Efficient inverted quantum-dot (QD) light-emitting diodes (LEDs) are demonstrated by using 15% Mg doped ZnO (ZnMgO) as an interfacial modification layer. By doping Mg into ZnO, the conduction band level, the density of oxygen vacancies and the conductivity of the ZnO can be tuned. To suppress excess electron injection, a 13 nm ZnMgO interlayer with a relatively higher conduction band edge and lower conductivity is inserted between the ZnO electron transport layer and QD light-emitting layer, which improves the balance of charge injection and blocks the non-radiative pathway. Moreover, according to the electrical and optical studies of devices and materials, quenching sites at the ZnO surface are effectively reduced by Mg-doping. Therefore exciton quenching induced by ZnO nanoparticles is largely suppressed by capping ZnO with ZnMgO. Consequently, the red QLEDs with a ZnMgO interfacial modification layer exhibit superior performance with a maximum current efficiency of 18.69 cd A and a peak external quantum efficiency of 13.57%, which are about 1.72- and 1.74-fold higher than 10.88 cd A and 7.81% of the devices without ZnMgO. Similar improvements are also achieved in green QLEDs. Our results indicate that ZnMgO can serve as an effective interfacial modification layer for suppressing exciton quenching and improving the charge balance of the devices.

Perovskite solar cells (PSCs) are one of the promising photovoltaic technologies for solar electricity generation. NiOx is an inorganic p‐type semiconductor widely used to address the stability issue of PSCs. Although high efficiency is obtained for the devices employing NiOx as the hole transport layer, the fabrication methods have yet to be demonstrated for industrially relevant manufacturing of large‐area and high‐performance devices. Here, it is shown that these requirements can be satisfied by using the magnetron sputtering, which is well established in the industry. The limitations of low fill factor and short‐circuit current commonly observed in sputtered NiOx‐derived PSCs can be overcome through magnesium doping and low oxygen partial pressure deposition. The fabricated PSCs show a high power conversion efficiency of up to 18.5%, along with negligible hysteresis, improved ambient stability, and high reproducibility. In addition, good uniformity is also demonstrated over an area of 100 cm2. The simple and well‐established approach constitutes a reliable and scale method paving the way for the commercialization of PSCs.

Deep blue emitters are crucial for full color displays and organic white lighting. Thanks to the research efforts by scientists, many efficient light emitters with aggregation-induced emission (AIE) characteristics have been synthesized and found promising applications in organic lightemitting diodes (OLEDs). However, few AIE emitters with deep blue emissions and excellent electroluminescence (EL) performance have been reported. The contribution here reports a simple but successful molecular design strategy for synthesizing efficient solid-state emitters for nondoped OLEDs with both deep blue and white emissions. This strategy utilizes triphenylethene, a weakly conjugated AIE luminogen, as building block for constructing deep blue emitter, involving no complicated control of emission color through adjustment of the steric hindrance of chromophores, and enables a wide selection of partnered functional units. The synthesized AIE luminogen, abbreviated as BTPE-PI, is thermally stable and exhibits high fluorescence quantum efficiency as well as good charge injection capability in the solid state. Nondoped deep blue OLED fabricated from BTPE-PI shows a very high external quantum efficiency of 4.4% with a small roll-off, whose performance is the best among deep blue AIE materials reported so far. An efficient white OLED with Commission Internationale de l'Eclairage (CIE) coordinates of (0.33, 0.33) at theoretical white point was first achieved by using AIE luminogen BTPE-PI as deep blue emitter. Such molecular design strategy opens a new avenue in the development of efficient solid-state deep blue emitters for nondoped OLED applications.

In this paper, by merging the hole-dominated triphenylamine (TPA) and tetraphenylethene (TPE) moieties together with different linkage positions, four derivatives of 1,2-bis[4 0-(diphenylamino)biphenyl-4-yl]-1,2diphenylethene (2TPATPE) were successfully synthesized with confirmed structures, and their thermal, optical and electronic properties were fully investigated. Thanks to the introduction of the meta-linkage mode on the TPE core, their p-conjugation length could be effectively restricted to ensure blue emission. The non-doped OLEDs based on these four emitters exhibit blue emissions from 443-466 nm, largely blue-shifted with respect to the green emission of 2TPATPE (514 nm). Meanwhile, good electroluminescence efficiencies with L max , h C,max , and h P,max of up to 8160 cd m À2 , 3.79 cd A À1 , and 2.94 Im W À1 respectively, have also been obtained, further validating our rational design of blue AIE fluorophores.

