h, as well as maximum external quantum efficiencies of up to 8.6% and 14.5% in the solution-processed and vacuum-deposited devices, respectively. This work provides insights into the development of robust and highly luminescent gold(III) complexes and the identification of stable molecular motifs for designing efficient emitters.

The saturated-blue phosphorescent OLEDs based on the [3+2+1] coordinated iridium(iii) complexes bearing the phenyl-3H-imidazo[4,5-b]pyridine-based (C^C) bidentate ligands, demonstrating an EQE of 11.2% and CIE (x,y) coordinates of (0.16, 0.07).

A series of carbazolyl ligands has been designed and synthesized through the integration of various electron-donating and electron-accepting motifs, including electron-donating 4-(diphenylamino)aryl and electron-accepting cyano and diphenylphosphine oxide moieties, for the development of a new class of gold(iii) complexes, where the energies of their triplet intraligand and ligand-to-ligand charge transfer excited states can be manipulated for the activation of thermally activated delayed fluorescence (TADF). Upon excitation, these complexes show high photoluminescence quantum yields of up to 80% in solid-state thin films, with short excited state lifetimes down to 1 μs. Vacuum-deposited and solution-processed organic light-emitting devices based on these complexes demonstrate promising electroluminescence (EL) performance with maximum external quantum efficiencies of 15.0% and 11.7%, respectively, and notably small efficiency roll-off values of less than 1% at the practical luminance brightness level of 1000 cd m

Constructing stable surface modification layer is an effective strategy to suppress dendrite growth and side reactions of Zinc (Zn) metal anode in aqueous Zn-ion battery. Herein, a multicomponent Cu-Zn alloy interlayer with superior Zn affinity, high toughness and effective inhibition effect on lattice distortion is constructed on Zn foil (Cu-Zn@Zn) to fabricate ultra-stable Zn metal anode. Owning to the advantages of high binding energy of Cu-Zn alloy layer with Zn atoms and less contact area between metallic Zn and electrolyte, the as-prepared Cu-Zn@Zn electrode not only restricts the aggregation of Zn atoms, but also suppresses the pernicious hydrogen evolution and corrosion, leading to homogeneous Zn deposition and outstanding electrochemical performances. Accordingly, the symmetric battery with Cu-Zn@Zn electrode exhibits an ultra-long cycle life of 5496 h at 1 mA cm

Here, we report the design and synthesis of a new class of fused heterocyclic alkynyl ligand-containing gold(iii) complexes, which show tunable emission colors spanning from the yellow to red region in the solid state and exhibit thermally activated delayed fluorescence (TADF) properties. These complexes display high photoluminescence quantum yields of up to 0.87 and short excited-state lifetimes in sub-microsecond timescales, yielding high radiative decay rate constants on the order of up to 106 s−1. The observation of the drastic enhancement in the emission intensity of the complexes with insignificant change in the excited-state lifetime upon increasing the temperature from 200 to 360 K indicates an increasing radiative decay rate. The experimentally estimated energy splitting between the lowest-lying singlet excited state (S1) and the lowest-lying triplet excited state (T1), ΔES1–T1, is found to be as small as ∼0.03 eV (250 cm−1), comparable to the value of ∼0.05 eV (435 cm−1) obtained from computational studies. The delicate choice of the cyclometalating ligand and the fused heterocyclic ligand is deemed the key to induce TADF through the control of the energy levels of the intraligand and the ligand-to-ligand charge transfer excited states. This work represents the realization of highly emissive yellow- to red-emitting gold(iii) TADF complexes incorporated with fused heterocyclic alkynyl ligands and their applications in organic light-emitting devices., We report the design of a new class of fused heterocyclic alkynyl ligand-containing gold(iii) complexes, which shows tunable emission colors spanning yellow to red region and exhibits thermally activated delayed fluorescence (TADF) properties.

