Ink formulation, scalable applications and challenging perspectives of screen printing for emerging printed microelectronics

Screen printing is regarded as a highly competitive manufacture technology for scalable and fast fabrication of printed microelectronics, owing to its advanced merits of low-cost, facile operability and scalability.However, its large-scale application in printed microelectronics is still limited by screen printing functional ink. In this review, we summarize the recent advances of ink formation, typical scalable applications, and challenging perspectives of screen printing for emerging printed microelectronics. Firstly, we introduce the major mechanism of screen printing and the formation of different organic-and aqueous-based inks by various solvents and binders. Next, we review the most widely used applications of screen printing technique in micro-batteries, micro-supercapacitors and micro-sensors, demonstrative of wide applicability.Finally, the perspectives and future challenges in the sight of screen printing are briefly discussed.

Highly Conductive Fractal-structured Silver Particles for Preparing Flexible Printed Circuits via Screen Printing

Fractal-structured silver particles(FSSPs)are conductive materials with a micron-scale trunk and nanoscale branches,and are characterized with high electrical conductivity and high connectivity.In this study,FSSPs were added to an aqueous additive solution for synthesizing a conductive ink,which was used to prepare two types of printing electrodes via screen printing.The first type included two flexible printed electrodes(FPEs):an FPE on a polyethylene terephthalate(PET)film and an FPE on paper.The second one was a polydimethylsiloxane(PDMS)-embedded FPE.The PETbased FPE exhibited high electrochemical stability when its sheet resistance was 0.38Ω/sq for a 50%(w/w)content of FSSPs in the prepared conductive ink.Moreover,the embedded FPE demonstrated excellent mechanical properties and high chemical stability.In addition,the embedded structure was endowed with stretchability,which is important for different devices,such as flexible biomedical sensors and flexible electronics.

Size effect enabling additive-free MXene ink with ultrahigh conductivity for screen printing of wireless electronics

Facile preparation of additive-free inks with both high viscosity and high conductivity is critical for scalable screen printing of wireless electronics,yet very challenging.MXene materials exhibit excellent conductivity and hydrophilicity,showing great potential in the field of additive-free inks for screen printing.Here,we demonstrate the synthesis of additive-free two-dimensional(2D)titanium carbide MXene inks,and realize screen-printed MXene wireless electronics for the first time.The viscosity of MXene ink is solely regulated by tuning the size of MXene nanosheet without any additives,hence rendering the printed MXene film extremely high conductivity of 1.67×10^(5) S/m and fine printing resolution down to 0.05 mm on various flexible substrates.Moreover,radio frequency identification(RFID)tags fabricated using the additive-free MXene ink via screen printing exhibit stable antenna reading performance and superb flexibility.This article,thus offers a new route for the efficient,low-cost and pollution-free manufacture of printable electronics based on additive-free MXene inks.

Effect of processing parameters on in situ screen printing-assisted synthesis and electrical properties of Ti3SiC2-based structures

This work reports on the development of pastes containing Ti,TiC,Si,and C elementary powders for in situ synthesis of Ti3SiC2 via screen printing.Four paste compositions were manufactured using two powder mixtures(Ti/Si/C and Ti/TiC/Si/C)with different stoichiometry.The pastes were screen printed onto Al2O3 substrates and sintered at 1400℃in argon varying the dwell time from 1 to 5 h.The printed pastes containing TiC and excess of Si exhibited the lowest surface roughness and after 5 h sintering comprised of Ti3SiC2 as the majority phase.The electrical conductivity of this sample was found to range from 4.63×10^(4)to 2.57×10^(5)S·m^(-1)in a temperature range of 25-400℃.

Flexible carbon nanotube-enriched silver electrode films with high electrical conductivity and reliability prepared by facile screen printing

Flexible electrode films play critical and fundamental roles in the successful development of flexible electronic devices. In this study, carbon nanotubes（CNTs） were implanted into silver（Ag） ink to enhance the electrical conductivity and the reliability of the printed Ag electrode films. The fabricated carbon nanotubes-enriched silver（Ag-CNTs） electrode films were printed on the polyimide substrates by a facile screen printing method and sintered at a relatively low temperature. The resistivity of Ag-CNTs films was decreased by 62.27% compared with the pure Ag film. Additionally, the Ag-CNTs films exhibited excellent flexibility under a bending radius of 4 mm（strain ε = 2.09%） over 1000 cycles. Furthermore, the Ag-CNTs film displayed unchangeable electrical conductivity together with a strong adhesion after an accelerated aging test with 500 thermal shock cycles. These improvements were attributed to the AgCNTs interconnected network structure, which can provide electronic transmission channels and prevent cracks from initiating and propagating.

