A very-high color rendering index white organic light-emitting diode(WOLED) based on a simple structure was successfully fabricated. The optimized device exhibits a maximum total efficiency of 13.1 and 5.4 lm/W at 1,0...A very-high color rendering index white organic light-emitting diode(WOLED) based on a simple structure was successfully fabricated. The optimized device exhibits a maximum total efficiency of 13.1 and 5.4 lm/W at 1,000 cd/m2. A peak color rendering index of 90 and a relatively stable color during a wide range of luminance were obtained. In addition, it was demonstrated that the 4,40,400-tri(9-carbazoyl) triphenylamine host influenced strongly the performance of this WOLED.These results may be beneficial to the design of both material and device architecture for high-performance WOLED.展开更多
Stretchable optoelectronic synapses are attractive for intelligent perception,neuromorphic computation and visual adaptation.Here,we demonstrate a highly stretchable organic optoelectronic synaptic transistor(s-OOST)w...Stretchable optoelectronic synapses are attractive for intelligent perception,neuromorphic computation and visual adaptation.Here,we demonstrate a highly stretchable organic optoelectronic synaptic transistor(s-OOST)with a transconductance up to 86 mS that can simultaneously accept modulation of electrical pulses and multi-wavelength light signals(from ultraviolet to near-infrared).The s-OOST achieved highly reliable synaptic plasticity for brain-inspired computation and retinainspired perception even under 50%tensile strain.Furthermore,the devices exibited vision-adaptive near-infrared sensing ability that was verified by single-pixel scanning imaging.Finally,the multiwavelength(365 nm-1050 nm)optical synaptic properties were investigated under the applications of imaging memory,polychromatic optical communication and information security(coded by wavelength).This research advances the capabilities of the stretchable integrated systems with vision-adaptive sensing characteristic and computing-in-memory ability.展开更多
In_(2)O_(3)-based TFTs have garnered widespread attention due to their higher mobilities than amorphous silicon.Previous studies have indicated that rare earth doping can enhance the NBIS stability of TFTs,but this of...In_(2)O_(3)-based TFTs have garnered widespread attention due to their higher mobilities than amorphous silicon.Previous studies have indicated that rare earth doping can enhance the NBIS stability of TFTs,but this often results in a decrease in mobility.To improve the mobility of TFTs while maintaining stability,we incorporated Mo and Pr into In_(2)O_(3),fabricating InPrMoO TFTs.Mo doping is believed to positively affect In_(2)O_(3)through reducing porosity and defects.Pr doping has been proposed as a potential strategy to enhance the NBIS stability of In_(2)O_(3).A nondestructiveμPCD detector was employed to characterize the local defect states of the film.X-ray photoelectron spectroscopy data demonstrate that the InPrMoO film with 0.8 mol%Mo doping has the lowest concentration of oxygen vacancies(Vo).TFTs fabricated using the InPrMoO film doped with an optimized concentration of 0.8 mol%Mo exhibit superior electrical properties(μ_(sat)=12.2 cm^(2)/V·s,V_(th)=1.6 V,I_(on)/I_(off)=2.17×10^(6),and SS=0.47 V/dec)and the minimalΔVth under NBS/PBS/NBIS=−0.65 V/0.79 V/−0.70 V.The synergistic effect of Mo and Pr doping has led to enhanced film uniformity and density,consequently improving the mobility and stability of the TFTs.To tackle the challenge of predicting optimal process parameters,a multiobjective prediction model integrating physical models and machine learning was developed.The predicted optimal parameters(0.78 mol%Mo doping,381℃ annealing)were experimentally verified,yielding<5%relative error in most film properties.The prepared TFT exhibits a mobility of 13.5 cm^(2)/V·s(10.6%improvement),an on/off current ratio of 3.82�106,and an SS of 0.40 V/dec,demonstrating superior efficiency over conventional trial-and-error methods.展开更多
Inkjet priming （IJP） is a versatile technique for realizing high-accuracy patterns in a cost-effective manner. It is considered to be one of the most promising candidates to replace the expensive thermal evaporation...Inkjet priming （IJP） is a versatile technique for realizing high-accuracy patterns in a cost-effective manner. It is considered to be one of the most promising candidates to replace the expensive thermal evaporation technique, which is hindered by the difficulty of fabricating low-cost, large electroluminescent devices, such as organic light- emitting diodes （OLEDs） and quantum dot light-emitting diodes （QLEDs）. In this invited review, we first introduce the recent progress of some printable emissive materials, including polymers, small molecules, and inorganic colloidal quantum dot emitters in OLEDs and QLEDs. Subsequently, we focus on the key factors that influence film formation. By exploring stable ink formulation, selecting print parameters, and implementing droplet deposition control, a uniform film can be obtained, which in turn improves the device performance. Finally, a series of impressive inkjet-printed OLEDs and QLEDs prototype display panels are summarized, suggesting a promising future for IJP in the fabrication of large and high-resolution flat panel displays.展开更多
