Highly emissive H-aggregates or aggregation-induced emission quenching? the photophysics of all-trans para-distyrylbenzene

Journal of Physical Chemistry Letters

Volumn 4, Issue 16, 2013, Pages 2686-2697

  Gierschner, Johannes ^a,b   Lüer, Larry ^a,b   Milián Medina, Begoña ^a   Oelkrug, Dieter ^b   Egelhaaf, Hans Joachim ^b,c  

^a INSTITUTO MADRILEÑO DE ESTUDIOS AVANZADOS EN NANOCIENCIA IMDEA NANOCIENCIA   (Spain)

^b UNIVERSITY OF TÜBINGEN   (Germany)

^c BELECTRIC OPV GmbH   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

AGGREGATION-INDUCED EMISSIONS; H-AGGREGATES; PHOTOPHYSICS; POLARIZATION EFFECT; POLYCRYSTALLINE SAMPLES;

QUENCHING;

AGGREGATES;

EID: 84882368595     PISSN: None     EISSN: 19487185     Source Type: Journal    
DOI: 10.1021/jz400985t     Document Type: Review

References (90)

1. Organic Electronics and Optoelectronics. Chem. Rev. 2010, 107, 923-1386.
2. Materials for Electronics. Chem. Rev. 2010, 110, 1-574.
3. Organic Photovoltaics. Acc. Chem. Res. 2009, 42, 1689-1857.
4. Green, M. A.; Emery, K.; Hishikawa, Y.; Warta, W.; Dunlop, E. D. Solar Cell Efficiency Tables Prog. Photovolt: Res. Appl. 2012, 20, 606-614
5. An, B.-K.; Gierschner, J.; Park, S. Y. π-Conjugated Cyanostilbene Derivatives: A Unique Self-Assembly Motif for Molecular Nanostructures with Enhanced Emission and Transport Acc. Chem. Res. 2012, 45, 544-554
6. Varghese, S.; Das, S. Role of Molecular Packing in Determining Solid-State Optical Properties of π-Conjugated Materials J. Phys. Chem. Lett. 2011, 2, 863-873
7. Varghese, S.; Park, S. K.; Casado, S.; Fischer, R.; Resel, R.; Milián-Medina, B.; Wannemacher, R.; Park, S. Y.; Gierschner, J. Stimulated Emission Properties of Sterically Modified Distyrylbenzene-Based H-Aggregate Single Crystals J. Phys. Chem. Lett. 2013, 4, 1597-1602
8. Wu, C. C.; DeLong, M. C.; Vardeny, Z. V.; Ferraris, J. P.; Gutierrez, J. J. Structural and Optical Studies of Distryrylbenzene Single Crystals Synth. Met. 2003, 137, 939-941
9. Van Hutten, P. F.; Wildemann, J.; Meetsma, A.; Hadziioannou, G. Molecular Packing in Unsubstituted Semiconducting Phenylenevinylene Oligomer and Polymer J. Am. Chem. Soc. 1999, 121, 5910-5918
10. Granier, T.; Thomas, E. L.; Gagnon, D. R.; Karasz, F. E.; Lenz, R. W. Structure Investigation of Poly(p-Phenylene Vinylene) J. Polym. Sci., Part B: Polym. Phys. 1986, 24, 2793-2804
11. Baker, K. N.; Fratini, A. V.; Resch, T.; Knachel, H. C.; Adams, W. W.; Socci, E. P.; Farmer, B. L. Crystal Structures, Phase Transitions and Energy Calculations of Poly(p-Phenylene) Oligomers Polymer 1993, 34, 1571-1587
12. Porzio, W.; Destri, S.; Mascherpa, M.; Brükner, S. Structual Aspects of Oligothienyl Series from X-ray Powder Diffraction Data Acta Polym. 1993, 44, 266-272
13. Siegrist, T.; Fleming, R. M.; Haddon, R. C.; Laudise, R. A.; Lovinger, A. J.; Katz, H. E.; Bridenbaugh, P.; Davis, D. D. The Crystal Structure of the High-Temperature Polymorph of α-Hexathienyl (α-6T/HT) J. Mater. Res. 1995, 10, 2170-2173
14. Siegrist, T.; Kloc, C.; Laudise, R. A.; Katz, H. E.; Haddon, R. C. Crystal Growth, Structure, and Electronic Band Structure of α-4T Polymorphs Adv. Mater. 1998, 10, 379-382
