当前位置：搜档网 › Stackable spectral-sensitive conductive films based on cyanine aggregates via an inkjet method

Stackable spectral-sensitive conductive films based on cyanine aggregates via an inkjet method

Stackable spectral-sensitive conductive ?lms based on cyanine aggregates via an inkjet method

Tokuma Nakamichi b ,Yu Yang a ,b ,*,Tomoya Ohta b ,Hiroaki Yoshioka b ,Masayuki Yahiro c ,Masanao Era d ,Hirofumi Watanabe b ,Yuanjing Cui a ,Yuji Oki b ,**,Guodong Qian a

State Key Laboratory of Silicon Materials,Cyrus Tang Center for Sensor Materials and Applications,Department of Materials Science &Engineering,Zhejiang University,Hangzhou 310027,PR China b

Department of Electronics,Graduate School of Information Science and Electrical Engineering,Kyushu University,Fukuoka 819-0395,Japan c

Institutes of Systems,Information Technologies and Nanotechnologies,Fukuoka 814-0001,Japan d

Department of Chemistry and Applied Chemistry,Faculty of Science and Engineering,Saga University,Saga 840-8502,Japan

a r t i c l e i n f o

Article history:

Received 19January 2013Received in revised form 19March 2013

Accepted 21March 2013

Available online 28March 2013Keywords:

Bulk-hetero photodiodes J-type aggregate Inkjet

Cyanine dye

Open-circuit voltage Fibril structure

a b s t r a c t

In this work,wavelength sensitive organic bulk-hetero photodiodes were fabricated by a piezoelectric inkjet method based on the J-type aggregates of cyanine dye molecules doped into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)thin ?lms on indium tin oxide anodes.The cyanine dye concentration in the inkjet printed ?lms was optimized and the J-aggregate formation during the drying process was investigated by local absorption spectra.It was found that at lower dye concentrations,not only the J-aggregate formation but also the radiation sensitivities of the ?lms were improved signi ?-cantly.Moreover,the stacking of the cyanine dye e poly(3,4-ethylenedioxythiophene):poly(styrene sul-fonate)spots demonstrated the linear increase on the optical density and ?lm thickness without deteriorating the J-aggregate formation,indicating their potential in application as narrow band ?lters.

1.Introduction

Over the last few years,inkjet printing has attracted extensive research interest as a direct patterning technique for the cost-effective fabrication of organic optoelectronic devices such as organic light-emitting diodes (OLEDs)[1e 4],organic ?eld-effect transistors (OFETs)[5e 7],organic solar cells (OSCs)[8e 10],and microstructures and tracks,etc [11e 15].In comparison with other ?lm deposition techniques for organic chemicals,the inkjet method was highly preferable owing to its versatility,miniaturization,and high-precision patterning.Inkjet printing especially the drop-on-demand (DoD)had the advantages such as being fast and simple with high throughput.The consumption of materials could be reduced to an extremely low level,pico liter of each droplet in

volume,providing a low cost,mask free,and non-contact printing approach [1].It was suggested that DoD inkjet printing might be one of the most suitable technical pathways for the fabrication of integratable and miniaturized optoelectronic elements,e.g.pho-todiodes and narrow band ?lters on disposable micro-?ow cytometry chips [16,17].The other techniques such as spin-coating or dip-coating were not applicable on these occasions because of the complicated structures of the ?ow cytometry chips,risk of contamination,and infeasibility to integrate various func-tional elements on one single chip.In this concern,organic pho-todiodes in the visible region were recently developed by the piezoelectric inkjet printing technique by our group for the ?rst time,which demonstrated the resolving capability on incident wavelength or energy [17e 20].

As the active materials for photodiodes which were capable of spectral resolving,J-type aggregates of cyanine dyes were adopted.Due to the hydrophobic character of their molecular frames,cyanine dyes tended to form self-aggregates in aqueous solutions,which have wide applications [21]and could be classi ?ed into J-or H-type aggregates,with an intense red-shifted or broad hyp-sochemically shifted absorption spectrum respectively,in

*Corresponding author.State Key Laboratory of Silicon Materials,Cyrus Tang Center for Sensor Materials and Applications,Department of Materials Science &Engineering,Zhejiang University,Hangzhou 310027,PR China.Tel.:t86057187952873.