A new class of C^C^N ligand-containing carbazolylgold(iii) dendrimers has been designed and synthesized. High photoluminescence quantum yields of up to 82% in solid-state thin films and large radiative decay rate constants in the order of 105 s−1 are observed. These gold(iii) dendrimers are found to exhibit thermally activated delayed fluorescence (TADF), as supported by variable-temperature emission spectroscopy, time-resolved photoluminescence decay and computational studies. Solution-processed organic light-emitting diodes (OLEDs) based on these gold(iii) dendrimers have been fabricated, which exhibit a maximum current efficiency of 52.6 cd A−1, maximum external quantum efficiency of 15.8% and high power efficiency of 41.3 lm W−1. The operational stability of these OLEDs has also been recorded, with the devices based on zero- and second-generation dendrimers showing maximum half-lifetimes of 1305 and 322 h at 100 cd m−2, respectively, representing the first demonstration of operationally stable solution-processed OLEDs based on gold(iii) dendrimers., A new class of carbazolylgold(iii) C^C^N dendrimers with thermally activated delayed fluorescence properties has been designed and synthesized for the realzaqtion of operationally stable solution-processed organic light-emitting devices.

Spectrally selective narrowband Si photodetection is critical for near-infrared (NIR) medical imaging, optical communication, light detection and autonomous mobiles. For conventional inorganic semiconductors such as silicon with broadband absorption from visible until 1.1 µm, it remains challenging to achieve narrowband photodetection without integrating optical filters. We demonstrate the very first narrowest NIR silicon photodetectors without any bandpass filter, reaching the full-width-at-half-maximum of only 26 nm at 912 nm. The narrowband response is inherently attributed to the resonant enhancement effect of optical microcavities formed by patterned Si nanograting combined with the organic D18:Y6 blend film. The Conductive-Atomic Force Microscope (C-AFM), Kelvin Probe Force Microscope (KPFM) and transient absorption (TA) spectroscopy characterization indicate effective charge transfer between Si and organic layers, significantly contributing to ultrafast photoresponse of 74 \(\mu s\). Therefore, this design concept opens up the new possibility of developing filter-less and effective low-cost NIR detection, enabling entirely new configurations of optical imaging devices with narrowband tunability for telecommunications and imaging applications.

Phosphorescent dopants are promising candidates for organic light-emitting diodes (OLEDs). Although it has been established that the out-coupling efficiency and overall performances of vacuum-deposited OLEDs can be significantly improved by a horizontal orientation of the dopants, no horizontally oriented gold(III) complexes have been reported to date. Herein, a novel class of tetradentate C^C^N^N ligand-containing gold(III) complexes with a preferential horizontal orientation successfully generated through a one-pot reaction is reported. These complexes demonstrate high photoluminescence quantum yields of 70 % and a high horizontal dipole ratio of 0.87 in solid-state thin films. Green-emitting OLEDs based on these complexes operate with a maximum external quantum efficiency of 20.6 % with an estimated out-coupling efficiency of around 30 %. A promising device stability has been achieved in the vacuum-deposited OLEDs, with operational half-lifetimes of around 37 500 h at 100 cd m-2 .

A new class of sky-blue- to green-emitting carbazolylgold(III) C^C^N complexes containing pyrazole or benzimidazole moieties has been successfully designed and synthesized. Through the judicious choice of the N-heterocycles in the cyclometalating ligand and the tailor-made carbazole moieties, maximum photoluminescence quantum yields of 0.52 and 0.39 have been realized in the green- and sky-blue-emitting complexes, respectively. Solution-processed and vacuum-deposited organic light-emitting devices (OLEDs) based on the benzimidazole-containing complexes have been prepared. The sky-blue-emitting device shows an emission peaking at 484 nm with a narrow full-width at half-maximum of 57 nm (2244 cm-1 ), demonstrating the potential of this class of complexes in the application of OLEDs with high color purity. In addition, high maximum external quantum efficiencies of 12.3 % and a long operational half-lifetime of over 5300 h at 100 cd m-2 have been achieved in the vacuum-deposited green-emitting devices.

We report two yellow-emitting cyclometalated gold(III) complexes serving as phosphorescent dopants for high-brightness solution-processed white organic light-emitting devices (WOLEDs). Dichromatic WOLEDs consisting of our newly synthesized Au–Y or Au–wY for yellow emission in combination with FIrpic for blue emission have been studied. Notably, white emissions in terms of Commission Internationale de L’Eclairage coordinates of (0.31, 0.39) and (0.40, 0.47) and color rendering indices of 66 and 69 have been accomplished with Au–Y- and Au–wY-based WOLEDs. In addition, current efficiencies of 26.0 and 25.7 cd/A corresponding to external quantum efficiencies of 11.0% and 10.5% are achieved and can be maintained at 19.8 and 25.3 cd/A at a high brightness level of 10,000 cd/m2 for these devices. Such high-performance WOLEDs in terms of small efficiency roll-offs over a wide brightness range are believed to be due to the use of gold(III) complexes with very short-lived emission lifetimes of ~ 1 μs, high photoluminescence quantum yields of up to 86% and broad yellow emission bandwidths of up to 107 nm. This study opens up the possibility of using solution-processable cyclometalated organogold(III) complexes with short-lived emissive excited states for the fabrication of WOLEDs, especially for high-brightness applications.