15. Antolini, L.; Horowitz, G.; Kouki, F.; Garnier, F. Polymorphism in Oligothiophenes with an Even Number of Thiophene Subunits Adv. Mater. 1998, 10, 382-385
16. Horowitz, G.; Bachet, B.; Yassar, A.; Lang, P.; Demanze, F.; Fave, J.-L.; Garnier, F. Growth and Characterization of Sexithiophene Single Crystals Chem. Mater. 1995, 7, 1337-1341
17. Holmes, D.; Kumaraswamy, S.; Matzger, A. J.; Vollhardt, K. P. C. On the Nature of Nonplanarity in the [N]Phenylenes Chem.-Eur. J. 1999, 5, 3399-3412
18. Oelkrug, D.; Egelhaaf, H.-J.; Gierschner, J.; Tompert, A. Electronic Deactivation in Single Chains, Nano-Aggregates and Ultrathin Films of Conjugated Oligomers Synth. Met. 1996, 76, 249-253
19. Shimizu, M.; Himaya, T. Organic Fluorophores Exhibiting Highly Efficient Photoluminescence in the Solid State Chem. Asian J. 2010, 5, 1516-1531
20. Spano, F. C. The Spectral Signatures of Frenkel Polarons in H- and J-Aggregates Acc. Chem. Res. 2010, 43, 429-439
21. Spano, F. C. The Fundamental Photophysics of Conjugated Oligomer Herringbone Aggregates J. Chem. Phys. 2003, 118, 981-994
22. Spano, F. C. Excitons in Conjugated Oligomer Aggregates, Films and Crystals Annu. Rev. Phys. Chem. 2006, 57, 217-243
23. Wang, H.; Li, F.; Gao, B.; Xie, Z.; Liu, S.; Wang, C.; Hu, D.; Shen, F.; Xu, Y.; Shang, H. Doped Organic Crystals with High Efficiency, Color-Tunable Emission toward Laser Application Cryst. Growth Des. 2009, 9, 4945-4950
24. Yoon, S.-J.; Chung, J. W.; Gierschner, J.; Kim, K. S.; Choi, M.-G.; Kim, D.; Park, S. Y. Multi-Stimuli Two-Color Luminescence Switching via Different Slip-Stacking of Highly Fluorescent Molecular Sheets J. Am. Chem. Soc. 2010, 132, 13675-13683
25. Stampfl, J.; Tasch, S.; Leising, G.; Scherf, U. Quantum Efficiencies of Electroluminescent Poly(para -phenylenes) Synth. Met. 1995, 71, 2125-2128
26. Kabe, R.; Nakanotani, H.; Sakanoue, T.; Yahiro, M.; Adachi, C. Effect of Molecular Morphology on Amplified Spontaneous Emission of Bis-styrylbenzene Derivatives Adv. Mater. 2009, 21, 4034-4038
27. Yoon, S.-J.; Park, S. Y. Polymorphic and Mechanochromic Luminescence Modulation in the Highly Emissive Dicyanodistyrylbenzene Crystal: Secondary Bonding Interaction in Molecular Stacking Assembly J. Mater. Chem. 2011, 21, 8338-8346
28. Egelhaaf, H.-J.; Gierschner, J.; Oelkrug, D. Characterization of Oriented Oligo- (phenylenevinylene) Films and Nano-Aggregates by UV/Vis-Absorption and Fluorescence Spectroscopy Synth. Met. 1996, 83, 221-226
29. Gierschner, J.; Egelhaaf, H.-J.; Oelkrug, D. Absorption, Fluorescence, and Light Scattering of Oligothiophene and Oligophenylenevinylene Nanoaggregates Synth. Met. 1997, 84, 529-530
30. Egelhaaf, H.-J.; Brun, M.; Reich, S.; Oelkrug, D. Luminescence and Photoconductivity Studies on Bonding, Mobility and Electronic Deactivation in Submonolayers and Thin Films of Distyrylbenzene J. Mol. Struct. 1992, 267, 297-302
31. Oelkrug, D.; Haiber, J.; Lege, R.; Stauch, H.; Egelhaaf, H.-J. Temporal Stability of Vapor-Deposited Molecular Films as Studied by Laser Light Scattering Thin Solid Films 1996, 284-285, 581-584