**Corresponding author.Tel.:t810928023742.

E-mail addresses:yuyang@https://www.sodocs.net/doc/8c3405667.html, (Y.Yang),oki@ed.kyushu-u.ac.jp (Y.

Oki).Contents lists available at SciVerse ScienceDirect

Dyes and Pigments

journal homepage:w ww.else

https://www.sodocs.net/doc/8c3405667.html,/locate/dyepig

Dyes and Pigments 98(2013)333e 338

comparison with the monomer counterparts,depending on the angle between the transition dipoles and molecular axis of the aggregate[22,23].

In our previous reports,an inkjet fabrication method on the J-aggregated cyanine dye doped conductive polymer?lms has been introduced,followed by the development of a disposable and printable organic bulk-hetero junction photodiodes,which showed spectral resolving capabilities at the absorption peak of each cyanine dye,due to the narrow band absorption of the J-aggregates [19,20].However,some crucial problems remain pending.For instance,as key parameters of these organic photodiodes,the spectral resolution and sensitivity were low,which were suggested to be ascribed to the unoptimized J-aggregate formation during the printing process.Because of the restriction on solution viscosity for stable droplets ejection,which was mainly decided by the dye and polymer concentrations,the average?lm thickness was normally less than40nm,which limited the optical density of the?lm to be less than0.7at the absorption peak.Thus,the composition ratio of the cyanine dye to the conductive polymer was constrained to be high in our previous reports so as to keep the optical density at a practical level[19,20].The unoptimized cyanine dye concentration and as a result,the poor J-aggregate formation and limited optical density might be partially responsible for the low sensitivity and spectral resolution of the organic bulk-hetero photodiodes and also impeded their other applications,for instance,as the narrow band optical?lters.

In this work,the dependence of J-aggregate formation on the cyanine dye concentration in inkjet printed?lms was investigated by the macroscopic and local absorption spectra,respectively.It was found that the spectral-resolving capability and radiative sensitivity in name of quantum ef?ciency of organic bulk-hetero photodiodes at lower cyanine dye concentration were improved signi?cantly due to the better J-aggregate formation and depres-

sion on?bril structures.Moreover,the optical density of the?lms could be tailored linearly by stacking of layers vertically while the J-aggregate formation was retained,indicating that stackable inkjet fabrication as a promising method for disposable miniaturized optical elements,e.g.narrow band?lters in the visible region.

2.Experimental section

The cyanine dye,5-phenyl-2-(2-{[5-phenyl-3-(3-sulfopropyl)-2-(3H)-benzoxazolylidene]methyl}-l-butenyl)-3-(3-sulfopropyl) benzoxazolium hydroxide,inner salt,compound with triethyl-amine(NK-1952,Hayashibara Biochemical Lab.)and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS, Sigma e Aldrich,0.175wt%in H2O solution)were used as received without further puri?cation.The chemical structures of NK-1952 and PEDOT:PSS were shown in Fig.1.Firstly,the NK-1952/ PEDOT:PSS solution was made by mixing the cyanine dye with PEDOT:PSS in aqueous solution with the deionized water contain-ing a trace of surfactant(Triton-X).The dye/polymer ratio was kept at2.5:1,5:1,7.5:1,and10:1in weight,respectively.After vigorous stirring followed by the ultrasonic treatment to complete the dissolution of the dye,the viscous NK-1952/PEDOT:PSS solutions were?ltered(Whatman?lter GF/B1.0m m)before use.

