Bis(2-phenylpyridine)(2,2'-bithiazole)iridium(Ⅲ) Hexafluorophosphate: Synthesis and Application in Neutral/Warm White Light-emitting Diodes†

doi:10.7503/cjcu20170608

Abstract

Abstract:

A novel orange cationic organic iridium(Ⅲ) complex, [(ppy)₂Ir(btz)]PF₆, was synthesized using IrCl₃·3H₂O as iridium(Ⅲ) source, 2-phenylpyridine(ppy) as main ligand and 2,2'-bithiazole(btz) as auxiliary ligand. After the mixture of aforementioned three compounds was refluxed in glycol for 24 h, an ion exchange reaction was made with an aqueous solution of NH₄PF₆ for providing target complex. The correlated color temperature(CCT) of white light-emitting diodes(WLEDs) fabricated by 455 nm-emitting blue GaN chip and Y₃Al₅O₁₂∶Ce³⁺(YAG∶Ce, 6.0% mass ratio to silicone) obviously declined when the complex was blended in silicone and also used in these WLEDs. Before the complex was used, CCT of the YAG∶Ce-based WLED was 7133 K, the luminous efficiency(η_L) was 137.1 lm/W, the color rendering index(CRI) was 79.9, and the CIE(Commission International de I'Eclairage) value was (0.31, 0.31). When [(ppy)₂Ir(btz)]PF₆ was used in aforementioned WLEDs at 1.0%, 1.5% and 2.0% blending concentrations, CCT successively decreased to 5645 K(cold white light), 4072 K(neutral white light) and 3161 K(warm white light), the corresponding η_L values were 102.1, 79.1 and 66.6 lm/W, CRI were 81.9, 77.3 and 70.0, CIE values were (0.33, 0.31), (0.36, 0.33) and(0.42, 0.38), respectively. The results show that [(ppy)₂Ir(btz)]PF₆ is a promising orange phosphor candidate for fabricating efficient neutral/warm WLEDs.

Key words: Cationic organic iridium(Ⅲ) complex;, White light-emitting diode, Photoluminescence, GaN, YAG∶Ce;

CLC Number:

O614
O621.22

TrendMD:

SUN Riyong,CHEN Zeyu,YE Yanchun,CHEN Mingxian,TANG Huaijun,WANG Kaimin,WANG Zhengliang. Bis(2-phenylpyridine)(2,2'-bithiazole)iridium(Ⅲ) Hexafluorophosphate: Synthesis and Application in Neutral/Warm White Light-emitting Diodes^†[J]. Chem. J. Chinese Universities, 2018, 39(5): 869.

Figures/Tables 8

Scheme 1 Synthetic route and the chemical structure of [(ppy)2Ir(btz)]PF6

Fig.1 Normalized excitation(λem=584 nm) and emission(λex=455 nm) spectra of [(ppy)2Ir(btz)]PF6 blended in silicone at 6.0%, normalized electroluminescent(EL) emission spectrum of GaN and photoluminescent(PL) emission spectrum of YAG∶Ce

Fig.2 TG curve of [(ppy)2Ir(btz)]PF6

Fig.3 Temperature-dependent PL spectra(λex=455 nm) of [(ppy)2Ir(btz)]PF6 Temperature(℃) from a to i: 20, 40, 60, 80, 100, 120, 140, 160, 180.

Fig.4 Relative photoluminescent intensity as a function of temperature of [(ppy)2Ir(btz)]PF6(A) and ln[(I0/I)-1]-1/T phot(B)

Fig.5 Normalized emission spectra of blue GaN-based WLEDs using YAG∶Ce(6.0%) and [(ppy)2Ir·(btz)]PF6(0, 1.0%, 1.5% and 2.0%) as phosphors blended in silicone at different concentrations

Table 1 Performances of the blue GaN-based WLEDs fabricated using YAG∶Ce and [(ppy)2Ir(btz)]PF6 as phosphors at different blending concentrations with 20 mA forward current

WLED	Blending concentration(mass fraction, %)		Luminous efficiency/ (lm·W^-1)	CRI	CCT/K	λ_{em, max}/nm	CIE(x,y)
WLED	YAG∶Ce		Luminous efficiency/ (lm·W^-1)	CRI	CCT/K	λ_{em, max}/nm	Complex
Ⅰ	6.0	0.0	137.1	79.9	7133	457,553	(0.31,0.31)
Ⅱ	6.0	1.0	102.1	81.9	5645	458,581	(0.33,0.31)
Ⅲ	6.0	1.5	79.1	77.3	4072	459,583	(0.36,0.33)
Ⅳ	6.0	2.0	66.6	70.0	3161	460,585	(0.42,0.38)

Fig.6 CIE chromaticity coordinates of blue GaN-based WLEDs using YAG∶Ce(6.0%) and [(ppy)2Ir(btz)]PF6(0, 1.0%, 1.5% and 2.0%) as phosphors blended in silicone at different concentrations Note:Insets: photographs of the WLEDs in working state.