The unique features of solution-processed quantum dots (QDs) including emission tunability in the visible range, high-quality saturated color and outstanding intrinsic stability in environment are highly desired in various application fields. Especially, for the preparation of wide color gamut displays, QDs with high photoluminescence quantum yield are deemed as the optimal fluorescent emitter that has been utilized in the backlight for liquid crystal display. Nevertheless, the commercialization of electrically driven self-emissive quantum dot lightemitting diode (QLED) display is the ultimate target due to its merits of high contrast, slim configuration and compatibility with flexible substrate. Through the great efforts devoted to material engineering and device configuration, astonishing progresses have been made in device performance, giving the QLED technology a great chance to compete with other counterparts for next-generation displays. In this review, we retrospect the development roadmap of QLED technology and introduce the essential principles in the QLED devices. Moreover, we discuss the key factors that affect the QLED efficiency and lifetime. Finally, the advances in device architectures and pixel patterning are also summarized.

In this work, two tailored luminogens (TPE-NB and TPE-PNPB) consisting of tetraphenylethene (TPE), diphenylamino, and dimesitylboryl as a π-conjugated linkage, electron donor, and electron acceptor, respectively, are synthesized and characterized. Their thermal stabilities, photophysical properties, solvachromism, fluorescence decays, electronic structures, electrochemical behaviors, and electroluminescence (EL) properties are investigated systematically, and the impacts of electron donor-acceptor (D-A) interaction on optoelectronic properties are discussed. Due to the presence of a TPE unit, both luminogens show aggregation-induced emission, but strong D-A interaction causes a decrease in emission efficiency and red-shifts in photoluminescence and EL emissions. The luminogen, TPE-PNPB, with a weak D-A interaction fluoresces strongly in solid film with a high fluorescence quantum yield of 94%. The trilayer OLED [ITO/NPB (60 nm)/TPE-PNPB (20 nm)/TPBi (40 nm)/LiF (1 nm)/Al (100 nm)] utilizing TPE-PNPB as a light emitter shows a peak luminance of 49 993 cd m(-2) and high EL efficiencies up to 15.7 cd A(-1), 12.9 lm W(-1), and 5.12%. The bilayer OLED [ITO/TPE-PNPB (80 nm)/TPBi (40 nm)/LiF (1 nm)/Al (100 nm)] adopting TPE-PNPB as a light emitter and hole transporter simultaneously affords even better EL efficiencies of 16.2 cd A(-1), 14.4 lm W(-1), and 5.35% in ambient air, revealing that TPE-PNPB is an eximious p-type light emitter.

Replacement of phenyl ring(s) in tetraphenylethene by naphthalene ring(s) generates a series of new luminogens with aggregation-induced emission (AIE) characteristics, demonstrating that bulky naphthalene rings can serve as a rotor to construct AIE luminogens.

2,3,4,5‐Tetraphenylsiloles are excellent solid‐state light emitters featured aggregation‐induced emission (AIE) characteristics, but those that can efficiently function as both light‐emitting and electron‐transporting layers in one organic light‐emitting diode (OLED) are much rare. To address this issue, herein, three tailored n‐type light emitters comprised of 2,3,4,5‐tetraphenylsilole and dimesitylboryl functional groups are designed and synthesized. The new siloles are fully characterized by standard spectroscopic and crystallographic methods with satisfactory results. Their thermal stabilities, electronic structures, photophysical properties, electrochemical behaviors and applications in OLEDs are investigated. These new siloles exhibit AIE characteristics with high emission efficiencies in solid films, and possess lower LUMO energy levels than their parents, 2,3,4,5‐tetraphenylsiloles. The double‐layer OLEDs [ITO/NPB (60 nm)/silole (60 nm)/LiF (1 nm)/Al (100 nm)] fabricated by adopting the new siloles as both light emitter and electron transporter afford excellent performances, with high electroluminescence efficiencies up to 13.9 cd A–1, 4.35% and 11.6 lm W–1, which are increased greatly relative to those attained from the triple‐layer devices with an additional electron‐transporting layer. These results demonstrate effective access to n‐type solid‐state emissive materials with practical utility.