A piezoelectric inkjet system(Microjet IJK-200s)with a nozzle size of70m m in inner diameter was used with the indium tin oxide (ITO)coated polyethylene terephthalate(PET)?lms as the sub-strates.In this work,the inkjet conditions such as pulse voltage and pulse duration were?xed at75V and67m s,respectively.UV exposure(172nm,10mW/cm2,Ushio UER20-172)was applied to the ITO substrates before printing as the hydrophilic treatment. Films in any patterns could be made by overlapping neighboring spots by a negligible degree.To avoid the environmental turbulence interference on the droplet,the distance between the jet nozzle and the substrate was less than1mm.The macroscopic absorption spectra of the large area?lms(9?9mm)were measured by an absorption spectrometer(Shimadzu,UV-160A).The microscopic images and local absorption spectra of various sites of the inkjet printed spots were evaluated with an optical microscope(Nikon, Eclipse TE2000U)and a multiple channel spectrometer(Ocean Optics,USB2000).The morphology of the inkjet printed NK-1952/ PEDOT:PSS spots were measured by atomic force microscopy (AFM;Keyence VN-8000M/8010M).

To make the organic bulk-hetero photodiodes,the ITO sub-strates were etched by10%of aqua regia(20s)with masks to obtain designed patterns before the UV exposure and inkjet printing. Small area?lms of NK-1952/PEDOT:PSS in the size of1?1mm, consisting of w46overlapped spots were printed onto the ITO patterns as the bulk-hetero layers.After inkjet printing,a thin Al layer was vapor deposited(ULAC,VPC-410,6?10à3Pa)on the top of cyanine dye?lms as the cathode while the ITO behaved as the anode,and thus the bulk heterojunction photodiodes were made. The open-circuit voltage(Voc)between the cathode and anode of the inkjet printed organic bulk-hetero photodiodes was measured by oscilloscope(Tektronix,TDS3032)under the excitation of a passively Q-switched and frequency-doubled Nd:YAG laser(0.5ns, 532nm).The laser beam was injected from the ITO side of the organic photodiodes at the maximum energy and repetition rate of 26m J/pulse and500Hz,respectively.

3.Results and discussion

At the?xed inkjet conditions and PEDO:PSS concentration,the effect of the cyanine dye concentration on J-aggregate formation in inkjet printed?lms was investigated,as shown in Fig.2.In all

H N

(CH2)3(CH2)3

C2H5

SO3SO3H.N(C2H5)3

(a)

(b)

Fig.1.Chemical structures of NK-1952(a),and PEDOT:PSS(b).

T.Nakamichi et al./Dyes and Pigments98(2013)333e338 334

macroscopic absorption spectra shown in Fig.2,a sharp and steep absorption peak at w 541nm could be observed,red-shifted in comparison with the absorption peak at w 504nm of the NK-1952monomer,indicating the formation of J-aggregate,and thus the spectral-resolving capability of photodiodes in this region was ex-pected.To characterize the J-aggregate formation and then the spectral-resolving capability,the index of h was de ?ned as the ratio of the absorbance at 541nm to that at 504nm,which indicated the transition of NK-1952molecules from the monomer to J-aggregate.It could be found that with the increase of dye/polymer ratio from 2.5:1to 10:1,a steadily increase on the peak absorbance at 541nm was observed while the h decreased from 4.2to 3.1.However,in cases of the spin-coated ?lms,the h kept almost constant at 3.7e 3.8when the dye/polymer ratio varied,as shown in Fig.3.The different dependence of h on the dye concentration between the inkjet printed and spin-coated NK-1952/PEDOT:PSS ?lms could be ascribed to the different drying behavior between these two kinds of ?lms.

It should be mentioned that with the increase of dye concen-tration,the viscosity of the ink solution also increased.However,the thickness of the spin-coated ?lms were almost the same,as the optical densities of the ?lms increased proportional to the dye/polymer ratio while the h kept almost constant at w 3.8,indicating that the in ?uence of increasing dye concentration on the drying speed of spin-coated NK-1952/PEDOT:PSS ?lms could be neglected because the h ,which re ?ected the transition of NK-1952molecules from the monomer to J-aggregate,was dependent on the increase of dye concentration in local areas.In contrast,the thickness of the inkjet printed spots increased with the increase of solution vis-cosity,which was decided by the dye concentration.As shown in

