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Titanium-doped InZnO (TiIZO) thin-film transistors (TFTs) with different doping concentrations were successfully fabricated using plasma-enhanced atomic layer deposition (PEALD). Specifically, TiIZO TFTs with Ti cation doping concentration of 0.5% using tetra (dimethylamino) titanium (TDMATi) exhibited a high field-effect mobility of 51.22 cm2/Vs and a small subthreshold swing (SS) of 0.24 V/decade. Furthermore, compared to undoped IZO TFTs, TiIZO TFTs exhibited enhanced bias stability under positive and negative temperature bias stress. This improvement is attributed to the appropriate Ti doping concentration, which suppresses impurity oxygen defects, reduces the trap density at the insulator/channel interface, and introduces additional charge carriers.

A direct soft imprint lithography was proposed to realize the direct fabrication of residue-free, well-shaped functional patterns through a single step. This imprint method requires only a simply prepared isopropanol-treated polydimethylsiloxane (PDMS) stamp without any additional resists. Residue-free Ag patterns were successfully fabricated on different substrates by directly imprinting the Ag ink with the isopropanol-treated PDMS stamp. Furthermore, the coffee-ring effect of the imprinting Ag patterns can be eliminated by optimizing the imprinting time, isopropanol-treating time, and imprinting temperatures. Studies show that the residual Ag ink in the contact region can be absorbed by the isopropanol-treated PDMS stamp due to the “like dissolves like” principle. Finally, this method was employed to fabricate the Ag electrodes for the thin-film transistors, attaining a mobility of ∼8 cm2V–1s–1, which is comparable to those with vacuum-processed electrodes. This process provides a simple, low-cost, residue-free, coffee-ring-free, and fast patterning method in the field of microelectronics.

In this study, thin-film transistors (TFTs) with amorphous indium-zinc oxide (IZO) channel were fabricated by plasma-enhanced atomic layer deposition (PEALD). By optimizing the cyclic ratio of laminated ZnO/In2O3, the IZO-TFTs demonstrated a high field-effect channel mobility ( $\mu $ FE) of 42.19 cm2/V s, a threshold voltage ( ${V} _{\text {th}}$ ) of -0.63 V, and a subthreshold swing (SS) of 0.27 V/decade. Moreover, these TFTs exhibited excellent stability during the accelerated test of positive bias temperature stress (PBTS) and negative bias temperature stress (NBTS). This enhanced stability can be attributed to the reduction of defect states achieved through the structural design of the stacked subsequence.

This article presents a comprehensive investigation of the abnormal positive shift phenomenon of the threshold voltage ( ${V}_{\text {th}}$ ) in praseodymium (Pr)-doped indium zinc oxide thin-film transistors (PrIZO-TFTs) under negative bias illumination temperature stress (NBITS). It has been demonstrated that the presence of acceptor-like defects near the conduction band minimum (CBM) increases with Pr doping, leading to a lower carrier concentration. These TFTs also exhibit significant suppression of light-induced instability by reducing oxygen vacancies (Vo). However, our examination of NBITS revealed an abnormal positive shift of ${V}_{\text {th}}$ in PrIZO-TFTs. Further analysis uncovered that the positive shift of ${V}_{\text {th}}$ primarily occurred under 2.17-eV illumination, which aligns with the defect position of 2.30 eV from the conduction band in oxygen vacancy theory. We propose the “dipole theory” to explain this contradictory positive shift, suggesting that Pr $^{{4}+}$ gains two electrons from Vo under illumination. This results in the generation of a dipole composed of negatively charged Pr $^{{3}+}$ and positively charged Vo $^{{2}+}$ , leading to lattice distortion under negative bias. Consequently, positive charges accumulate near the gate insulator (GI), resulting in a positive ${V}_{\text {th}}$ shift.

The amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) are of great interest due to their high mobility, excellent homogeneity, and low processing temperature. With energy conservation and flexible electronics emerging, further reducing post-processing temperatures has become a primary concern. $\text{O}_{{2}}$ plasma treatment has received much attention because it can supply oxygen atoms directly and enhance the performance of AOS thin films at low temperatures. In this study, we provide a combined post-treatment incorporating low-temperature annealing and $\text{O}_{{2}}$ plasma treatment to improve the performance of praseodymium-doped indium zinc oxide (PrIZO) thin films and TFTs. With the increase of $\text{O}_{{2}}$ plasma treatment power, the density of PrIZO thin films first increases and then decreases, reaching a maximum of 6.3 $\text{g}\cdot $ cm $^{-{3}}$ at 40 W. With the increasing $\text{O}_{{2}}$ plasma treatment power, the surface roughness of PrIZO thin films first decreases and then increases, achieving a minimum of 0.49 nm at 40 W. The optimized PrIZO TFT exhibits good electric performance with a $\mu _{\text {sat}}$ of 17.9 cm $^{{2}} \cdot \text{V}^{-{1}} \cdot \text{s}^{-{1}}$ , a subthreshold swing (SS) of 0.40 $\text{V}\cdot $ dec $^{-1}$ , a threshold voltage ( ${V}_{\text {TH}}$ ) of −1.1 V, and an ${I}_{ \mathrm{\scriptscriptstyle ON}}/{I}_{ \mathrm{\scriptscriptstyle OFF}}$ ratio of 7.4 $\times \,\,10^{{7}}$ ultimately. A novel combined posttreatment incorporating low-temperature annealing and $\text{O}_{\mathbf {2}}$ plasma treatment is proposed and proved promising.