Organic electron-transport materials are an essential component to boost performances and stability of organic light-emitting diodes. We present a robust organic electron-transport compound 3-(6-(3-(4,6-bis(4-biphenyl...Organic electron-transport materials are an essential component to boost performances and stability of organic light-emitting diodes. We present a robust organic electron-transport compound 3-(6-(3-(4,6-bis(4-biphenylyl)-1,3,5-triazin-2-yl)phenyl)pyridin-2-yl)phenyldiphenylphosphine oxide by facilely coupling the triphenylphosphine oxide moiety to the 2-phenyl-4,6-bis(4-biphenylyl)-1,3,5-triazine unit via a 2,6-pyridinylene linker. It is well soluble in weakly polar solvents and possesses a high Tg of 123 ℃ with an exceptional Td≈470 ℃ at 1% weight loss and deep HOMO/LUMO levels of ca.-6.45/-3.06 eV. The phosphorescent spectrum measured in solid state at 77 K reveals a notable triplet energy of 2.88 eV. n-Doping with 8-hydroxyquinolatolithium(Liq) produces the electron mobility value of 4.66×10-5–3.21×10-4 cm2 V-1 s-1@(2–5)×105 V cm-1.Moreover, the contrasting solubility of the bromo reaction intermediate and the new compound in alcoholic solvents facilitates separation. The characterizations of bottom-and top-emission green phosphorescent OLEDs involving this single Liq-doped electron-transport layer reveal long stability. In particular, the latter provides outstanding performances with 77.4 cd A–1(corresponding to an EQE of 18.7%) and 86.8 lm W–1@ca. 1000 cd m-2, based on the green emitter bis(2-phenylpyridine)(2-(4-methyl-3-phenylphenyl)pyridine)iridium(Ⅲ). Moreover, driven by a constant current for ca. 640 h, the initial luminance of 1000 cd m–2 appears almost no decay.展开更多
Two kinds of highly efficient,bright hybrid white organic light emitting diodes have been fabricated by utilizing ambipolar material 4,4-N,N-dicarbazolebiphenyl(CBP)and unipolar material N,N0-di(naphthalene-1-yl)-N,N0...Two kinds of highly efficient,bright hybrid white organic light emitting diodes have been fabricated by utilizing ambipolar material 4,4-N,N-dicarbazolebiphenyl(CBP)and unipolar material N,N0-di(naphthalene-1-yl)-N,N0-diphenyl-benzidine(NPB)as the spacer,respectively.By adjusting the thickness of spacers together with effectively utilizing combinations of exciton-harnessed orangephosphorescence/blue-fluorescence,the current efficiency of optimal device with CBP spacer and device with NPB spacer are 31.0 and 38.9 cd/A,the maximum power efficiency are 23.9 and 29.1 lm/W,the maximum brightness are 87,249 and 75,501 cd/m2,and the Commission Internationale de l’Eclairage(CIE)coordinates are(0.42,0.43)and(0.47,0.44)at a voltage of 11 V,respectively.Furthermore,systematic investigations focused on the effects of spacers on device performance have been performed.By virtue of the multifunctional spacer,energy transfer between the phosphorescent and fluorescent emitters can be avoided while the carriers still can pass through this spacer bridge,which is important to realize such high device performance.In addition,a novel concept that both ambipolar materials and unipolar materials can be the promising candidates for spacers has been proposed if the thickness of spacers with high triplet energy is optimized.展开更多
Making full-color active matrix display based on quantum dot light emitting diodes(AM-QLEDs) via ink-jet printing is attractive in display industry due to QLEDs' wide color gamut and their potential manufacturing ...Making full-color active matrix display based on quantum dot light emitting diodes(AM-QLEDs) via ink-jet printing is attractive in display industry due to QLEDs' wide color gamut and their potential manufacturing advantages of large screen size and low cost. The challenges for realizing AM-QLED display are how to achieve high quality films through ink-jet printing, multi-color patterning, electroluminescence(EL) color purity, and high efficiency. Herein, a 2-inch diagonal full-color AM-QLEDs display with pixel density of 120 pixels per inch(PPI) fabricated by ink-jet printing technique is presented. Driven by a metal oxide TFT(MOTFT) back-panel, the display exhibits a maximum brightness of 400 cd m.2, and a color gamut of 109%(NTSC 1931). The red, green, and blue(RGB) monochrome QLEDs passive matrix panels fabricated by ink-jet printing technique have a current efficiency(CE) of 2.5, 13.9, and 0.30 cd A.1, respectively. To the best of our knowledge, the efficiencies are the highest among passive matrix QLEDs panels made by ink-jet printing technique. The ink-jet printed QDs films show good thickness uniformity due to high viscosity and low volatility of the printable inks, and no cross-contamination between adjacent pixels resulting from the hydrophobic pixel defining layer.展开更多
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 ineffi-cient emission of b...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 ineffi-cient 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(Nvinylcarbazole)(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 8.6103 to 4.2103 W at 1000 Hz.Finally,the electroluminescent stability of the co-host device was significantly enhanced by adjusting the annealing temperature.展开更多
There has been an increasing demand for high-performance and cost-effective organic electron-transport materials for organic light-emitting diodes （OLEDs）. In this contribution, we present a simple compound 3-（3-（...There has been an increasing demand for high-performance and cost-effective organic electron-transport materials for organic light-emitting diodes （OLEDs）. In this contribution, we present a simple compound 3-（3-（4,6-diphenyl-l,3,5-triazin-2-yl）phenyl）-1,10-phenanthroline through the facile Pd-catalyzed coupling of a triphenyltriazine boronic ester with 3-hromo-1,10-phenanthroline. It shows a high Tg of 112℃. The ultraviolet photoelectron spectroscopy measurements reveal a deep HOMO level of -6.5 eV. The LUMO level is derived as -3.0 eV, based on the optical bandgap. The low-temperature solid-state phosphorescent spectrum gives a triplet energy of -2.36eV. n-Doping with 8-hydroxyquinolatolithium （Liq, 1：1） leads to considerably improved electron mobility of 5.2 × 10 -6 -5.8 × 10 -5 cm2 v-1 S-1 at E=（2-5） × 10 5Vcm -1, in contrast with the triarylphosphine oxide- phenantroline molecular conjugate we reported previously. It has been shown that through optimizing the device structure and hence suppressing polaron-exciton annihilation, introducing this single Liq-doped electron-transport layer could offer high-efficiency and stable phosphorescent OLEDs.展开更多