Fig.4(A)e (D),with the increase of dye concentration,the spot size decreased from 245m m to 198m m,while the volume of droplets observed near the inkjet nozzle,were found almost unchanged in all cases,at w 300pL.It should also be mentioned that droplet velocity also decreased steadily from 3.1m/s to 2.3m/s,with the increase of dye concentration,indicating a wider spread of the liquid droplet on the ITO surface at lower dye concentration.So,a thinner spot and faster drying-up speed could be expected in case of lower dye concentrations,which resulted in a better J-aggregate formation of the ?lms with a higher h ,as have been reported previously [20].It should also be noted that at the dye/polymer ratio of 2.5:1,the h of the inkjet printed NK-1952/PEDOT:PSS ?lm was w 4.2,even higher than that of the ?lm made by spin-coating,indicating a higher spectral-resolving capability of the inkjet printed photodiodes than that of the photodiodes made by spin-coating.So,2.5:1of dye/polymer ratio was adopted as the opti-mized dye concentration in the following discussions.A further advantage of the lower dye concentration might be the reduction of the ?bril-effect in the ?lms caused by the high dye concentration,which resulted in extra loss in the organic optoelectronic devices,a feature which has been reported previously [24,25].In these con-cerns,investigations on the J-aggregate formation at various local sites in the inkjet printed spots were needed.

The local absorption spectra of various sites inside the inkjet printed spots were obtained by measuring the transmission spectra of the local sites in the spot.As shown in Fig.5,with the aid of a 20m m size pin hole which was tightly placed onto the surface of the spots,the local transmission spectra at various sites of the spots were then calculated.The absorption spectra were obtained as,

Abs ?àlog

T sample

T background

where T sample and T background were the transmission spectra taken inside and outside the spots,respectively.In this work,three observation sites located at the edge,middle envelope and center of the spot were selected and the local absorption spectra obtained were shown in logarithm scale.

As shown in Fig.5,a clear difference between the local ab-sorption spectra at various sites could be observed.It was found that the peak absorbance at w 541nm decreased slightly from the edge to the center,while the h increased sharply from w 3.8to w 6.2,indicating a non-uniform thickness and distribution of the remaining monomer dye molecules in the inkjet printed spots.The AFM cross-section pro ?le of the inkjet printed NK-1952/PEDOT:PSS spot was shown in Fig.6.It could be con ?rmed that a clear coffee-ring structure was formed in the inkjet printed spots,with the thickness at the edge and center found to be w 40nm and w 30nm,respectively.As had been revealed by other research on the “coffee-ring ”effect,it was suggested that during the drying process of the inkjet printed spots,the Marangoni ?ow occurred from the lower to the relatively higher surface tension regions in the liquid spots due to the surface tension gradient,transporting more solutes from the center to the contact line,which enhanced the outward convective ?ow to compensate for the evaporation loss at the periphery [5,26e 28].Thus,a thicker and dye-condensed edge in contrast to the center was observed.It should also be noted that a thinner center region resulted in a higher h and better J-aggregate formation than that of a thicker edge,was also in good accordance with the ten-dency revealed in Fig.2,in which a thinner region resulted in better J-aggregate formation.It was assumed that due to the Marangoni ?ow,the thinner center region dried more rapidly and the J-aggregate formed during this process,resulted in a higher h and better J-aggregate formation than that of a thicker edge.Thus,it

I 541/I 504

Dye/polymer ratio

A b s o r b a n c e (O .D .)

Fig.3.Dependence of peak absorbance and h from the macroscopic absorption spectra on dye/polymer ratio of the NK-1952/PEDOT:PSS ?lms.

A b s o r b a n c e (O .D .)

Wavelength (nm)

Fig.2.Macroscopic absorption spectra of NK-1952/PEDOT:PSS ?lms by inkjet printing at various dye/polymer ratios.

T.Nakamichi et al./Dyes and Pigments 98(2013)333e 338335

was expected that by precisely controlling the inkjet conditions such as solvent composition and temperature,a ?at morphology with uniform aggregate distribution and better spectral-resolving capability might be obtained,resulting in further improvements.