In this work, a novel thin film transistor (TFT) structure named ASD was prepared, which means active layer bottom‐contact with source/drain(SD) layer. ASD device use the first light shield metal layer served as SD electrode simultaneously, which can reduce 2‐count‐mask array process compared with traditional top gate (TG) device. The mobility and subthreshold swing of the ASD a‐IGZO TFT device can reach 14 cm2/Vs and 0.18 V/dec, respectively. The PBTS and NBTIS are within 0.5V through process optimization. In addition, a 7.1 inch Micro‐LED display used ASD TFT backplane has demonstrated, and Finally, the Micro‐LED panel shows +0.7V Vth shift after the high temperature and high humidity operation (HTHHO) 500h reliability test.

Perovskite materials can realize the transition from green light to full-visible light spectrum by halogen anion exchange. Here, we designed an in-situsolid-phase anion-exchange method combined with inkjet printing to achieve full-color perovskite quantum dot light-emitting diodes (PeQD-LEDs). It was revealed that, in addition to the concentration, the anion-exchange rate was affected by the dielectric constant of the anion-exchange medium solvent. Without destroying the PeQD film, the higher the dielectric constant of the solvent, the faster the reaction rate. And at the same time, the solvent with higher dielectric constant will cause more defects, so the morphology, structure and properties of the perovskite films varied with solvents. The chain length of amine salts in anion-exchange medium solute also played a key role in the stability of electroluminescence spectra. The obtained blue-light devices had a maximum EQE of 4.6% at 481 nm and 6.6% at 493 nm prepared by spin-coating. For inkjet printing, instead of printing red-, green- and blue-luminescent materials, we printed halogen-containing materials to achieve the in-situsolid-phase anion-exchange with underlying PeQDs, and the inkjet-printed full-color device showed the current efficiency of 0.78 cd A−1. The method to achieve full-color devices by inkjet-printing halogen-containing materials can not only simplify the process, but also broaden the range of material selection, making the ink preparation more selective.

Inspired by some previous surveys, we obtained significant electrochromic properties by hydrothermal synthesis using a solution of Iron (II) Chloride, Ammonium Metatungstate, Sodium Hydroxide and Hydrochloric Acid. The respond time of the electrochromic device was accelerated by iron (II) chloride that the coloring time was 6.5s while the bleaching time was 11.5s at the molar concentration ratio of 1:3.5 between ammonium metatungstate and iron (II) chloride, PH=2.5. Meanwhile the device had a significant optical modulation of 65% with air serving as a blank. Influenced by the acidic environment, the aqueous solution will occur hydrogen evolution reaction (HER) which dramatically deteriorated the stable of active layer over a long period of cycling. Here we innovatively apply a hydrogen bond acceptor, dimethyl sulfoxide (DMSO) to the formulation, the open circuit voltage of HER can be increased as well as the overpotential through restricting all hydrogen atoms of the water molecules in the DMSO‐H2O H‐bond network which can achieve the effect of maintaining a steady cycle of over 800 cycles.

Microelectronic devices are developing rapidly in portability, wearability, and implantability. This puts forward an urgent requirement for the delicate deposition process of materials. Electrohydrodynamic printing has attracted academic and industrial attention in preparing ultrahigh-density microelectronic devices as a new noncontact, direct graphic, and low-loss thin film deposition process. In this work, a printed graphene with narrow line width is realized by combining the electrohydrodynamic printing and surface treatment. The line width of printed graphene on the hydrophobic treatment surface reduced from 80 to 28 μm. The resistivity decreased from 0.949 to 0.263 Ω·mm. Unexpectedly, hydrophobic treatment can effectively induce random stacking of electrohydrodynamic printed graphene, which avoids parallel stacking and agglomeration of graphene sheets. The performance of printed graphene is thus effectively improved. After optimization, a graphene planar supercapacitor with a printed line width of 28 μm is successfully obtained. Its capacitance can reach 5.39 mF/cm2at 50 mV/s, which is twice higher than that of the untreated devices. The device maintains 84.7% capacitance after 5000 cycles. This work provides a reference for preparing microelectronic devices by ultrahigh precision printing and a new direction for optimizing two-dimensional material properties through stacking adjustment.