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 semicondu...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 HNO3 derivatives.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 structureproperty 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.展开更多
Tandem white organic light-emitting diodes(WOLEDs) are of great research interest since they can greatly boost the performance compared with the single-unit counterparts. However, their structures are more complicated...Tandem white organic light-emitting diodes(WOLEDs) are of great research interest since they can greatly boost the performance compared with the single-unit counterparts. However, their structures are more complicated than those of single-unit OLEDs. Besides, to achieve high performance, the doping technology is required to tandem OLEDs, particularly for tandem WOLEDs, further complicating the structures. Herein, doping-free tandem WOLEDs, for the first time, have been demonstrated. By managing an effective doping-free charge generation layer to interconnect doping-free emitting layers/charge transport layers, high-performance doping-free tandem WOLEDs have been developed. The blueyellow device accomplishes the simplified structure/short fabrication time/reduced cost/high efficiency/low efficiency roll-off/low voltage/high luminance trade-off, which cannot be achieved by previous tandem WOLEDs. Remarkably, the efficiency(81.2 cd A^(-1)) is ~2-fold higher than the highest efficiency of previous doping-free WOLEDs and even higher than those of some best doping tandem WOLEDs. The maximum luminance is 44,886 cd m^(-2), which is the highest for doping-free WOLEDs.Besides, the blue-red device can exhibit a color rendering index(CRI) of 67, which is even higher than that of some representative three-color tandem WOLEDs. Such findings may not only represent a significant step for doping-free WOLEDs, but unlock a novel avenue that doping-free tandem WOLEDs are promising to achieve the simplicity and high performance trade-off.展开更多
Flexible thin-film transistors with high current-driven capability are of great significance for the next-generation new display technology.The effect of a Cu-Cr-Zr(CCZ)copper alloy source/drain(S/D)electrode on flexi...Flexible thin-film transistors with high current-driven capability are of great significance for the next-generation new display technology.The effect of a Cu-Cr-Zr(CCZ)copper alloy source/drain(S/D)electrode on flexible amorphous neodymiumdoped indium-zinc-oxide thin-film transistors(NdIZO-TFTs)was investigated.Compared with pure copper(Cu)and aluminum(Al)S/D electrodes,the CCZ S/D electrode changes the TFT working mode from depletion mode to enhancement mode,which is ascribed to the alloy-assisted interface layer besides work function matching.X-ray photoelectron spectroscopy(XPS)depth profile analysis was conducted to examine the chemical states of the contact interface,and the result suggested that chromium(Cr)oxide and zirconium(Zr)oxide aggregate at the interface between the S/D electrode and the active layer,acting as a potential barrier against residual free electron carriers.The optimal NdIZO-TFT exhibited a desired performance with a saturation mobility(μsat)of 40.3 cm^(2)·V-1·s^(-1),an Ion/Ioff ratio of 1:24×10^(8),a subthreshold swing(SS)value of 0.12 V·decade^(-1),and a threshold voltage(Vth)of 0.83 V.This work is anticipated to provide a novel approach to the realization of highperformance flexible NdIZO-TFTs working in enhancement mode.展开更多
Perovskite quantum dots(PeQDs)are considered potential display materials due to their high color purity,high photoluminescence quantum yield(PLQY),low cost and easy film casting.In this work,a novel electroluminescenc...Perovskite quantum dots(PeQDs)are considered potential display materials due to their high color purity,high photoluminescence quantum yield(PLQY),low cost and easy film casting.In this work,a novel electroluminescence(EL)device consisting of the interface layer of long alkyl-based oleylammonium bromide(OAmBr),which passivates the surface defects of PeQDs and adjusts the carrier transport properties,was designed.The PLQY of the OAmBr/PeQD bilayer was significantly improved.A high-performance EL device with the structure of indium tin oxide/poly(3,4-ethylenedioxythiophene)polystyrene sulfonate/poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine)/OAmBr/PeQDs/2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1H benzimidazole)/LiF/Al was constructed using a spin-coating method.A peak external quantum efficiency(EQE)of 16.5%at the emission wavelength of 646 nm was obtained.Furthermore,an efficient matrix EL device was fabricated using an inkjet printing method.A high-quality PeQD matrix film was obtained by introducing small amounts of polybutene into the PeQDs to improve the printing process.The EQE reached 9.6%for the matrix device with 120 pixels per inch and the same device structure as that of the spin-coating one.展开更多