The better J-aggregate formation at the lower cyanine dye concentration also led to signi ?cant improvement on the photo-current properties of organic photodiodes.The open-circuit voltage (Voc)of organic photodiodes based on the dye/polymer ratio of 2.5:1at various input energy was shown in Fig.7.The Voc

increased linearly below the input energy of w 100nJ and the sensitivity,presented in terms of quantum ef ?ciency was as high as 0.13%.In comparison with our previous results that the quantum ef ?ciencies were only 10à6at the higher dye/polymer ratio of 10:1,at least a three orders of magnitude improvement on the sensitivity of organic photodiodes was estimated.It was also suggested to be ascribed to the suppression of the ?bril structures at lower dye concentrations,as shown in Fig.4,which increased the p-n inter-face area inside the bulk-hetero junction and thus reduced the loss of excitons signi ?cantly.

As revealed in the above discussions,lower cyanine concentra-tion and thinner ?lm thickness resulted in higher sensitivity and spectral-resolving capability.For instance,the index h was w 6.2at the center region of inkjet printed spots with the dye/polymer ratio of 2.5:1.However,the optical density of the NK-1952/PEDOT:PSS ?lm at the optimized dye concentration was less than 0.4,indi-cating that more than 60%of the incident beam at 541nm might be transmitted.Thus,there was the necessity to increase the optical density of the NK-1952/PEDOT:PSS ?lm while keeping the h on

Fig.4.Images of inkjet printed spots on ITO substrate at the dye/polymer ratio of (A)2.5:1,(B)5:1,(C)7.5:1,(D)10:1,and (E)spots after stacking 3-layers of spots at the dye/polymer ratio of 2.5:1,and (F)the photodiodes based on overlapped

spots.

Fig.5.(A)Local absorption spectra of inkjet printed NK-1952/PEDOT:PSS spots at various positions and images of local absorption spectra measurement at (B)center,(C)edge,and (D)middle.

H e i g h t (n m )

Horizontal distance m

μFig.6.AFM cross-section pro ?le of stacking spots on ITO substrates.

T.Nakamichi et al./Dyes and Pigments 98(2013)333e 338

336

high level.Recently,sequential inkjet printing of poly(3-hexylthiophene)and phenyl-C61-butyric acid methyl ester blend as OSCs by in-situ stacking of droplets has been reported [29].Concerning the fast drying process of inkjet droplets,sequential stacking of inkjet printed spots might be a feasible way to increase the absorbance without damaging the J-aggregation.Under this aim,a 2nd and 3rd droplets of NK-1952/PEDOT:PSS were deposited onto the 1st inkjet printed spot subsequently with a time interval of 1s.The morphology and AFM cross-section pro ?les of the inkjet printed spots stacked in various layers were shown in Fig.6.It could be found that by stacking the 2nd and 3rd spots,the thickness at the center regions increased linearly as w 60and w 90nm,respectively.The image of the stacked spot is shown in Fig.4(E),which indicated that there was no change on the spot diameter after stacking.So,it might be concluded that when deposited the 2nd droplet onto the top of previous spots,there was no major change on the contact angle of the liquid and the thickness of the stacking spots could be adjusted as designed.

The local absorption spectra of inkjet printed spots at the center regions after stacking 2and 3layers were also measured,as shown in Fig.8.It could be found that after stacking the 2nd and 3rd layer

of NK-1952/PEDOT:PSS,the peak absorbance at 541nm at the center region increased to w 0.79and w 1.25,respectively,absor-bance values which could not be obtained previously by single layer because of the restriction on solution viscosity at high dye and polymer concentrations for droplets ejection.After stacking,although the h at the center regions decreased to 4.1e 4.2,they were still higher than that of the NK-1952/PEDOT:PSS ?lms made by spin-coating.In the example where three layers were stacked vertically,w 1.25of optical density was obtained,corresponding to 5.6%of transmission.Thus,the transmitted excitation light from the active layer might be neglected.Such kind of stacking J-aggregated cyanine dye spots might also be employed as miniaturized and cost-effective narrow-band optical ?lters and it should be noted that by adjusting the temperature of the ink droplet,the drying kinetics of the sequentially stacked spots together with the J-aggregate formation inside the 2nd and 3rd layers might be further controlled and improved.This work is now underway.