In this study, the explanation of the enhanced negative-bias-illumination-temperature stress stability (NBITS) of indium-zinc-oxide thin-film transistors (IZO TFTs) under terbium (Tb) doping is addressed. The acquired Tb-IZO TFTs exhibit enhanced stability compared with pristine device ( $\Delta {V}_{\text {th}}$ after NBITS decreased from−4.1 to −0.6 V). Hall measurements, X-ray photoelectron spectroscopy, and microwave photoconductivity decay were used to analyze the impact of Tb doping on the characteristics of metal–oxide–semiconductor films. It is believed that Tb-induced shallow defects may serve as the recombination centers for capturing photo-generated electrons, which is an essential complement to the trap-assisted model. The optimized Tb content is considered to be 3.21 at.%, with a mobility of 20.0 cm2/ $\text{V}\cdot \text{s}$ , ${I}_{ \mathrm{\scriptscriptstyle ON}}/{I}_{ \mathrm{\scriptscriptstyle OFF}}$ ratio of $10^{{9}}$ , and an NBITS of −0.8 V.

The realization of electrically pumped organic semiconductor lasers needs to suppress singlet–triplet annihilation (STA) as much as possible. Generally, organic gain medium materials suffer extensive loss of singlet excitons through STA, resulting in extremely high lasing threshold current density (Jth) on the order of 10–100 kA cm–2. Herein, we study the lasing and electroluminescence (EL) properties of a new organic gain material, named PIO, with low STA. As shown, it exhibits remarkable optical gain and EL performance. A low lasing threshold of 0.47 mJ cm–2and a high Q-factor of 6000 are well obtained in the microring resonator. In pulse-driven organic light emitting diodes (OLEDs), a high current density of 112.4 A cm–2is achieved. Furthermore, a dynamical model is used to analysis exciton dynamics, gain behaviors and singlet exciton loss channels under electrical excitation. It is found that the rate of STA (kST) is at least lower than 1 × 10–10cm3s–1to realize lasing emission with Jthbelow the order of 10 kA cm–2. The kSTof the doped PIO is determined to be 6.6 × 10–12cm3s–1. Therefore, it can be predicted that the lasing threshold Jthof PIO is about 1.20 kA cm–2.

In this work, high‐mobility oxide backing‐plate with pulse‐hybrid‐modulation (PHM) driving circuit has been well applied in CSOT G4.5 production line. The self‐aligned top‐gate (SATG) thin film transistor (TFT) exhibits linear mobility over 30 cm2V‐1s‐1, excellent Vthuniformity 0.3±0.2V and PBTS/NBTIS <1.5 V/h. The PHM driving circuit significantly improves the low‐gray uniformity and the color gamut shift of Micro‐LED (MLED) under low‐current density. In addition, a 19 inch spliced MLED panel has been demonstrated, in which color gamut >120% NTSC, pixel pitch 0.4 mm, contrast ratio >1000000:1, invisible border and splicer.

Metal oxide semiconductors (MOS) have shown great application potential as the active layer of thin film transistors (TFTs). However, MOTFTs usually require an annealing process(≥300°C), which is not conducive to its application in flexible substrates. Here, we establish a Room‐Temperature manufacturing strategy of TFT, which consist of a Nd:AIZO/Al2O3bilayer structure as the active layer. The Nd:AIZO/Al2O3bilayer TFTs without further thermal annealing processing show reasonable device characteristics with mobility(µsat) of 28.7 cm2V‐1s‐1, an Ion/Ioffratio of 108, a threshold voltage(Vth) of 0.2 V, and a subthreshold swing(SS) of 0.25 V/decade. The room‐ temperature preparation of Nd:AIZO/Al2O3bilayer TFT is compatible with low‐cost flexible substrates, which is anticipated in the application of large‐size flexible electronic devices, especially of the "green" flexible display area.

Artificial synaptic devices with high transconductance, low energy consumption and good stretchability are important for efficient and energy-friendly neuromorphic computations in the field of bionics. Here, we propose a stretchable substrate inspired by wrinkled surface of human skin, and achieve a low energy operation stretchable synaptic transistor (SST) based on n-type oxide semiconductor. The SSTs exhibit excellent performance, including high mobility (4.08 cm2V−1s−1) and high transconductance (over 12 mS) under ultra-low operation voltage of 0.1 V. They can stand against multi-directional stretching of 10 % and up to 400 stretch/release cycles. In addition, the n-type SSTs achieve synaptic performance at ultra-low energy consumption (0.36 fJ) with dual-mode operation characteristics of excitatory and inhibitory behaviors. Under tensile strain, they exhibit typical synaptic behavior, including short-term/long-term plasticity, pair pulse facilitation, spike voltage/frequency/duration/number-dependent plasticity. More importantly, the SSTs exhibit excellent “learning-forgetting-relearning” feature and good stability under potentiation-depression cycle test, showcasing tremendous potential in brain-inspired computation. Finally, a high recognition accuracy (89.6 %) is attained simulated by handwritten digital datasets. To the best of our knowledge, this is the first stretchable synaptic transistor with oxide semiconductors, and it is also a major breakthrough in n-type stretchable synaptic transistors for high-speed and low-energy calculation and storage for brain-inspired computing.