32. Gierschner, J.; Egelhaaf, H.-J.; Oelkrug, D.; Müllen, K. Electronic Deactivation and Energy Transfer in Doped Oligophenylenevinylene Nanoparticles J. Fluoresc. 1998, 8, 37-44
33. Oelkrug, D.; Tompert, A.; Gierschner, J.; Egelhaaf, H.-J.; Hanack, M.; Hohloch, M.; Steinhuber, E. Tuning of Fluorescence Yields in Films and Nanoparticles of Oligophenylenevinylenes J. Phys. Chem. B 1998, 102, 1902-1907
34. Oelkrug, D.; Gierschner, J.; Egelhaaf, H.-J.; Lüer, L.; Tompert, A.; Müllen, K.; Stalmach, U.; Meier, H. Evolution of Optical Absorption from Small Oligomers to Ideally Conjugated PPV and MEH-PPV Oligomers Synth. Met. 2001, 121, 1693-1694
35. Schweikhart, K.-H.; Hohloch, M.; Steinhuber, E.; Hanack, M.; Lüer, L.; Gierschner, J.; Egelhaaf, H.-J.; Oelkrug, D. Highly Luminescent Oligo(phenylenevinylene) Films: The Stereochemical Approach Synth. Met. 2001, 121, 1641-1642
36. Gierschner, J.; Mack, H.-G.; Lüer, L.; Oelkrug, D. Fluorescence and Absorption Spectra of Oligophenylenevinylenes: Vibronic Coupling, Band Shapes and Solvatochromism J. Chem. Phys. 2002, 116, 8596
37. Egelhaaf, H.-J.; Gierschner, J.; Oelkrug, D. Polarizability Effects and Energy Transfer in Quinquethiophene Doped Bithiophene and OPV Films Synth. Met. 2002, 127, 221-227
38. Gierschner, J.; Egelhaaf, H.-J.; Oelkrug, D.; Botchway, S.; Parker, A. W. Time-Resolved Fluorescence Spectroscopy on Single Oligophenylenevinylene Nanoparticles Tech. Rep.-Counc. Cent. Lab. Res. Counc. 2004, 131-133
39. Gierschner, J.; Oelkrug, D. Optical Properties of Oligophenylenevinylenes. Encyclopedia of Nanoscience and Nanotechnology; Nalwa, H., Ed.; American Scientific Publishers: Valencia, CA, 2004; Vol. 8, pp 219-238.
40. Gierschner, J.; Ehni, M.; Egelhaaf, H.-J.; Milián Medina, B.; Beljonne, D.; Benmansour, H.; Bazan, G. C. Solid State Optical Properties of Linear Polyconjugated Molecules: π-Stack Contra Herringbone J. Chem. Phys. 2005, 123, 144914
41. Srinivasan, G.; Villanueva-Garibay, J. A.; Müller, K.; Oelkrug, D.; Milián Medina, B.; Beljonne, D.; Cornil, J.; Wykes, M.; Viani, L.; Gierschner, J. Dynamics of Guest Molecules in PHTP Inclusion Compounds as Probed by Solid-State NMR and Fluorescence Spectroscopy Phys. Chem. Chem. Phys. 2009, 11, 4996-5009
42. Oelkrug, D.; Reich, S.; Wilkinson, F.; Leicester, P. A. Photoionization on Insulator Surfaces. Diffuse Reflectance Laser Flash Photolysis of Distyrylbenzenes Adsorbed on Silica and Alumina J. Phys. Chem. 1991, 95, 269-274
43. Marri, E.; Pannacci, D.; Galiazzo, G.; Mazzucato, U.; Spalletti, A. Effect of the Nitrogen Heteroatom on the Excited State Properties of 1,4-Distyrylbenzene J. Phys. Chem. A 2003, 107, 11231-11238
44. Ginocchietti, G.; Galiazzo, G.; Mazzucato, U.; Spalletti, A. Competitive Radiative and Reactive Relaxation Channels in the Excited State Decay of Some Thio-Analogues of EE-Distyrylbenzene Photochem. Photobiol. Sci. 2005, 4, 547-553
45. Ginocchietti, G.; Cecchetto, E.; De Cola, L.; Mazzucato, U.; Spalletti, A. Photobehaviour of Thio-Analogues of Stilbene and 1,4-Distyrylbenzene Studied by Time-Resolved Absorption Techniques Chem. Phys. 2008, 352, 28-34