References 36

[1]	Pimputkar S., Speck J.S., DenBaars S. P., Nakamura S., Nat. Photonics, 2009, 3, 180—182
[2]	Tsao J.Y., Crawford M. H., Coltrin M. E., Fischer A. J., Koleske D. D., Subramania G. S., Wang G. T., Wierer J. J., Karlicek Jr. R. F., Adv. Opt. Mater., 2014, 2(9), 809—836
[3]	Chen L., Lin C.C., Yeh C. W., Liu R. S., Materials, 2010, 3(3), 2172—2195
[4]	Sajjad M.T., Manousiadis P. P., Chun H., Vithanage D. A., Rajbhandari S., Kanibolotsky A. L., Faulkner G., O'Brien D., Skabara P. J., Samuel I. D. W., Turnbull G. A., ACS Photonics, 2015, 2(2), 194—199
[5]	Zhao C., Zhu D., Ma M., Han T., Tu M., [J]. Alloys Compd., 2012, 523, 151—154
[6]	Kwak H.H., Kim S. J., Park Y. S., Yoon H. H., Park S. J., Choi H. W., Mol. Cryst. Liq. Cryst., 2009, 513, 106—113
[7]	Jang H.S., Im W. B., Lee D. C., Jeon D. Y., Kim S. S., [J]. Lumin., 2007, 126, 371—377
[8]	Lin C.C., Zheng Y. S., Chen H. Y., Ruan C. H., Xiao G. W., Liu R. S., [J]. Electrochem. Soc., 2010, 157, H900—H903
[9]	Kuo T.W., Liu W. R., Chen T. M., Opt. Express, 2010, 18(8), 8187—8192
[10]	Ruan J., Xie R.J., Hirosaki N., Takeda T., [J]. Am. Ceram. Soc., 2011, 94(2), 536—542
[11]	Setlur A.A., Lyons R. J., Murphy J. E., Kumar N. P., Kishore M. S., ECS [J]. Solid State Sci. Tech., 2013, 2, R3059—R3070
[12]	Zhou Q., Zhou Y.Y., Liu Y., Luo L. J., Wang Z. L., Peng J. H., Yan J., Wu M. M., J. Mater. Chem. C, 2015, 3(13), 3055—3059
[13]	Kim S., Kim T., Kang M., Kwak S.K., Yoo T. W., Park L. S., Yang I., Hwang S., Lee J. E., Kim S. K., Kim S. W., [J]. Am. Chem. Soc., 2012, 134(8), 3804—3809
[14]	Shao G., Zhang N., Lin D., Feng K., Cao R., Gong M., [J]. Lumin., 2013, 138, 195—200
[15]	Cheng H., Zhao X., Gao H., Zhu H., Jiang L., Ling Q., Chem. J. Chinese Universities, 2015, 36(1), 41—47
	陈鸿, 赵璇, 高慧, 朱海娣, 姜丽红, 凌启淡. 高等学校化学学报, 2015, 36(1), 41—47
[16]	Meng G., Chen Z., Tang H., Liu Y., Wei L., Wang Z., New J.Chem., 2015, 39, 9535—9542
[17]	Yang H., Meng G., Zhou Y., Tang H., Zhao J., Wang Z., Materials, 2015, 8, 6105—6116
[18]	Tang H., Meng G., Chen Z., Wang K., Zhao Q., Wang Z., Materials, 2017, 10, 657
[19]	Tang H., Meng G., Chen Z., Liu Y., Wei L., Wang Z., J. Mater. Sci.: Mater. Electron., 2015, 26(5), 2824—2829
[20]	Sun C.Y., Wang X. L., Zhang X., Qin C., Li P., Su Z. M., Zhu D. X., Shan G. G., Shao K. Z., Wu H., Li [J]., Nat. Commun., 2013, 4, 2717
[21]	Niklaus L., Dakhil H., Kostrzewa M., Coto P.B., Sonnewald U., Wierschem A., Costa R. D., Mater. Horiz., 2016, 3, 340—347
[22]	Xiang H.F., Yu S. C., Che C. M., Lai P. T., Appl. Phys. Lett., 2003, 83, 1518—1520
[23]	Martino D.D., Beverina L., Sassi M., Brovelli S., Tubino R., Meinardi F., Sci. Rep., 2014, 4, 4400
[24]	Findlay N.J., Bruckbauer J., Inigo A. R., Breig B., Arumugam S., Wallis D. J., Martin R. W., Skabara P. [J]., Adv. Mater., 2014, 26(43), 7290—7294
[25]	Zhang C., Heeger A.J., [J]. Appl. Phys., 1998, 84, 1579—1582
[26]	Zhao X., Hou Z., Wang B., Shen Q., Jia H., Zhang A., Liu X., Xu B., Res. Chem. Intermed., 2017, 43, 4129—4143
[27]	Ma D., Tsuboi T., Qiu Y., Duan L., Adv. Mater., 2017, 29(3), 1603253
[28]	Hu T., He L., Duan L., Qiu Y., [J]. Mater. Chem., 2012, 22, 4206—4215
[29]	Costa R.D., Ortí E., Bolink H. J., Monti F., Accorsi G., Armaroli N., Angew. Chem. Int. Ed., 2012, 51(33), 8178—8211
[30]	Ulbricht C., Beyer B., Friebe C., Winter A., Schubert U.S., Adv. Mater., 2009, 21, 4418—4441
[31]	Tang H., Li Y., Chen Q., Chen B., Qiao Q., Yang W., Wu H., Cao Y., Dyes Pigments, 2014, 100, 79—86
[32]	Lo K.K. W., Li S. P. Y., Zhang K. Y., New [J]. Chem., 2011, 35, 265—287
[33]	Chen Z., Meng G., Tang H., Ye Y., Sun R., Chen M., Wang K.M., New [J]. Chem., 2017, 41, 8312—8319
[34]	Yang Y., Zhao Q., Feng W., Li F., Chem. Rev., 2013, 113, 192—270
[35]	Li H., Zhao R., Jia Y., Sun W., Fu J., Jiang L., Zhang S., Pang R., Li C., ACS Appl.Mater. Interfaces, 2014, 6(5), 3163—3169
[36]	Setlur A.A., Radkov E. V., Henderson C. S., Her J. H., Srivastava A. M., Karkada N., Kishore M. S., Kumar N. P., Aesram D., Deshpande A., Kolodin B., Grigorov L. S., Happek U., Chem. Mater., 2010, 22, 4076—4082