Organic LEDs that emit light in the short-wavelength infrared (SWIR) region, which spans the 1–2 μm region, are attractive for applications in biosensors, biomedical imaging and spectroscopy, and surveillance. However, fabrication of such devices with high radiance has not yet been achieved owing to an intrinsic limitation imposed by the energy-gap law, which leads to extremely low emission efficiencies. Here, we report that acceptor–donor–acceptor-type molecules with high coplanarity, rigid π-conjugated backbones, an extremely small reorganization energy and an electron–phonon coupling factor are capable of simultaneously providing a strongly suppressed non-radiative recombination rate and a high operation stability at high current density. We achieve electrically driven SWIR organic LEDs with an irradiance of up to 3.9 mW cm−2(corresponding to 7% of direct sunlight infrared irradiance). These findings should open a wide avenue to a new class of organic SWIR light sources for a broad range of applications.

Thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have been demonstrated in applications such as displays and solid-state lightings. However, weak stability and inefficient emission of blue TADF OLEDs are two key bottlenecks limiting the development of solution processable displays and white light sources. This work presents a solution-processed OLED using a blue-emitting TADF small molecule bis[4-(9,9-dimethyl-9,10-dihydroacridine) phenyl]sulfone (DMAC-DPS) as an emitter. We comparatively investigated the effects of single host poly(N-vinylcarbazole) (PVK) and a co-host of 60% PVK and 30% 2,2′-(1,3-phenylene)-bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole] (OXD-7) on the device performance (the last 10% is emitter DMAC-DPS). The co-host device shows lower turn-on voltage, similar maximum luminance, and much slower external quantum efficiency (EQE) rolloff. In other words, device stability improved by doping OXD-7 into PVK, and the device impedance simultaneously and significantly reduced from 8.6 × 103to 4.2 × 103Ω at 1000 Hz. Finally, the electroluminescent stability of the co-host device was significantly enhanced by adjusting the annealing temperature.

The work presents a novel pixel circuit which breaks the constraint that the PWM driving method combined with internal compensating is unable to achieve a high-bit display. By adding another TFT to transform the equal division of PWM to unequally divided subfields, the bit of a 240 Hz 10-row panel is improved from 3 bits to 8 bits, which is a great breakthrough for bits improving in the fields of PWM driving and internal compensating. Furthermore, simulation results of the original 6T1C circuit and revised 7T1C circuit demonstrate that the current error ratio is almost the same, indicating that this revising 7T1C circuit is suitable for bits improving without sacrificing the circuit margin.

The inferior light extraction efficiency (LEE), which is generally less than 20%, based on optical modeling, and the difficulty in achieving white emission are the two main challenges in the metal-halide-perovskite light-emitting diode (PeLED) field. Herein, we report a simple and efficient approach to construct high-performance white PeLEDs with much-enhanced LEE by coupling a blue PeLED with a layer of red perovskite nanocrystal (PeNC) down-converter through a rationally designed multilayer semitransparent electrode (LiF/Al/Ag/LiF). The red PeNC layer allows the extraction of the trapped waveguide mode and surface plasmon polariton mode in a blue PeLED and converts them to red emission, resulting in over 50% LEE improvement. Simultaneously, the complementary emission spectrum of blue photons and down-converting red photons contributes to a white PeLED with a high external quantum efficiency and luminance of more than 12% and approximately 2,000 cd m−2, respectively, which represent state-of-the-art results in this field.

Tungsten oxide (WO3) electrochromic devices have attracted a lot of interest in the energy conservation field and have shown a preliminary application potential in the market. However, it is difficult to quantitatively direct experiments with the existing electrochromic theoretical models, which can restrict the further development of electrochromism. Here, an electrochromic physical simulation model of WO3films was built to solve the above problem. Experimentally, the actual electrochromic kinetics of WO3in the LiClO4/propylene carbonate electrolyte was determined as a continuous electron-transfer process by cyclic voltammetry measurement and X-ray photoelectron spectroscopy analysis. Theoretically, the continuous electron-transfer process, Li+-ion diffusion process, and the transmittance change process were described by a modified Butler–Volmer equation, Fick’s law, and charge versus coloration efficiency/bleaching efficiency coupling equation, respectively. The comparisons between theoretical and experimental data were conducted to verify this model. The shape of the simulated current curves was basically consistent with that of experiments. Besides, the difference of transmittance between the simulation and experiments was less than 8%. The difference between theory and experiment was attributed to the influence of the electric double layer and the actual reaction interface. The success of the simulation was attributed to the accurate description of the electrochromic process by continuous electron-transfer kinetics. This model can be applied in the research of electrochromic mechanisms, experimental result prediction, and novel device development due to its clear physical nature.