Introducing ethynylene linkages in a conjugated molecule can deepen the HOMO level, decrease the steric con- straints and better delocalize the n electrons and so on, which are beneficial for organic solar cells. Furt...Introducing ethynylene linkages in a conjugated molecule can deepen the HOMO level, decrease the steric con- straints and better delocalize the n electrons and so on, which are beneficial for organic solar cells. Furthermore, the typical method of introducing acetylene linkages by Sonogashira reactions can avoid the usage of toxic stannyl in- termediates and potentially dangerous lithiation reactions. In this study, two simple small molecules BEDPP and NEDPP are designed and synthesized, in which two diketopyrrolopyrrole units are symmetrically connected to benzene and naphthalene cores, respectively, via acetylene linkages. And the BHJ （Bulk Heterojunction） solar cells based on BEDPP and NEDPP without using solvent additive and without any post-treatment for the active layers provide us power conversion efficieneies of 1.48% and 2.31% with remarkably high open circuit voltages up to 0.90 and 0.98 V, respectively.展开更多
In this work,a sky-blue luminescent down-shifting(LDS)layer bis[(4,6-difluorophenyl)-pyridinato-N,C^(2')]c(picolinate)iridium(II)(FIrpic)was inserted between tetraphenyl dibenzoperiflanthene(DBP)and Mo0_(3)as UV-s...In this work,a sky-blue luminescent down-shifting(LDS)layer bis[(4,6-difluorophenyl)-pyridinato-N,C^(2')]c(picolinate)iridium(II)(FIrpic)was inserted between tetraphenyl dibenzoperiflanthene(DBP)and Mo0_(3)as UV-screen and sensitizer for smallmolecule DBP/C_(60)based planar heterojunction(PHJ)solar cells.With 8-nm Flrpic theshort circuit current(J_(sc))and power conversion efficiency(PCE)of the device areenhanced by 28%and 15%,respectively,probably originating from the re-absorption ofthe photons emitted from Flrpic.The V_(oc)linearly increases over 1-nm Flrpic,ascribed tothe deeper HOMO level of Flrpic than DBP,while the fill factor continuously declines from 3-to 10-nm Flrpic.The EQE spectra prove that the J_(sc)is mainly contributed by thephotocurrent generated in DBP and C_(60)layers.When the FIrpic thickness is 8 nm,the filmsurface is very uniform with the smallest water contact angle.The impedance spectro-scopy demonstrates that the device resistance gradually increases from 4.1×10^(4)Ω(without Flrpic)to 4.6×10^(4)Ω(with 10-nm Flrpic)with the FIrpic thickness rise,simultaneously the device transits from the insulating state into the conductive statefaster for the thin Flrpic layer than the thick layer.展开更多
Perovskite materials can realize the transition from green light to full-visible light spectrum by halogen anion exchange.Here,we designed an in-situ solid-phase anion-exchange method combined with inkjet printing to ...Perovskite materials can realize the transition from green light to full-visible light spectrum by halogen anion exchange.Here,we designed an in-situ solid-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-situ solid-phase anion-exchange with underlying Pe QDs,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.展开更多
Quasi-two-dimensional(quasi-2D)perovskites are promising materials for potential application in light-emitting diodes(LEDs)due to their high exciton binding energy and efficient emission.However,their luminescent perf...Quasi-two-dimensional(quasi-2D)perovskites are promising materials for potential application in light-emitting diodes(LEDs)due to their high exciton binding energy and efficient emission.However,their luminescent performance is limited by the low-n phases that act as quenching luminescence centers.Here,a novel strategy for eliminating low-n phases is proposed based on the doping of strontium bromide(SrBr_(2))in perovskites,in which SrBr_(2)is able to manipulate the growth of quasi-2D perovskites during their formation.It was reasonably inferred that SrBr_(2)readily dissociated strontium ions(Sr^(2+))in dimethyl sulfoxide solvent,and Sr^(2+)was preferentially adsorbed around[PbBr_(6)]^(4−)through strong electrostatic interaction between them,leading to a controllable growth of quasi-2D perovskites by appropriately increasing the formation energy of perovskites.It has been experimentally proved that the growth can almost completely eliminate low-n phases of quasi-2D perovskite films,which exhibited remarkably enhanced photoluminescence.A high electroluminescent efficiency matrix green quasi-2D perovskite-LED(PeLED)with a pixel density of 120 pixels per inch fabricated by inkjet printing technique was achieved,exhibiting a peak external quantum efficiency of 13.9%,which is the most efficient matrix green quasi-2D PeLED so far to our knowledge.展开更多
基金the National Natural Science Foundation of China (Grant Nos.61204087, 61306099)the Guangdong Natural Science Foundation (Grant No. S2012040007003)+2 种基金China Postdoctoral Science Foundation (2013M531841)the Fundamental Research Funds for the Central Universities (2014ZM0003, 2014ZM0034, 2014ZM0037, 2014ZZ0028)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20120172120008)
文摘A very-high color rendering index white organic light-emitting diode(WOLED) based on a simple structure was successfully fabricated. The optimized device exhibits a maximum total efficiency of 13.1 and 5.4 lm/W at 1,000 cd/m2. A peak color rendering index of 90 and a relatively stable color during a wide range of luminance were obtained. In addition, it was demonstrated that the 4,40,400-tri(9-carbazoyl) triphenylamine host influenced strongly the performance of this WOLED.These results may be beneficial to the design of both material and device architecture for high-performance WOLED.
