Alkyl Chain Effect and Photoelectric Properties of D-A-D Structural Solution Processable Organic Small Molecules

doi:10.3969/j.issn.0251-0790.2012.01.031

Abstract

Abstract: Three novel solution processable organic small molecules, TPT-N, TPT-S and TPT-D with a Donor-Acceptor-Donor(D-A-D) structure based on thiophene donor unit and 2-pyran-4-ylidenemalononitrile(PM) acceptor unit, were designed and synthesized. Effect of alkyl chain number on the solubility, photophysical properties(absorption characteristic), thermal stability and photoelectric properties of the molecules were investigated. The results indicate that with the alkyl chain increasing the solubility and film-forming pro-perties of the molecules increase, and the absorption spectra of the organic small molecules are red-shifted in solutions and the absorption bands in films become narrow. Moreover, the highest occupied molecular orbital(HOMO) energy levels also increase with the alkyl chain of the molecules increasing. Bulk heterojunction structural solar cells with a device structure of ITO/PEDOT∶PSS/D-A-D∶PCBM/LiF/Al based on the D-A-D organic small molecules as the donor,(6,6)-phenyl C₆₁-butyric acid methyl ester(PCBM) as the acceptor were fabricated. It is found that the device based on TPT-S which has a single alkyl chain on the thiophene unit has a relatively high power conversion efficiency(PCE). The research results confirm that the alkyl chain number is one of the most important effects that influence the properties of the materials and device perfor-mance as for D-A-D organic small molecular solar cell materials.

Key words: Donor-Acceptor-Donor(D-A-D), Organic small molecule, Alkyl chain, Solar cell

CLC Number:

O631

TrendMD:

LI Qiang, LIU Zhao-Yang, LIU Lei-Jing, LI Zai-Fang, CHENG Wei-Dong, LI Hui, LI Peng-Fei, LI Zi-Jian, GUAN Chang-Jian, JIA Yi-Long, TIAN Wen-Jing. Alkyl Chain Effect and Photoelectric Properties of D-A-D Structural Solution Processable Organic Small Molecules[J]. Chem. J. Chinese Universities, 2012, 33(01): 182.

References

[1] ZHANG Jian-Feng(张剑锋), ZHOU Hua-Xing(周华兴), YOU Wei(尤伟). J. Hefei University, Natural Sciences(合肥大学学报, 自然科学版)[J], 2009, 19(4): 1-7 [2] Dong B., Yao Q. H., Wang K. Z., Jin L. P., Huang C. H.. Chem. Res. Chinese Universites[J], 2002, 18(4): 469-470 [3] Xue J. G., Rand B. P., Uchida S. Forrest S. R.. Adv. Mater.[J], 2005, 17: 66-71 [4] Walker B., Tamayo A. B., Dang X. D., Zalar P., Seo P. H., Garcia A., Tantiwiwat M., Nguyen T. Q.. Adv. Funct. Mater.[J], 2009, 19: 3063-3069 [5] Li Z. F., Dong Q. F, Li Y. W., Xu B., Tian W. J.. J. Mater. Chem.[J], 2011, 21: 2159-2168 [6] Li Z. F., Pei J. N., Li Y. W., Xu B., Deng M., Liu Z. Y., Li H., Lu H. G., Li Q., Tian W. J.. J. Phys. Chem. C[J], 2010, 114: 18270-18278 [7] Zhang S. M., Fan H. J., Liu Y., Zhao G. J., Li Q. K., Li Y. F., Zhan X. W.. J. Polym. Sci. Part A: Polym. Chem.[J], 2009, 47: 2843-2852 [8] Li Z. F, Pei J. N.,Li Y. W., Xu B., Deng M., Liu Z. Y., Li H., Lu H. G., Li Q.. J. Phys. Chem. C[J], 2010, 114: 18270-18278 [9] Zhao G. J., Wu G. L., He C., Zhang J., He Q. G., Chen X. M., Li Y. F.. J. Phys.Chem. C[J], 2009, 113: 2636-2642 [10] Li Y. W., Xue L. L., Li H., Li Z. F., Xu B., Wen S. P., Tian W. J.. Macromolecules[J], 2009, 42: 4491- 4499 [11] Pommerehne J., Vestweber H., Guss W., Mahrt R. F., Bässler H., Porsch M., Daub J.. Adv. Mater.[J], 1995, 7: 551-554 [12] Leclerc N., Michaud A., Sirois K., Morin J. F., Leclerc M.. Adv. Funct. Mater.[J], 2006, 16: 1694- 1704 [13] Thompson B. C., Kim Y. G., McCarley T. D., Reynolds J. R.. J. Am. Chem. Soc.[J], 2006, 128: 12714- 12725 [14] Scharber M. C., Mühlbacher D., Koppe M., Denk P., Waldauf C., Heeger A. J., Brabec C. J.. Adv. Mater.[J], 2006, 18: 789-794 [15] Wen S. P., Pei J. N., Zhou Y. H., Li P. F., Xue L. L., Li Y. W., Xu B., Tian W. J.. Macromolecules[J], 2009, 42: 4877-4984