Drop-on-demand printing is a noncontact direct patterning and rapid manufacturing printing technology which shows considerable potential in future display manufacturing. Metal oxides are an important kind of functional material in thin-film transistors, which are the core component of active matrix display technology, and thus printing a high-quality metal oxide functional layer is of great importance. In this feature article, we focused on the current progress in one of the foundations of drop-on-demand printing technology—the ink system. We explained the basic principles of a metal oxide ink system for printed electronics and summarized the applications of several kinds of ink systems in thin film transistor printing. Meanwhile, we also summed up problems that printed thin film transistors are facing as well as the corresponding solutions from the aspect of ink systems.

A super high‐resolution OLED display has been fabricated via electrohydrodynamic printing. The solvent properties dominate the ink's printability and printing stability. By using a 1.5 µm diameter nozzle, the line widths of printed polymers are reduced to less than 2 µm. A green‐color passive matrix display with a resolution of 2115 PP1 (pixel per inch) has been successfully realized.

For light-emitting polymers with a deep highest occupied molecular orbital energy level used for polymer light-emitting diodes (PLEDs), the hole injection barrier and hole transport of the anode buffer layer are of vital importance for optimizing electroluminescent performance. In this study, high-work-function hole injection layers with nanotextures were achieved by modifying poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) with a perfluorinated ionomer (PFI) and n-butyl alcohol and were used to achieve a single-layer device without a hole transport layer. With such an interlayer, the PLEDs based on PPF-SO25 exhibit remarkable current efficiency over 13.0 cd A–1, which significantly outperform the devices with regular PEDOT:PSS. To our knowledge, this performance is among the best reported for single-layer blue PLEDs. The bias-dependent capacitance curves of these PLEDs suggest a nonuniform surface distribution of PFI. Our findings show that the PFI-modified PEDOT:PSS not only operates as a high-work-function hole injection layer to facilitate hole injection but also as a potential inner scattering medium for light extraction.

In electrochemistry, the carbazole is generally coupled to dimer but not to polymer. This work has reported that organic electropolymerization (OEP) of 4,4′,4″-tri(N-carbazolyl)triphenylamine (TCTA) would form a high cross-linked carbazole polymer by its high activity/reversibility and a synchronous viscosity control. It has significantly improved the OEP film quality of both hole-transporting and electroluminescent layers in organic light-emitting diodes. As a result, the conductivity and power efficiency of the organic light-emitting diodes with TCTA are eight and four times of that without TCTA. A prototype display device with a 1.7 in. monochrome passive matrix of 58 ppi under the driving chip is successfully fabricated with accurate pixel size and uniform electroluminescence, which shows a great potential of OEP in the electroluminescent application.

In this paper, the effect of deep ultraviolet (UV) laser on physical and electrical properties of amorphous Silicon‐doped tin oxide (amorphous Si‐Sn‐O, a‐STO) thin films were studied. Surface morphology, thickness, crystallinity, and optical band gap of a‐STO thin films treated by laser were investigated. Results showed that the decrease of thickness and surface roughness of a‐STO thin films after deep UV laser treatment, and the films maintained an amorphous structure, which implied that the quality of a‐STO thin films were improved. The peak position of oxygen vacancy binding energy became lower; this is caused by an increase in oxygen vacancies resulting in a decrease in coordination number. And the oxygen vacancy content of the a‐STO thin films was increased after deep UV laser treatment. In addition, the optical band gap of a‐STO films was broaden after the deep UV laser treatment. It exploits a new application of deep UV laser in oxide semiconductor. Deep UV laser treatment can increase the oxygen vacancy concentration of the silicon doped tin oxide (STO) thin film, thereby improving the electrical properties of STO thin film. Deep UV laser treatment can widen the optical band gap of STO thin film. Laser treatment leads to a decrease in the atomic coordination number in the a‐STO film.

Light-emitting field-effect transistors (LETs) have drawn much attention for their special capability of combining switching and electroluminescence capacity in a single device. Herein, we report a colour-saturated, high-efficiency red quantum-dot hybrid light-emitting field-effect transistor (QD-HLET) with a solution-processed InScO/ZnO-nanoparticle heterojunction channel layer and a deep-level organic hole transport layer (HLT). The red QD-HLET exhibits a field-effect mobility of 3.1 cm2V−1s−1with an on/off ratio of ∼105, a maximum brightness of 145 000 cd m−2with a peak external quantum efficiency (EQE) of 22.8% and low efficiency roll-off (an EQE of 17.0% at a brightness of 100 000 cd m−2). In addition, the operating stability of the HLET is investigated by monitoring the time-dependent change in the brightness of the QD-HLET under various VGS, while an operational lifetime of more than 153 000 hours at 100 cd m−2is achieved. A comprehensive study on the electrical and optical characteristics of the red QD-HLET under different operation modes is conducted, and an operation model is proposed.