基金supported in part by National Key R&D Program of China under Grant 2022YFB3603805,2024YFF1504501 and 2021YFB3600800in part by the National Natural Science Foundation of China under Grant 62474070 and 62074059+2 种基金in part by the Project of High-Mobility High-Stability Oxide TFT Development and Applications under Grant 2024ZD0604100in part by TCL science and technology innovation fundin part by the autonomous project of State Key Laboratory of Luminescent Materials and Devices under Grant Skllmd-2024-04。
文摘Stretchable optoelectronic synapses are attractive for intelligent perception,neuromorphic computation and visual adaptation.Here,we demonstrate a highly stretchable organic optoelectronic synaptic transistor(s-OOST)with a transconductance up to 86 mS that can simultaneously accept modulation of electrical pulses and multi-wavelength light signals(from ultraviolet to near-infrared).The s-OOST achieved highly reliable synaptic plasticity for brain-inspired computation and retinainspired perception even under 50%tensile strain.Furthermore,the devices exibited vision-adaptive near-infrared sensing ability that was verified by single-pixel scanning imaging.Finally,the multiwavelength(365 nm-1050 nm)optical synaptic properties were investigated under the applications of imaging memory,polychromatic optical communication and information security(coded by wavelength).This research advances the capabilities of the stretchable integrated systems with vision-adaptive sensing characteristic and computing-in-memory ability.
基金supported by CUI CAN Program of Guangdong Province(CC/XM-202401ZJ0201)National Natural Science Foundation of China(Grant 62174057)+4 种基金Guangdong Natural Science Foundation(2024A1515012216 and 2023A1515011026)Educational Commission of Guangdong Province(Grant 2022ZDZX1002)State Key Lab of Luminescent Materials and Devices(Skllmd-2024-05)Southwest Institute of Technology and Engineering Cooperation Fund(HDHDW59A020301)Guangdong Basic Research Center of Excellence for Energy and Information Polymer Materials.
文摘In_(2)O_(3)-based TFTs have garnered widespread attention due to their higher mobilities than amorphous silicon.Previous studies have indicated that rare earth doping can enhance the NBIS stability of TFTs,but this often results in a decrease in mobility.To improve the mobility of TFTs while maintaining stability,we incorporated Mo and Pr into In_(2)O_(3),fabricating InPrMoO TFTs.Mo doping is believed to positively affect In_(2)O_(3)through reducing porosity and defects.Pr doping has been proposed as a potential strategy to enhance the NBIS stability of In_(2)O_(3).A nondestructiveμPCD detector was employed to characterize the local defect states of the film.X-ray photoelectron spectroscopy data demonstrate that the InPrMoO film with 0.8 mol%Mo doping has the lowest concentration of oxygen vacancies(Vo).TFTs fabricated using the InPrMoO film doped with an optimized concentration of 0.8 mol%Mo exhibit superior electrical properties(μ_(sat)=12.2 cm^(2)/V·s,V_(th)=1.6 V,I_(on)/I_(off)=2.17×10^(6),and SS=0.47 V/dec)and the minimalΔVth under NBS/PBS/NBIS=−0.65 V/0.79 V/−0.70 V.The synergistic effect of Mo and Pr doping has led to enhanced film uniformity and density,consequently improving the mobility and stability of the TFTs.To tackle the challenge of predicting optimal process parameters,a multiobjective prediction model integrating physical models and machine learning was developed.The predicted optimal parameters(0.78 mol%Mo doping,381℃ annealing)were experimentally verified,yielding<5%relative error in most film properties.The prepared TFT exhibits a mobility of 13.5 cm^(2)/V·s(10.6%improvement),an on/off current ratio of 3.82�106,and an SS of 0.40 V/dec,demonstrating superior efficiency over conventional trial-and-error methods.
文摘Inkjet priming （IJP） is a versatile technique for realizing high-accuracy patterns in a cost-effective manner. It is considered to be one of the most promising candidates to replace the expensive thermal evaporation technique, which is hindered by the difficulty of fabricating low-cost, large electroluminescent devices, such as organic light- emitting diodes （OLEDs） and quantum dot light-emitting diodes （QLEDs）. In this invited review, we first introduce the recent progress of some printable emissive materials, including polymers, small molecules, and inorganic colloidal quantum dot emitters in OLEDs and QLEDs. Subsequently, we focus on the key factors that influence film formation. By exploring stable ink formulation, selecting print parameters, and implementing droplet deposition control, a uniform film can be obtained, which in turn improves the device performance. Finally, a series of impressive inkjet-printed OLEDs and QLEDs prototype display panels are summarized, suggesting a promising future for IJP in the fabrication of large and high-resolution flat panel displays.