Screen printing of upconversion NaYF4:Yb3+/Eu3+ with Li+ doped for anti-counterfeiting application

Li ions affect the upconversion efficiency by changing the local crystal field of the luminescent center. Herein, in order to improve the upconversion efficiency of NaYF4:Yb3+/Eu3+, a series of NaYF4:Yb3+/Eu3+micro-particles with different Li+doping concentrations were synthesized by the hydrothermal synthesis method, respectively.Firstly, the structure and morphology of NaYF4:Yb3+/Eu3+upconversion micro-particles(UCMPs) with different doping concentrations were analyzed by X-ray diffraction and a scanning electron microscope(SEM). SEM results show that the UCMPs are not only highly crystallized, but also have hexagons with different Li+concentrations of NaYF4:Yb3+/Eu3+. X-ray diffraction shows that the crystal field around Eu3+changes with the increase of Li+concentration. Then, the fluorescence spectrum of NaYF4:Yb3+/Eu3+was studied under the irradiation of a 980 nm laser. The results show that the fluorescence intensity of NaYF4:Yb3+/Eu3+with2% Li+is the strongest, which is twice the intensity of NaYF4:Yb3+/Eu3+without Li+. Finally, the fluorescence imaging analysis of NaYF4:Yb3+/Eu3+with 2% Li+concentration was carried out. The UCMPs are used to screen printing to evaluate the imaging effect on different sample surfaces. The results show NaYF4:Yb3+/Eu3+(with 2% Li+) has great application prospects in anti-counterfeiting recognition.

Screen printing process control for coating high throughput titanium dioxide films toward printable mesoscopic perovskite solar cells

Screen printing technique has been widely applied for the manufacturing of both traditional silicon solar cells and emerging photovoltaics such as dyesensitized solar cells(DSSCs)and perovskite solar cells(PSCs).Particularly,we have developed a printable mesoscopic PSC based on a triple layer scaffold of TiO2/ZrO2/carbon.The deposition of the scaftold is entirely based on screen printing process,which provides a promising prospect for low-cost photovoltaics.However,the optimal thickness of the TiO2 layer for fabricating efficient printable PSCs is much smaller than the typical thickness of screen printed films.Here,we tune the concentration of the pastes and the printing parameters for coating TiO?films,and successfully print TiO2 films with the thickness of 500-550 nm.The correlation between the thickness of the films and printing parameters such as the solid content and viscosity of the pastes,the printing speed and pressure,and the temperature has been investigated.Besides,the edge effect that the edge of the TiO2 films possesses a much larger thickness and printing positional accuracy have been studied.This work will significantly benefit the further development of printable mesoscopic PSCs.

A disposable cobalt-based phosphate sensor based on screen printing technology

Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consists of a fully integrated cobalt （Co） electrode, which is a layer of carbon conductive ink （C） physically doped with Co powder, and Ag/AgCI reference electrode. The SEM images show that the morphology of the Co electrode changes after exposure to the phosphate solution, indicating that the expendable reaction exists during the measurement. At the Co/C ratio of 1：99, the cobalt-based phosphate sensor shows phosphate-selective potential response in the range of 10-4 to 10-1 mol/L, yielding a detection limit of lxl0-5 mol/L and a slope of over 30 mV/decade in acidic solution （pH 4.5） for HzPO4-. The proposed screen-printed sensor also ex- hibited significant reproducibility with a small repeated sensing deviation （i.e., relative standard deviation （R.S.D.） of 0.5%） on a single sensor and a small electrode-to-electrode deviation （i.e., R.S.D. 〈 3.2%）. The recovery study of HzPO4- in real wastewater samples gave values from 95.4% to 101.8%, confirming its application potential in the measurement of phosphate in real samples. Apart from its high selectivity, sensitivity, and stability comparable with a conventional bulk Co-wire electrode, the proposed phosphate sensor still yields many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices such as flow injection analysis.

SYNTHESIS OF CoFe_(2)O_(4)/Pb(Zr_(0.53)Ti_(0.47))O_(3)MULTIFERROIC COMPOSITE THICK FILMS BY LOW-SINTERING-TEMPERATURE SCREEN PRINTING METHOD

CoFe_(2)O_(4)/Pb(Zr_(0.53)Ti_(0.47))TO_(3)(abbreviated as CFO/PZT)multiferroic composite thick films were successfully fabricated on alumina substrate with gold bottom electrode by screen printing method at a low-sintering temperature.The processing included the modi fication and dispersion of ferromagnetic CFO powder and ferroelectric PZT powder,the preparation of uniform pastes,and the selection of proper annealing temperature for composite thick films.Transmission electron microscopic pictures(TEM)indicated the submicron meter of particles size for both CFO and PZT particles.After annealing at 900℃ for 1 h in air,tape test con firmed the quality of multiferroic thick films as well as pure CFO and PZT films.X-ray diffraction(XRD)showed a coexistence of CFO and PZT phases;furthermore,a smooth surface was observed through scanning electron microscopic(SEM)pictures along with the sharp cross-sectional picture,indicative of 100
m of film thickness.Ferromagnetic and ferroelectric properties were observed in CFO/PZT films simultaneously at room temperature.Compared with the reported CFO/PZT multiferrroic thin films,the present ferromagnetic property was closing to that of the chemical solgel synthesized film and even that from the physical pulsed laser deposition technique.However,the ferroelectric property showed a degenerated behavior,possible reasons for this was discussed and further optimization was also proposed for the potential multifunctional application.