4.Conclusions

In summary,the cyanine dye concentration of the inkjet printed ?lms was optimized and the J-aggregate formation in the printed spots investigated by measuring the local absorption.The coffee-ring morphology and the local absorption spectra revealed that the thinner center region of the inkjet printed spots resulted in better J-aggregate formation than that at the edge part.At least three orders of magnitude improvement on the sensitivity of organic photodiodes at lower dye concentration was observed.The optical density of the spots increased linearly by stacking droplets sequentially without major damage to the J-aggregation,indicating the feasibility of these stackable inkjet printed spots as narrow-band ?lters.Acknowledgments

The authors gratefully acknowledge the ?nancial support by the National Natural Science Foundation of China (Nos.51010002,51272231and 51229201),Natural Science Foundation of Zhejiang Province (No.LY12E02004),the Fundamental Research Funds for the Central Universities,and Industrial Technology Research Grant Program in 2007from the New Energy and Industrial Technology Development Organization in Japan.References

[1]Yoshioka Y,Calvert PD,Jabbour GE.Simple modi ?cation of sheet resistivity of

conducting polymeric anodes via combinatorial ink-jet printing techniques.Macromol Rapid Commun 2005;26:238e 46.

[2]Yoshioka Y,Jabbour GE.Inkjet printing of oxidants for patterning

of nanometer-thick conducting polymer electrodes.Adv Mater 2006;18:1307e 12.

[3]Tekin E,Holder E,Kozodaev D,Schubert US.Controlled pattern formation of

poly [2-methoxy-5(20-ethylhexyloxyl)-1,4-phenylenevinylene](MEH-PPV)by ink-jet printing.Adv Funct Mater 2007;17:277e 84.

[4]Chang SC,Liu J,Bharathan J,Yang Y,Onohara J,Kido J.Multicolor organic

light-emitting diodes processed by hybrid inkjet printing.Adv Mater 1999;11:734e 7.

[5]Lim JA,Lee WH,Lee HS,Lee JH,Park YD,Cho K.Self-organization of ink-jet-printed triisopropylsilylethynyl pentacene via evaporation-induced ?ows in a drying droplet.Adv Funct Mater 2008;18:229e 34.

[6]Sirringhaus H,Kawase T,Friend RH,Shimoda T,Inbasekaran M,Wu W,et al.

High-resolution inkjet printing of all-polymer transistor circuits.Science 2000;290:2123e 6.

[7]Park EY,Park JS,Kim TD,Lee KS,Lim HS,Lim JS,et al.High-performance n-type organic ?eld-effect transistors fabricated by ink-jet printing using a C https://www.sodocs.net/doc/8c3405667.html, Electron 2009;10:1028e 31.

[8]Hoth CN,Schilinsky P,Choulis SA,Brabec CJ.Printing highly ef ?cient organic

solar cells.Nano Lett 2008;8:2806e 13.

[9]Hoth CN,Choulis SA,Schilinsky P,Brabec CJ.High photovoltaic performance of

inkjet printed polymer:fullerene blends.Adv Mater 2007;19:3973e

Fig.7.The open-circuit voltage of organic photodiodes based on 2.5:1of dye/polymer ratio by depressing the ?bril structure at various input energy (inset:schematic of the bulk-hetero junction based on NK-1952/PEDOT:PSS).

0.010.1

A b s o r b a n c e (O .D .)

Wavelength (nm)

Fig.8.Local absorption spectra of inkjet printed NK-1952/PEDOT:PSS spots stacked in various layers.

T.Nakamichi et al./Dyes and Pigments 98(2013)333e 338337

[10]Xia YJ,Friend RH.Controlled phase separation of poly?uorene blends via

inkjet printing.Macromolecules2005;38:6466e71.

[11]de Gans BJ,Hoeppener S,Schubert US.Polymer-relief microstructures by

inkjet etching.Adv Mater2006;18:910e4.

[12]van Osch THJ,Perelaer J,de Laat AWM,Schubert US.Inkjet printing of narrow

conductive tracks on untreated polymeric substrates.Adv Mater2008;20:343e5.