基金supported by the National Key Research and Development Program of China (2016YFB0400701)Natural Science Foundation of Guangdong Joint Program (U1801258, U1301243)Department of Science and Technology of Guangdong Province (2019B010924003)。
文摘Organic electron-transport materials are an essential component to boost performances and stability of organic light-emitting diodes. We present a robust organic electron-transport compound 3-(6-(3-(4,6-bis(4-biphenylyl)-1,3,5-triazin-2-yl)phenyl)pyridin-2-yl)phenyldiphenylphosphine oxide by facilely coupling the triphenylphosphine oxide moiety to the 2-phenyl-4,6-bis(4-biphenylyl)-1,3,5-triazine unit via a 2,6-pyridinylene linker. It is well soluble in weakly polar solvents and possesses a high Tg of 123 ℃ with an exceptional Td≈470 ℃ at 1% weight loss and deep HOMO/LUMO levels of ca.-6.45/-3.06 eV. The phosphorescent spectrum measured in solid state at 77 K reveals a notable triplet energy of 2.88 eV. n-Doping with 8-hydroxyquinolatolithium(Liq) produces the electron mobility value of 4.66×10-5–3.21×10-4 cm2 V-1 s-1@(2–5)×105 V cm-1.Moreover, the contrasting solubility of the bromo reaction intermediate and the new compound in alcoholic solvents facilitates separation. The characterizations of bottom-and top-emission green phosphorescent OLEDs involving this single Liq-doped electron-transport layer reveal long stability. In particular, the latter provides outstanding performances with 77.4 cd A–1(corresponding to an EQE of 18.7%) and 86.8 lm W–1@ca. 1000 cd m-2, based on the green emitter bis(2-phenylpyridine)(2-(4-methyl-3-phenylphenyl)pyridine)iridium(Ⅲ). Moreover, driven by a constant current for ca. 640 h, the initial luminance of 1000 cd m–2 appears almost no decay.
基金supported by the National BasicResearch Program of China(2009CB623604)the National NaturalScience Foundation of China(61204087,51173049,U0634003,61036007,and 60937001)+1 种基金Fundamental Research Funds for the Central Universities(2011ZB0002,2011ZM0009)China Postdoctoral Science Foundation(2013M531841)
文摘Two kinds of highly efficient,bright hybrid white organic light emitting diodes have been fabricated by utilizing ambipolar material 4,4-N,N-dicarbazolebiphenyl(CBP)and unipolar material N,N0-di(naphthalene-1-yl)-N,N0-diphenyl-benzidine(NPB)as the spacer,respectively.By adjusting the thickness of spacers together with effectively utilizing combinations of exciton-harnessed orangephosphorescence/blue-fluorescence,the current efficiency of optimal device with CBP spacer and device with NPB spacer are 31.0 and 38.9 cd/A,the maximum power efficiency are 23.9 and 29.1 lm/W,the maximum brightness are 87,249 and 75,501 cd/m2,and the Commission Internationale de l’Eclairage(CIE)coordinates are(0.42,0.43)and(0.47,0.44)at a voltage of 11 V,respectively.Furthermore,systematic investigations focused on the effects of spacers on device performance have been performed.By virtue of the multifunctional spacer,energy transfer between the phosphorescent and fluorescent emitters can be avoided while the carriers still can pass through this spacer bridge,which is important to realize such high device performance.In addition,a novel concept that both ambipolar materials and unipolar materials can be the promising candidates for spacers has been proposed if the thickness of spacers with high triplet energy is optimized.
基金supported by the National Key Basic Research and Development Program of China (2015CB655004)the National Natural Science Foundation of China (U1601651, 51521002, U1301243, 61574061)the Educational Commission of Guangdong Province (2015B090914003, 2014KZDXM012)
文摘Making full-color active matrix display based on quantum dot light emitting diodes(AM-QLEDs) via ink-jet printing is attractive in display industry due to QLEDs' wide color gamut and their potential manufacturing advantages of large screen size and low cost. The challenges for realizing AM-QLED display are how to achieve high quality films through ink-jet printing, multi-color patterning, electroluminescence(EL) color purity, and high efficiency. Herein, a 2-inch diagonal full-color AM-QLEDs display with pixel density of 120 pixels per inch(PPI) fabricated by ink-jet printing technique is presented. Driven by a metal oxide TFT(MOTFT) back-panel, the display exhibits a maximum brightness of 400 cd m.2, and a color gamut of 109%(NTSC 1931). The red, green, and blue(RGB) monochrome QLEDs passive matrix panels fabricated by ink-jet printing technique have a current efficiency(CE) of 2.5, 13.9, and 0.30 cd A.1, respectively. To the best of our knowledge, the efficiencies are the highest among passive matrix QLEDs panels made by ink-jet printing technique. The ink-jet printed QDs films show good thickness uniformity due to high viscosity and low volatility of the printable inks, and no cross-contamination between adjacent pixels resulting from the hydrophobic pixel defining layer.
基金the National Key Research and Development Program of China(No.2017YFB0404404)the Open Fund of State Key Laboratory of Luminescent Materials and Devices(South China University of Technology),China。
文摘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 ineffi-cient 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(Nvinylcarbazole)(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 8.6103 to 4.2103 W at 1000 Hz.Finally,the electroluminescent stability of the co-host device was significantly enhanced by adjusting the annealing temperature.