It's Closed In Triumph,'97 International Screen Special Printing Technology Exhibition

’97 Wuhan International Screen Special Printing Technology Exhibition was held from May 21—24, 1997 in Wuhan city,the capital of Hubei Province. 120 famous exhibitors from China, USA, Canada, Holland, Japan, Korea, and Hong Kong, Taiwan districts attended the Exhibition. The booth area was more than 5000 m^2.

A personalized electronic textile for ultrasensitive pressure sensing enabled by biocompatible MXene/ PEDOT:PSS composite

Flexible,breathable,and highly sensitive pressure sensors have increasingly become a focal point of interest due to their pivotal role in healthcare monitoring,advanced electronic skin applications,and disease diagnosis.However,traditional methods,involving elastomer film-based substrates or encapsulation techniques,often fall short due to mechanical mismatches,discomfort,lack of breathability,and limitations in sensing abilities.Consequently,there is a pressing need,yet it remains a significant challenge to create pressure sensors that are not only highly breathable,flexible,and comfortable but also sensitive,durable,and biocompatible.Herein,we present a biocompatible and breathable fabric-based pressure sensor,using nonwoven fabrics as both the sensing electrode(coated with MXene/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate[PEDOT:PSS])and the interdigitated electrode(printed with MXene pattern)via a scalable spray-coating and screen-coating technique.The resultant device exhibits commendable air permeability,biocompatibility,and pressure sensing performance,including a remarkable sensitivity(754.5 kPa^(−1)),rapid response/recovery time(180/110 ms),and robust cycling stability.Furthermore,the integration of PEDOT:PSS plays a crucial role in protecting the MXene nanosheets from oxidation,significantly enhancing the device's long-term durability.These outstanding features make this sensor highly suitable for applications in fullrange human activities detection and disease diagnosis.Our study underscores the promising future of flexible pressure sensors in the realm of intelligent wearable electronics,setting a new benchmark for the industry.

Highly Concentrated,Conductive,Defect-free Graphene Ink for Screen-Printed Sensor Application

Conductive inks based on graphene materials have received significant attention for the fabrication of a wide range of printed and flexible devices.However,the application of graphene fillers is limited by their restricted mass production and the low concentration of their suspensions.In this study,a highly concentrated and conductive ink based on defect-free graphene was developed by a scalable fluid dynamics process.A high shear exfoliation and mixing process enabled the production of graphene at a high concentration of 47.5 mg mL^(−1)for graphene ink.The screen-printed graphene conductor exhibits a high electrical conductivity of 1.49×10^(4)S m^(−1)and maintains high conductivity under mechanical bending,compressing,and fatigue tests.Based on the as-prepared graphene ink,a printed electrochemical sodium ion(Na^(+))sensor that shows high potentiometric sensing performance was fabricated.Further,by integrating a wireless electronic module,a prototype Na^(+)-sensing watch is demonstrated for the real-time monitoring of the sodium ion concentration in human sweat during the indoor exercise of a volunteer.The scalable and efficient procedure for the preparation of graphene ink presented in this work is very promising for the low-cost,reproducible,and large-scale printing of flexible and wearable electronic devices.

Correlation between Ozone and Total VOCs in Printing Environment

In this study, indoor air quality （IAQ） assessments were carried out in a screen printing facility. The air sampling was conducted in press department, including two different types of screen printing machines： semi-automatic and automatic. Air samples were collected and analyzed in situ for 4 times, once per 2 hours, during working time of 8 hours. Analysis of the experimental data showed that ambient ozone concentrations slowly increases with the increasing of TVOCs concentration and intensive use of UV lamps during automatic screen printing process. Therefore, the detected concentration levels of ozone and VOCs were compared with the Occupational Safety and Health Administration （OSHA） and Serbian Regulation. Comparison of the two mentioned standard regulations, the ozone concentrations in indoor printing air were from 0.83 to 8.1 and 2.4 to 16.2 times higher in the relation to the prescribed PEL and maximum allowed concentration （MAC） values, respectively, while the concentrations of particular VOCs were much below the PEL prescribed by the OSHA.