[13]Derby B.Printing and prototyping of tissues and scaffolds.Science2012;338:

921e6.

[14]Song K,Jung Y,Kim Y,Kim A,Hwang JK,Sung MM,et al.Solution-processable

tin-doped indium oxide with a versatile patternability for transparent oxide thin?lm transistors.J Mater Chem2011;21:14646e54.

[15]Soltman D,Subramanian V.Inkjet-printed line morphologies and temperature

control of the coffee ring https://www.sodocs.net/doc/8c3405667.html,ngmuir2008;24:2224e31.

[16]Oki Y,Ogawa Y,Yamashita K,Miyazaki M,Maeda M.Integration of optical

pumped dye laser on organic micro?owcytometry chip.Mol Cryst Liq Cryst 2007;463:413e22.

[17]Yang Y,Goto R,Omi S,Yamashita K,Watanabe H,Miyazaki M,et al.

Highly photo-stable dye doped solid-state distributed-feedback(DFB)chan-neled waveguide lasers by a pen-drawing technique.Opt Express2010;18: 22080e9.

[18]Yang Y,Nakamichi T,Yoshioka H,Omi S,Goto R,Watanabe H,et al.Intensity

sensitive organic photodiodes patterned by inkjet method.Mol Cryst Liq Cryst 2011;538:136e42.

[19]Yang Y,Omi S,Goto R,Yahiro M,Era M,Watanabe H,et al.Wavelength

sensitive photodiodes in the visible based on J-type aggregated?lms patterned by inkjet https://www.sodocs.net/doc/8c3405667.html, Electron2011;12:405e10.[20]Yang Y,Imaoka H,Yamashita K,Kamogawa N,Watanabe H,Miyazaki M,et al.

Patterning on cyanine-dye-doped conductive polymer?lms by ink jet method.Jpn J Appl Phys2010;49:010204.

[21]Bel?eld KD,Bondar MV,Hernandez FE,Przhonska OV,Yao S.Two-photon

absorption of a supramolecular pseudoisocyanine J-aggregate assembly.

Chem Phys2006;320:118e24.

[22]Wurthner F,Yao S.Dipolar dye aggregates:a problem for nonlinear optics,but a

chance for supramolecular chemistry.Angew Chem Int Ed2000;39:1978e81.

[23]Chu OY,Shuangjun CJ,Bo C,Gi X.Aggregation of azo dye Orange I induced by

polyethylene glycol in aqueous solution.Colloids Surf A2007;301:346e51.

[24]Oda M,Hirata K,Inoue T,Obara Y,Fujimura T,Tani T.Strong exciton-photon

[25]Oda M,Obara Y,Saito K,Higashi K,Tani T.Fabrication,characterization and its

local re?ection properties of a metal-mirror microcavity with high concen-trated PIC J-aggregates.Phys Procedia2010;3:1615e20.

[26]Deegan RD,Bakajin O,Dupont TF,Huber G,Nagel SR,Witten TA.Capillary?ow

as the cause of ring stains from dried liquid drops.Nature1997;389:827e9.

[27]Kajiya T,Monteux C,Narita T,Lequeux F,Doi M.Contact-line recession leaving

a macroscopic polymer?lm in the drying droplets of water-poly(N,N-

dimethylacrylamide)(PDMA)https://www.sodocs.net/doc/8c3405667.html,ngmuir2009;25:6934e9.

[28]Li YC,Fu C,Xu J.Topography of thin?lm formed by drying silver nanoparticle

dispersion droplets.Jpn J Appl Phys2007;46:2807e10.

[29]Eom SH,Park H,Mujawar SH,Yoon SC,Kim SS,Na SI,et al.High ef?ciency

polymer solar cells via sequential inkjet-printing of PEDOT:PSS and P3HT: PCBM inks with https://www.sodocs.net/doc/8c3405667.html, Electron2010;11:1516e22.

T.Nakamichi et al./Dyes and Pigments98(2013)333e338 338

Stackable spectral-sensitive conductive films based on cyanine aggregates via an inkjet method

相关文档

最新文档