基金supported by the National Key R&D Program of China(2016YFB0400701)NSFC-Guangdong Joint Program(U1301243)+1 种基金the National Basic Research Program of China(2015CB655000)support of Dongguan Major Special Project(2017215117010)
文摘There has been an increasing demand for high-performance and cost-effective organic electron-transport materials for organic light-emitting diodes （OLEDs）. In this contribution, we present a simple compound 3-（3-（4,6-diphenyl-l,3,5-triazin-2-yl）phenyl）-1,10-phenanthroline through the facile Pd-catalyzed coupling of a triphenyltriazine boronic ester with 3-hromo-1,10-phenanthroline. It shows a high Tg of 112℃. The ultraviolet photoelectron spectroscopy measurements reveal a deep HOMO level of -6.5 eV. The LUMO level is derived as -3.0 eV, based on the optical bandgap. The low-temperature solid-state phosphorescent spectrum gives a triplet energy of -2.36eV. n-Doping with 8-hydroxyquinolatolithium （Liq, 1：1） leads to considerably improved electron mobility of 5.2 × 10 -6 -5.8 × 10 -5 cm2 v-1 S-1 at E=（2-5） × 10 5Vcm -1, in contrast with the triarylphosphine oxide- phenantroline molecular conjugate we reported previously. It has been shown that through optimizing the device structure and hence suppressing polaron-exciton annihilation, introducing this single Liq-doped electron-transport layer could offer high-efficiency and stable phosphorescent OLEDs.
基金supported by the Pearl River S&T Nova Program of Guangzhou (201710010194)the National Natural Science Foundation of China (61574061, 21520102006, 21634004, 51521002, 91633301)the Foundation of Guangzhou Science and Technology Project (201707020019)
文摘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 HNO3 derivatives.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 structureproperty 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.
基金supported by the National Basic Research Program of China(2015CB655004)the National Natural Science Foundation of China(61401156,U1601651,and U1301243)+3 种基金Pearl Rive S&T Nova Program of Guangzhou(201710010066,201610010052)the Fundamental Research Funds for the Central Universities(2017MS008)China Postdoctoral Science Foundation(2017T100627)Tiptop Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2015TQ01C777,2016TQ03C331)
文摘Tandem white organic light-emitting diodes(WOLEDs) are of great research interest since they can greatly boost the performance compared with the single-unit counterparts. However, their structures are more complicated than those of single-unit OLEDs. Besides, to achieve high performance, the doping technology is required to tandem OLEDs, particularly for tandem WOLEDs, further complicating the structures. Herein, doping-free tandem WOLEDs, for the first time, have been demonstrated. By managing an effective doping-free charge generation layer to interconnect doping-free emitting layers/charge transport layers, high-performance doping-free tandem WOLEDs have been developed. The blueyellow device accomplishes the simplified structure/short fabrication time/reduced cost/high efficiency/low efficiency roll-off/low voltage/high luminance trade-off, which cannot be achieved by previous tandem WOLEDs. Remarkably, the efficiency(81.2 cd A^(-1)) is ~2-fold higher than the highest efficiency of previous doping-free WOLEDs and even higher than those of some best doping tandem WOLEDs. The maximum luminance is 44,886 cd m^(-2), which is the highest for doping-free WOLEDs.Besides, the blue-red device can exhibit a color rendering index(CRI) of 67, which is even higher than that of some representative three-color tandem WOLEDs. Such findings may not only represent a significant step for doping-free WOLEDs, but unlock a novel avenue that doping-free tandem WOLEDs are promising to achieve the simplicity and high performance trade-off.
基金supported by the National Natural Science Foundation of China(Grant Nos.51771074,62074059,and 22090024)Guangdong Major Project of Basic and Applied Basic Research(No.2019B030302007)+5 种基金Fundamental Research Funds for the Central Universities(Nos.2020ZYGXZR060 and 2019MS012)Guangdong Natural Science Foundation(No.2018A0303130211)South China University of Technology 100 Step Ladder Climbing Plan Research Project(Nos.j2tw202004035,j2tw202004034,and j2tw202004095)National College Students Innovation and Entrepreneurship Training Program(Nos.202010561001,202010561004,and 202010561009)2021 Guangdong University Student Science and Technology Innovation Special Fund(“Climbing Plan”Special Fund)(No.pdjh2021b0036)Ji Hua Laboratory Scientific Research Project(X190221TF191).
文摘Flexible thin-film transistors with high current-driven capability are of great significance for the next-generation new display technology.The effect of a Cu-Cr-Zr(CCZ)copper alloy source/drain(S/D)electrode on flexible amorphous neodymiumdoped indium-zinc-oxide thin-film transistors(NdIZO-TFTs)was investigated.Compared with pure copper(Cu)and aluminum(Al)S/D electrodes,the CCZ S/D electrode changes the TFT working mode from depletion mode to enhancement mode,which is ascribed to the alloy-assisted interface layer besides work function matching.X-ray photoelectron spectroscopy(XPS)depth profile analysis was conducted to examine the chemical states of the contact interface,and the result suggested that chromium(Cr)oxide and zirconium(Zr)oxide aggregate at the interface between the S/D electrode and the active layer,acting as a potential barrier against residual free electron carriers.The optimal NdIZO-TFT exhibited a desired performance with a saturation mobility(μsat)of 40.3 cm^(2)·V-1·s^(-1),an Ion/Ioff ratio of 1:24×10^(8),a subthreshold swing(SS)value of 0.12 V·decade^(-1),and a threshold voltage(Vth)of 0.83 V.This work is anticipated to provide a novel approach to the realization of highperformance flexible NdIZO-TFTs working in enhancement mode.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.22090024,51521002 and 62074059)the Basic and Applied Basic Research Major Program of Guangdong Province(Grant No.2019B030302007).