Integrating biodegradable cellulose nanopaper into oxide thin-film transistors (TFTs) for next generation flexible and green flat panel displays has attracted great interest because it offers a viable solution to address the rapid increase of electronic waste that poses a growing ecological problem. However, a compromise between device performance and thermal annealing remains an obstacle for achieving high-performance nanopaper TFTs. In this study, a high-performance bottom-gate IGZO/Al2O3TFT with a dual-layer channel structure was initially fabricated on a highly transparent, clear, and ultrasmooth nanopaper substrate via conventional physical vapor deposition approaches, without further thermal annealing processing. Purified nanofibrillated cellulose with a width of approximately 3.7 nm was used to prepare nanopaper with excellent optical properties (92% transparency, 0.85% transmission haze) and superior surface roughness (Rq is 1.8 nm over a 5 × 5 μm2scanning area). More significantly, a bilayer channel structure (IGZO/Al2O3) was adopted to fabricate high performance TFT on this nanopaper substrate without thermal annealing and the device exhibits a saturation mobility of 15.8 cm2/(Vs), an Ion/Ioffratio of 4.4 × 105, a threshold voltage (Vth) of −0.42 V, and a subthreshold swing (SS) of 0.66 V/dec. The room-temperature fabrication of high-performance IGZO/Al2O3TFTs on such nanopaper substrate without thermal annealing treatment brings industry a step closer to realizing inexpensive, flexible, lightweight, and green paper displays.

Praseodymium‐doped indium zinc oxide (PrIZO) has been employed as the channel layer of thin film transistors (TFTs). The TFTs with Pr doping exhibit a remarkable suppression of the light induced instability. A negligible photo‐response and remarkable enhancement in negative gate bias stress under illumination (NIBS) are achieved in the PrIZO TFTs. Meanwhile, the PrIZO TFTs show reasonable characteristics with a high field effect mobility of 26.3 cm2/Vs, SS value of 0.28V/decade, and Ion/Ioffratio of 109. A prototype of fully transparent AMOLED display is successfully fabricated to demonstrate the potential of Pr‐doping TFTs applied in transparent devices. The G4.5 target of PrIZO has been fabricated for the future mass production.

Traditional inkjet printing color quantum dot technology is to print red, green and blue quantum dot inks respectively, while perovskite material is ionic compound, and changing the halogen component can change the light color, which provides a new method for inkjet printing to realize color display. Here, we report a method for implementing blue devices by ion exchange between halogen‐containing inks and underlying perovskite quantum dot films by inkjet‐printing. This method can also be used for full‐color devices.

The structural, optical, and electrical properties of Si‐doped SnO2(STO) films were investigated in terms of their potential applications for flexible electronic devices. All STO films were amorphous with an optical transmittance of ~90%. The optical band gap was widened as the Si content increased. The Hall mobility and carrier density were improved in the SnO2with 1 wt% Si film, which was attributed to the formation of donor states. Si (1 wt%) doped SnO2thin‐film transistor exhibited a good device performance and good stability with a saturation mobility of 6.38 cm2/Vs, a large Ion/Ioffof 1.44 × 107, and a SS value of 0.77 V/decade. The device mobility of a‐STO TFTs at different bending radius maintained still at a high level. These results suggest that a‐STO thin films are promising for fabricating flexible TFTs. The structural, optical and electrical properties of Si doped SnO2(STO) films annealed at 250oC were investigated in terms of their potential applications for flexible electronic devices. Flexible STO TFTs were successfully fabricated on PI substrate, which exhibited a good device performance and good stability.

Stable radicals are challenging to prepare due to their intrinsic high reactivity. Herein, three trisphenolamine radicals were readily synthesized and exhibited unexpected thermal/electrochemical stability and semiconductor property. These three nitroxide radicals could be considered as a class of aromatized nitro groups or HNO3derivatives. The closed-shell nitro-like and open-shell nitroxide resonance structure contribute to their outstanding stability. Furthermore, the tunable ground states, extremely low band gap and p-type charge transport properties were systematically investigated. More importantly, the work presents the concept of aromatic inorganic acid radical (AIAR) and aggregation-induced radical (AIR) mechanism to understand the intrinsic structure-property relationship of these radicals. In addition, we provide a novel strategy for the design of stable and low bandgap radicals for organic electronics, magnetics, spintronics, etc.