A simple one-pot two bond-forming reaction for the rapid construction of cyclometalated gold(III) complexes with fully π-conjugated tetradentate ligand is reported. The coupling of the bifunctional gold(III) precursor with the bifunctional aromatic compound has led to the formation of two regioisomers with either C- or N-coordination. Through monitoring by high-throughput high performance liquid chromatography, the regioselectivity of the reaction has been effectively tuned toward the formation of a single isomer, allowing easy separation of the metal complexes. The structures of the complexes have been determined by X-ray crystallography, and the photophysical, electrochemical, and electroluminescence (EL) studies have been carried out. Computational study has been performed to provide insights into the nature of the excited states. Isomeric effect has been shown to have a significant influence on the EL behavior of the organic light-emitting devices.

A series of arylgold(III) complexes of tridentate diphenylpyridine ligand incorporated with fluorene and its heterocyclic spiro derivatives, spiro[fluorene-9,9'-xanthene] and spiro[acridine-9,9'-fluorene], as auxiliary ligands has been prepared. This class of complexes exhibits high decomposition temperatures of up to 387 °C, excellent film morphologies in solid-state thin films with a root-mean-square roughness smaller than 0.20 nm, as well as high photoluminescence quantum yields of up to 0.72 in solid-state thin films. Solution-processed organic light-emitting devices (OLEDs) fabricated from this series of complexes as dopants show intense electroluminescence in the sky-blue region with maximum external quantum efficiencies of 10.0%. Taking advantage of their high thermal stability, vacuum-deposited OLEDs have also been fabricated and satisfactory operational lifetimes of ∼300 h have been recorded.

The advancement of high-efficiency luminescent and thermally stable organometallic complexes has offered opportunities for the commercialization of metal phosphors for fabricating organic light-emitting devices (OLEDs). Since the first report on the potential use of iridium(III) and platinum(II) complexes for applications in OLEDs in the late 1990s, extensive efforts have been made by researchers on the development of various heavy metal-containing compounds with rich photophysical and luminescence properties and the engineering of device architectures to improve device efficiencies. Apart from the more well-studied iridium(III) and platinum(II) complexes, complexes of gold(III) recently have demonstrated their capabilities to serve as phosphorescent or thermally stimulated delayed phosphorescent or thermally activated delayed fluorescent emitters, and their promising performances in OLEDs have attracted growing interest in the past decade. Nowadays, complexes of gold(III) with emission energies ranging from sky-blue to near-infrared with high electroluminescence performances have been obtained. In addition, high-efficiency vacuum-deposited and solution-processed OLEDs with benchmark efficiencies comparable to those of the iridium(III) and platinum(II) complexes have been realized. This Focus Review summarizes the development of various series of luminescent gold(III) complexes to date and highlights important milestones in the development and advancement of gold(III)-based OLEDs. Focus will be made on the molecular design strategies for gold(III) emitters for application as dopants in OLEDs, including those fabricated by vacuum-deposition and solution-processing techniques.

A new class of red- to near-infrared (NIR)-emitting cyclometalated alkynylgold(III) complexes was designed and synthesized. Red to NIR emission in the alkynylgold(III) complexes was realized, with the emission band maxima of the complexes in both solution and solid-state thin films found to extend to 823 and 730 nm, respectively. A small energy gap of down to 1.51 eV was achieved in the NIR-emitting complexes, as revealed from the electrochemical studies. Moreover, a large bathochromic shift of ∼1370 cm–1 can be obtained by simply changing the alkynyl ligand. NIR-emitting solution-processable organic light-emitting devices (OLEDs) were also realized, as exemplified by the electroluminescence properties with band maximum at 720 nm and Commission International de L’Eclairage coordinates of (0.67, 0.33) for devices based on complex 1b. This work not only demonstrates a design strategy to extend the emission of gold(III) complexes into the NIR regime but also represents the first report on gold(III)-based NIR...