文摘Perovskite quantum dots(PeQDs)are considered potential display materials due to their high color purity,high photoluminescence quantum yield(PLQY),low cost and easy film casting.In this work,a novel electroluminescence(EL)device consisting of the interface layer of long alkyl-based oleylammonium bromide(OAmBr),which passivates the surface defects of PeQDs and adjusts the carrier transport properties,was designed.The PLQY of the OAmBr/PeQD bilayer was significantly improved.A high-performance EL device with the structure of indium tin oxide/poly(3,4-ethylenedioxythiophene)polystyrene sulfonate/poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine)/OAmBr/PeQDs/2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1H benzimidazole)/LiF/Al was constructed using a spin-coating method.A peak external quantum efficiency(EQE)of 16.5%at the emission wavelength of 646 nm was obtained.Furthermore,an efficient matrix EL device was fabricated using an inkjet printing method.A high-quality PeQD matrix film was obtained by introducing small amounts of polybutene into the PeQDs to improve the printing process.The EQE reached 9.6%for the matrix device with 120 pixels per inch and the same device structure as that of the spin-coating one.
文摘Introducing ethynylene linkages in a conjugated molecule can deepen the HOMO level, decrease the steric con- straints and better delocalize the n electrons and so on, which are beneficial for organic solar cells. Furthermore, the typical method of introducing acetylene linkages by Sonogashira reactions can avoid the usage of toxic stannyl in- termediates and potentially dangerous lithiation reactions. In this study, two simple small molecules BEDPP and NEDPP are designed and synthesized, in which two diketopyrrolopyrrole units are symmetrically connected to benzene and naphthalene cores, respectively, via acetylene linkages. And the BHJ （Bulk Heterojunction） solar cells based on BEDPP and NEDPP without using solvent additive and without any post-treatment for the active layers provide us power conversion efficieneies of 1.48% and 2.31% with remarkably high open circuit voltages up to 0.90 and 0.98 V, respectively.
基金supported by the NationalNatural Science Foundation of China(Grant Nos.6167410l and 61504077)the Open Fund of State Key Laboratory of Luminescent Materials and Devices(South China University of Technology),China.
文摘In this work,a sky-blue luminescent down-shifting(LDS)layer bis[(4,6-difluorophenyl)-pyridinato-N,C^(2')]c(picolinate)iridium(II)(FIrpic)was inserted between tetraphenyl dibenzoperiflanthene(DBP)and Mo0_(3)as UV-screen and sensitizer for smallmolecule DBP/C_(60)based planar heterojunction(PHJ)solar cells.With 8-nm Flrpic theshort circuit current(J_(sc))and power conversion efficiency(PCE)of the device areenhanced by 28%and 15%,respectively,probably originating from the re-absorption ofthe photons emitted from Flrpic.The V_(oc)linearly increases over 1-nm Flrpic,ascribed tothe deeper HOMO level of Flrpic than DBP,while the fill factor continuously declines from 3-to 10-nm Flrpic.The EQE spectra prove that the J_(sc)is mainly contributed by thephotocurrent generated in DBP and C_(60)layers.When the FIrpic thickness is 8 nm,the filmsurface is very uniform with the smallest water contact angle.The impedance spectro-scopy demonstrates that the device resistance gradually increases from 4.1×10^(4)Ω(without Flrpic)to 4.6×10^(4)Ω(with 10-nm Flrpic)with the FIrpic thickness rise,simultaneously the device transits from the insulating state into the conductive statefaster for the thin Flrpic layer than the thick layer.
基金supported by Key R&D Plan of Guangdong Province(2022B0303010001)the National Natural Science Foundation of China(52073104)。
文摘Perovskite materials can realize the transition from green light to full-visible light spectrum by halogen anion exchange.Here,we designed an in-situ solid-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-situ solid-phase anion-exchange with underlying Pe QDs,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.
基金This work was supported by the NSFC(Grant Nos.22090024 and 62074059)the Science and Technology Project of Guangdong Province(Grant No.2019B030302007).
文摘Quasi-two-dimensional(quasi-2D)perovskites are promising materials for potential application in light-emitting diodes(LEDs)due to their high exciton binding energy and efficient emission.However,their luminescent performance is limited by the low-n phases that act as quenching luminescence centers.Here,a novel strategy for eliminating low-n phases is proposed based on the doping of strontium bromide(SrBr_(2))in perovskites,in which SrBr_(2)is able to manipulate the growth of quasi-2D perovskites during their formation.It was reasonably inferred that SrBr_(2)readily dissociated strontium ions(Sr^(2+))in dimethyl sulfoxide solvent,and Sr^(2+)was preferentially adsorbed around[PbBr_(6)]^(4−)through strong electrostatic interaction between them,leading to a controllable growth of quasi-2D perovskites by appropriately increasing the formation energy of perovskites.It has been experimentally proved that the growth can almost completely eliminate low-n phases of quasi-2D perovskite films,which exhibited remarkably enhanced photoluminescence.A high electroluminescent efficiency matrix green quasi-2D perovskite-LED(PeLED)with a pixel density of 120 pixels per inch fabricated by inkjet printing technique was achieved,exhibiting a peak external quantum efficiency of 13.9%,which is the most efficient matrix green quasi-2D PeLED so far to our knowledge.