Inkjet-printed thin-film transistors (TFTs) for active-matrix light-emitting diode display are drawing much attention for the advantages of low material waste and simple fabrication processes without vacuum deposition and photolithography steps. Herein, for the first time, solution-processed quantum-dot light-emitting diode (QLED) array displays driven with the inkjet-printed oxide TFT backplane were realized and demonstrated using a general “solvent printing” method. To suppress nanopore formation in the thick oxide films, carbon-free aqueous inks were employed for gate dielectrics. No nanopore was found in the whole 120 nm-thick gate dielectrics. However, compared to the organic inks, the aqueous inks have very low viscosity, resulting in uncontrollable ink spreading especially in transline printing. The ink easily shrinks on the low-surface-energy area and spreads on the high-surface-energy area, leading to serious uniformity problems (the upper lines even break at the top of underlying lines). To solve the problem, a “solvent printing” method was employed to form coffee-line surface-energy patterns, which were uniform without shape distortion. The surface-energy patterns can restrain the ink spreading and tune the morphology of the printed films. As a result, multilayer TFT arrays with ideal shapes were achieved. The mobilities of the printed top-gate TFTs in the backplane array were 3.13 ± 0.87 cm2V–1s–1for switching TFTs and 2.22 ± 0.38 cm2V–1s–1for driving TFTs. Finally, an active-matrix red QLED character display based on the printed oxide TFT backplane and solution-processed QLEDs was demonstrated. The “solvent printing” method opens a general route for inkjet-printed multilayer electronic devices.

We have successfully developed an ink system containing inexpensive raw materials through a simple process and have printed ZrOxdielectric film at a relatively low annealing temperature of 250 °C. The ZrOxdielectric film afforded a leakage current density of 5.4 × 10–6A/cm2at 1 MV/cm and a dielectric constant of 10 and shows a promising future for flexible electronics. The ink system shows a temperature-induced gelation behavior, and a gel network is formed when the temperature rises. A high concentration of oxide precursors is obtained near the network area through the absorption function of polymer groups, and thus oxide structure can be formed at a relatively low temperature due to the shorter diffusion path of precursor polymerization. The microstructure of the printed ZrOxfilm was investigated by high resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS), and the effect of annealing temperature on film structure was studied.

Praseodymium-doped indium zinc oxide (PrIZO) has been employed as the channel layer of thin-film transistors (TFTs). The TFTs with Pr doping exhibited a remarkable suppression of the light-induced instability. A negligible photo-response and remarkable enhancement in negative gate bias stress under illumination (NBIS) were achieved in the PrIZO-TFTs. Meanwhile, the PrIZO-TFTs showed reasonable characteristics with a high-field-effect mobility of 26.3 cm2/V s, SS value of 0.28 V/decade, and Ion/Ioffratio of 108. X-ray photoelectron spectroscopy, microwave photoconductivity decay, and photoluminescence spectra were employed to analyze the effects of the Pr concentrations on the performance of PrIZO-TFTs. We disclosed that acceptor-like trap states induced by Pr ions might lead to the suppression of photo-induced carrier in conduction band, which is a new strategy for improving illumination stability of amorphous oxide semiconductors. Finally, a prototype of fully transparent AMOLED display was successfully fabricated to demonstrate the potential of Pr-doping TFTs applied in transparent devices.

Amorphous silicon tin oxide (a‐STO) semiconductor is of increasing interest for fabricating thin film transistor. The contact properties of Mo source/drain electrode to a‐STO film subjected to different thermal annealing processes was investigated. The formation of molybdenum oxide interlayer between Mo and a‐STO film annealed in air ambient was confirmed by cross‐sectional transmission electron microscopy image, and the interlayer was formed by getting oxygen from a‐STO film in air annealing process. The formation of molybdenum oxide interlayer could provide not only an adhesive layer but also an intermediate barrier layer, and it hindered Mo atoms diffuse into a‐STO film, which would form a good quality of contact interface and facilitate the electron injection from Mo electrode into a‐STO film. We demonstrated that the molybdenum oxide interlayer was formed between Mo and amorphous silicon tin oxide film. It not only hindered the diffusion of Mo atoms, improved the quality of contact interface, but also further facilitated the electron injection.

Praseodymium-doped indium zinc oxide (PrIZO) channel materials have been fabricated by a solution process with conventional chemical precursor. The PrIZO-based thin-film transistors (TFTs) exhibited a field-effect mobility of 10.10 cm2/V s, a subthreshold swing value of 0.25 V/decade, and an Ion/Ioffratio of 108. The as-fabricated PrIZO-TFTs showed an improved device performance against positive bias temperature stress (PBTS shift of 1.97 V for 7200 s), which was evidently better than the undoped IZO-TFTs (PBTS shift of 9.52 V). This result indicates that the organic residual (−OCH3and −CH2−) in metal–oxide semiconductor, which is confirmed to be a dominant effect on the performance of PBTS, can be passivated by the rare earth of praseodymium element. The residual is intended to be oxidized with a more stable ester group with the assistant of PrOx, weakening the electron-withdrawing characteristic during the thermal bias stress.