Gold(iii) complexes are attractive candidates as phosphorescent dopants in organic light-emitting devices for high-luminance full-colour displays. However, no data on the stability of such devices have been reported to date. Through rational molecular design and synthesis, we have successfully generated a new class of cyclometalated gold(iii) C^C^N complexes with tunable emission colours spanning from sky-blue to red. These complexes exhibit high photoluminescence quantum yields of up to 80% in solid-state thin films, excellent solubility and high thermal stability. Solution-processable and vacuum-deposited organic light-emitting devices based on these complexes operate with external quantum efficiencies of up to 11.9% and 21.6%, respectively, and operational half-lifetimes of up to 83,000 h at 100 cd m−2. Cyclometalated gold(iii) complexes are shown to offer tunable emission colours spanning from sky-blue to red and enable the fabrication of phosphorescent organic light-emitting devices with high external quantum efficiency and long lifetimes.

Bipolar cyclometalated dendritic alkynylgold(III) complexes that exhibit excellent film morphologies in solid-state thin films have been designed and synthesized. Together with their high luminescence quantum yields, high performance solution-processable organic light-emitting devices have been realized, maintaining high external quantum efficiencies of >12% for dendrimers up to the second generation.

A series of cyclometalating tridentate N^C^N and tetradentate N^C^N^O ligand-containing complexes of earth-abundant nickel(II) has been designed and synthesized. Among them, the carbazolylnickel(II) complex demonstrates, for the first time, an orange color room-temperature luminescence. Such a complex is also found to exhibit intense luminescence with excited state lifetimes in the submicrosecond regime at 77 K, suggesting the triplet nature of the emissive state. Meanwhile, the self-assembly property of the tetradentate ligand-containing nickel(II) complex in solution has been investigated. Owing to its nearly perfect square planar geometry, as evidenced by X-ray crystal structure determination, it is found to exhibit self-assembly properties with the aid of π-π interactions and possibly weak Ni···Ni interactions, which have been supported by DFT calculations and NCI plot. Indeed, the ground-state aggregation behavior of this complex has been confirmed by concentration-dependent UV-vis absorption spectroscopy. Moreover, in the solution-induced aggregation studies, upon the addition of nonsolubilizing solvents, the emergence of low-energy absorption bands has been realized, and such a complex is found to demonstrate interesting self-assembly behaviors to offer well-defined and highly ordered supramolecular architectures.

A new class of pyrazine-based carbazole-containing gold(III) complexes featuring thermally stimulated delayed phosphorescence (TSDP) properties has been designed and synthesized. The emission colors are found to be sensitive to the coordinating atom of the carbazolyl ligands at the gold(III) center, with emission energies spanning from green to red. The efficiency of TSDP can be enhanced by lowering the polarity of the solvent, as supported by the variable-temperature emission and computational studies. Interestingly, a significant spectral shift in electroluminescence with the change of Commission Internationale de L'Eclairage (CIE) coordinates from (0.35, 0.60) to (0.44, 0.54) has been achieved by simply changing the host material from CBP to TmPyPB. Solution-processable organic light-emitting devices (OLEDs) have also been fabricated, with maximum current efficiencies of up to 22.4 cd A-1 and maximum external quantum efficiencies (EQEs) approaching 7.0%. A higher current efficiency of 35.1 cd A-1 and EQE of 10.7% can be achieved for the vacuum-deposited device based on 1, representing the first demonstration of pyrazine-based tridentate ligand-containing gold(III) complexes as phosphorescent material for OLED application.

A new class of fused heterocyclic tridentate ligand-containing alkynylgold(III) complexes with tunable emission color has been successfully designed and synthesized. Structural modification of the σ-donating fused heterocyclic alkynyl ligands, including substituted fluorene, carbazole, and triphenylamine, enables a large spectral shift of about 110 nm (ca. 3310 cm-1 ) that covers the green to red region to be realized with the same tridentate ligand-containing alkynylgold(III) complexes in solid-state thin films. Interestingly, the energy of the excimeric emission can be controlled by the rational design of the fused heterocyclic alkynyl ligands. Superior solution-processable organic light-emitting devices (OLEDs) with high external quantum efficiencies (EQEs) of 12.2, 13.5, 9.3, and 5.2 % were obtained with green, yellow, orange, and red emission. These high EQE values are comparable to those of the vacuum-deposited OLEDs based on structurally related alkynylgold(III) complexes.