Bending and Washing Reliabilities of Screen-Printed UHF RFID Tags Based on Woven Water-Mark Fabric

Compared with bar code and quick response( QR) code in the storage and retailing management of textiles, the ultra-high frequency( UHF) radio frequency identification( RFID) tags have high information capacity as well as reliability in complex environmental conditions. In this study,the UHF RFID tags with perfect integration with textiles are assembled with screen-printed antenna on woven water-mark nylon fabric and Alien UHF integrated circuit( IC), and their reading performance under various washing and bending conditions is evaluated by an RFID reader. The results show that the tags after fifty bending( both arch and sink) cycles of screen-printed antenna still have reading distance more than 5.5 m,and an average reading distance is over 4.0 m after five washing cycles. The experimental results demonstrate that the tag antenna on the water-mark fabric can be manufactured by the screen-printing technology,and a coating process on this fabric facilitates the reading performance and the resistance against complex mechanical impact.

Print Screen键“酷传”

嗨!大家好,先做个自我介绍J:我叫Print Screen,怎么样?我的名字够酷吧。我住在“电脑王国”中“键盘城市”的“光标/编辑小区”里(其实严格点讲,我并不属于“光标/编辑小区”。嘘……大家可不要告诉我的兄弟姐妹们,不然他们非得开除我的“键籍”不可)。我的主要工作是:抓取显示在屏幕上的图案,然后可以和“画图叔叔”者“Photoshop阿姨”这些掌管图像处理大权的长辈们合作,把抓下来的图案[粘贴]出来,供大家使用。今天,我亲自展示4酷酷小技巧,请大家观看。

Enhanced Field Emission from Printed Carbon Nanotubes by Hard Hairbrush

A method, the morphology of screen printed carbon nanotube pastes is modified using a hard hairbrush, is presented. In this way, the organic matrix material is preferentially removed. Compared to those untreated films, the turn-on electric field of the treated film decreases from 2.2V/μm to 1.6V/μm, while the total emission current of the treated increases from 0.6mA/cm2 to 3mA/cm2, and uniform emission site density image has also been observed.

Development of Disposable Amperometric Cholesterol Biosensor

A novel disposable cholesterol biosensor based on electrochemical process is developed adopting screen printing technology.The system consists of a graphite reference electrode and a working electrode.The mixture of cholesterol oxidase and K_4Fe (CN)_6 is printed on the electrodes.The biosensor determines total cholesterol content through indirect determination of free cholesterol in the whole human blood.When 0.3V voltage is applied to the electrodes,the range of detection is from 250 mg/L to 2000 mg/L,with the correlation coefficient of 0.9967.The total detective duration is less than 200s,and the sample volume is only 4μL.

Low Cost Fabrication of Parallel Grid Electrode Group for Carbon Nanotube Field Emission Display

Based on simple screen printing technique,the parallel grid electrode group was developed. One grid electrode included the left and the right branch electrodes,which were formed with the solidified silver slurry on grid substrate. Under one anode pixel,the left and the right branch electrodes would control respectively the electron emission of two independent carbon nanotube (CNT) field emitters on the same cathode electrode. With the parallel grid electrode group, the capacitance effect between grid-cathode electrodes would be reduced due to the decreased grid electrode fabrication area. And the service life of field emission display (FED) could be prolonged owing to the existence of spare branch electrode. Using CNT as field emitter,the FED with parallel grid electrode group was fabricated,which possessed better grid control performance, high luminescence image brightness, and low fabrication cost. The turn-on electric-field was 2. 13 V /mm and the maximum field emission current had reached 1 506. 2 mA.

Large-scale manufacturing of functional single-atom ink for convenient glucose sensing

Printing techniques hold great potential in the manufacture of electronics such as sensors,micro-supercapacitors,and flexible electronics.However,developing large-scale functional conductive inks with appropriate rheological properties and active components still remains a challenge.Herein,through optimizing the formulations of ink,iron single sites supported N-doped carbon black(Fe_(1)-NC)inks can serve as both conductive electrodes and high-reactive catalysts to realize convenient glucose detection,which pronouncedly reduces the dosage of enzyme and simplifies the sensors preparation.In detail,utilizing in-situ pyrolysis method,Fe_(1)-NC single-atom catalysts(SACs)are prepared in bulk(dekagram-level).The batched Fe_(1)-NC SACs materials can be uniformly mixed with modulated ink to realize the screen printing with high resolution and uniformity.Also,the whole scalable preparation and ink-functional process can be extended to various metals(including Co,Ni,Cu,and Mn).The introduction of highly active Fe_(1)-NC sites reduces the amount of enzyme used in glucose detection by at least 50%,contributing to the cost reduction of sensors.The strategy in harnessing the SACs onto the carbon inks thus provides a broad prospect for the low-cost and large-scale printing of sensitive sensing devices.