We first verify the critical role of solvent evaporation on the resolution of inkjet printing. To confirm our hypothesis, we adjusted the evaporation rate gradient along the surface of adjacent droplets by controlling the drying microenvironment. Uneven solvent evaporation flux caused thermocapillary surface flow inward the space of micrometer-sized droplets and increase the air pressure, which prevented the neighboring droplets from coalescence. When reducing the droplet distance by the solvent evaporation-based method, a uniform profile could be obtained at the same time. This work brings us a step closer to resolving one of the critical bottlenecks to commercializing printed electronic goods.

Light-emitting field-effect transistors (LEFETs) have attained great attention due to their special characteristics of both the switching capacity and the electroluminescence capacity. However, high-performance LEFETs with high mobility, high brightness, and high efficiency have not been realized due to the difficulty in developing high electron and hole mobility materials with suitable band structures. In this paper, quantum dot hybrid LEFETs (QD-HLEFETs) combining high-luminous-efficiency quantum dots (QDs) and a solution-processed scandium-incorporated indium oxide (Sc:In2O3) semiconductor were demonstrated. The red QD-HLEFET showed high electrical and optical performance with an electron mobility of 0.8 cm2V–1s–1, a maximum brightness of 13 400 cd/m2, and a maximum external quantum efficiency of 8.7%. The high performance of the QD-HLEFET is attributed to the good energy band matching between Sc:In2O3and QDs and the balanced hole and electron injection (less exciton nonradiative recombination). In addition, incorporation of Sc into In2O3can suppress the oxygen vacancy and free carrier generation and brings about excellent current and optical modulation (the on/off current ratio is 105and the on/off brightness ratio is 106).

The thin-film transistor (TFT) driving circuit is a separate electronic component embedded within the panel itself to switch the current for each pixel in active-matrix organic light-emitting diode displays. We reported a TFT-directed dye electroplating method to fabricate pixels; this would be a new method to deposit films on prepatterned electrode for organic full-color display, where TFT driving circuit provide a switching current signal to drive and direct dye depositing on selected RGB pixels. A prototype patterned color pixel matrix was achieved, as high-quality light-emitting films with uniform morphology, pure RGB chromaticity, and stable output.

Solution-processed electroluminescent tandem white quantum-dot light-emitting diodes (TWQLEDs) have the advantages of being low-cost and high-efficiency and having a wide color gamut combined with color filters, making this a promising backlight technology for high-resolution displays. However, TWQLEDs are rarely reported due to the challenge of designing device structures and the deterioration of film morphology with component layers that can be deposited from solutions. Here, we report an interconnecting layer with the optical, electrical, and mechanical properties required for fully solution-processed TWQLED. The optimized TWQLEDs exhibit a state-of-the-art current efficiency as high as 60.4 cd/A and an extremely high external quantum efficiency of 27.3% at a luminance of 100 000 cd/m2. A high color gamut of 124% NTSC 1931 standard can be achieved when combined with commercial color filters. These results represent the highest performance for solution-processed WQLEDs, unlocking the great application potential of TWQLEDs as backlights for new-generation displays.

The formation of metal oxide interlayer is induced by pre‐annealing process in the amorphous Silicon‐Tin‐Oxide thin film transistors (a‐STO TFTs) with Mo source/drain electrodes. Cross‐sectional high‐resolution transmission electron microscopy image confirmed the formation of ~8nm MoOx interlayer. The introduction of MoOx interlayer between Mo electrodes and a‐STO improved the electron injection in a‐STO TFT. Mo adjacent to the a‐STO semiconductor gets oxygen atoms from the oxygen‐rich surface of a‐STO film to form MoOx interlayer. The self‐formed MoOx interlayer acting as an efficient interface modification layer could conduce to the stepwise internal transport barrier formation while blocking Mo atoms diffuse into a‐STO layer, which would contribute to the formation of ohmic contact between Mo and a‐STO film.

In this work, transparent thin film transistors (TFTs) using multi‐layer aluminum‐doped ZnO(AZO)/Al/AZO/Al/AZO, multi‐layer AZO/Al/AZO, single AZO source/drain (S/D) electrodes were fabricated by room temperature processes on glass substrate. The conductivity, transmittance of S/D electrode films were optimized by the insertion of two 4‐nm‐thick Al layer between the AZO layers. The resistivity of the S/D electrode films decreased from 3.34×10−3Ω·m to 6.64×10−5Ω·m and the transmittance higher than 84%. The electrical properties and optical properties of these transparent TFTs were investigated in this paper. The lower work function showed a significant effect on enhancing mobility, increasing on‐state current and output current. As a result, The TFT using the AZO/Al/AZO/Al/AZO S/D electrodes exhibit a saturation mobility of 2.64 cm2/Vs, an Ion/Ioffradio of 2.52×106, a subthreshold swing of 1.14 V/decade, and a transmittance of 71.37%. The successful high‐transparent TFTs with less Indium and less thermal annealing treatment brings industry a step closer to realizing inexpensive, flexible, transparent and green displays.