We report the synthesis of alkynylgold(iii) complexes with an electron-transporting phosphine oxide moiety in the tridentate ligand and hole-transporting triarylamine moieties as auxiliary ligands to generate a new class of phosphine oxide-containing bipolar gold(iii) complexes for the first time. Such gold(iii) complexes feature high photoluminescence quantum yields of over 70% in 1,3-bis(N-carbazolyl)benzene thin films with relatively short excited-state lifetimes of less than 3.9 μs at a 20 wt% dopant concentration. Highly efficient solution-processable organic light-emitting devices have been prepared with superior current efficiencies of up to 51.6 cd A-1 and external quantum efficiencies of up to 15.3%. Notably, triplet-triplet annihilation has been significantly reduced, as exemplified by a very small efficiency roll-off of ∼1% at a practical brightness of 500 cd m-2.

A new class of tridentate ligand-containing cyclometalated gold(III) complexes featuring dendritic alkynyl ligands with carbazole moieties as dendrons and peripheral groups has been synthesized up to the third generation. High-performance solution-processable organic light-emitting devices (OLEDs) with maximum current efficiency of up to 23.7 cd A–1 and external quantum efficiency of up to 6.9% have been realized by a simple spin-coating technique. With the incorporation of bulky carbazole moieties to form higher generation dendrimers, the undesirable excimeric emission could be effectively reduced, allowing the fine-tuning of the emission color toward the blue region. This represents the first successful demonstration of sky-blue-emitting alkynylgold(III) complexes and its application in solution-processable OLEDs.

A new class of gold(III) complexes with saturated poly(benzyl ether) dendrons has been synthesized, characterized, and applied as phosphorescent dopants in the fabrication of solution-processable organic light-emitting devices (OLEDs). The incorporation of the poly(benzyl ether) dendron into the cyclometalated gold(III) center can effectively perturb the packing of the molecules and minimizes the intermolecular interactions for suppressing excimeric emission. In addition, blue-green-emitting OLEDs can be realized, representing the first example of a blue-green-emitting device based on saturated dendrimer containing alkynylgold(III) complexes. Taking advantage of the diverse and well-developed synthetic routes for saturated dendrons, this work provides a simple means to develop a new class of gold(III) complexes emitting in the blue region.

Bridges can be categorised by span lengths, such as short-span, medium-span, long-span and super-long-span and also by type, such as girder bridges, arch bridges, cable-stayed bridges and suspension bridges. This paper studies how long a span for each of these four types of bridges can be.

The design process of a bridge can be divided into four basic stages: conceptual design, preliminary design, detailed design and construction design. The purpose of the conceptual design is to come up with various feasible bridge schemes and to decide on one or more final concepts for further consideration. The purpose of the preliminary design is to select the best scheme from these proposed concepts and then to ascertain the feasibility of the selected concept and finally to refine its cost estimates. The purpose of the detailed design is to finalise all the details of the bridge structure so that the document is sufficient for tendering and construction. Finally, the purpose of the construction design is to provide step-by-step procedures for the building of the bridge.

Sky-blue-emitting arylgold(iii) complexes have been synthesized for OLEDs with EQEs of up to 11.3%., A new class of sky-blue-emitting arylgold(iii) complexes containing tridentate bis-cyclometalating ligands derived from 2,6-diphenylpyridine (C^N^C) has been successfully designed and synthesized. By systematically varying the electron-withdrawing groups from cyano, fluoro, and trifluoromethyl to trifluoromethoxy groups on the phenyl ring of the tridentate C^N^C ligands, the emission maxima of these complexes have been significantly blue-shifted from 492 nm to 466 nm in dichloromethane solution. In addition, the higher excited state distortion with respect to the ground state associated with the multiple fluoro substitutions at the tridentate ligand has been successfully reduced by the employment of trifluoromethyl and trifluoromethoxy groups, as revealed by the Huang-Rhys factor. Taking advantage of their high photoluminescence quantum yields of up to 43% in the solid-state MCP thin-films, high performance solution-processable and vacuum-deposited organic light-emitting devices with external quantum efficiencies of up to 5.3% and 11.3%, respectively, have been realized. This work represents the first demonstration of sky-blue-emitting gold(iii) complexes with an x chromaticity coordinate of