46. Wu, C. C.; Korovyanko, O. J.; DeLong, M. C.; Vardeny, Z. V.; Gutierrez, J. J.; Ferraris, J. P. Optical Studies of Distyrylbenzene Single Crystals Synth. Met. 2003, 139, 735-738
47. Wu, C. C.; Ehrenfreund, E.; Gutierrez, J. J.; Ferraris, J. P.; Vardeny, Z. V. Apparent Vibrational Side Bands in π-Conjugated Systems: The Case of Distyrylbenzene Phys. Rev. B 2005, 71, 081201
48. Lim, S.-H.; Bjorklund, T. G.; Bardeen, C. J. Characterization of Individual Submicron Distyrylbenzene Aggregates Using Temperature-Dependent Picosecond Fluorescence and Atomic Force Microscopy J. Phys. Chem. B 2004, 108, 4289-4295
49. Colaneri, N. F.; Bradley, D. D. C.; Friend, R. H.; Burn, P. L.; Holmes, A. B.; Spangler, C. W. Photoexcited States in Poly(p-Phenylene Vinylene): Comparison with trans, trans-Distyrylbenzene, a Model Oligomer Phys. Rev. B 1990, 42, 11670-11681
50. Vasil'eva, I. A.; Voitova, N. A.; Nurmukhametov, R. N. Effect of the Fluorine Substitution in Ethyl Groups of 1,4-Distyrylbenzene on the Fine Structure Fluorescence and Fluorescence Excitation Spectra Opt. Spectrosc. 2012, 112, 443-452
51. For the precise determination of vertical and adiabatic transition energies from the experimental spectra, see: Gierschner, J.; Cornil, J.; Egelhaaf, H.-J. Optical Bandgaps of π-Conjugated Organic Materials at the Polymer Limit: Experiment and Theory Adv. Mater. 2007, 19, 173-191
52. Aloshyna, M.; Milián Medina, B.; Poulsen, L.; Moreau, J.; Beljonne, D.; Cornil, J.; Di Silvestro, G.; Cerminara, M.; Meinardi, F.; Tubino, R.; Detert, H.; Schrader, S.; Egelhaaf, H.-J.; Botta, C.; Gierschner, J. Oligophenylenevinylenes in Spatially Confined Nanochannels: Monitoring Intermolecular Interactions by UV/Vis and Raman Spectroscopy Adv. Funct. Mater. 2008, 18, 915-921
53. Rumi, M.; Barlow, S.; Wang, J.; Perry, J. W.; Marder, S. R. Two-Photon Absorbing Materials and Two-Photon-Induced Chemistry Adv. Polym. Sci. 2008, 213, 1-95, and citations therein
54. Sandros, K.; Sundahl, M.; Wennerström, O.; Norinder, U. Cis-Trans Photoisomerization of a p -Styrylstilbene, a One- and Twofold Adiabatic Process J. Am. Chem. Soc. 1990, 112, 3082-3086
55. Sundahl, M.; Wennerström, O.; Sandros, K.; Arai, T.; Tokumaru, K. Triplet State Z/E Isomerization of a p -Styrylstilbene, a Partly Adiabatic Process J. Phys. Chem. 1990, 94, 6731-6734
56. Takeuchi, S.; Ruhman, S.; Tsuneda, T.; Chiba, M.; Taketsugu, T.; Tahara, T. Spectroscopic Tracking of Structural Evolution in Ultrafast Stilbene Photoisomerization Science 2008, 322, 1073-1077
57. Kovalenko, S. A.; Dobryakov, A. L.; Ioffe, I.; Ernsting, N. P. Evidence for the Phantom State in Photoinduced cis-trans Isomerization of Stilbene Chem. Phys. Lett. 2010, 493, 255-258
58. Bhongale, C. J.; Chang, C.-W.; Lee, C.-S.; Diau, E. W.-G.; Hsu, C.-S. Relaxation Dynamics and Structural Characterization of Organic Nanoparticles with Enhanced Emission J. Phys. Chem. B 2005, 109, 13472-13482
59. Hsu, F.-C.; Lin, S. H.; Wang, J.-K. Excited-State Dynamics of trans,trans-Distyrylbenzene: A Femtosecond Transient Absorption Study Chem. Phys. Lett. 2005, 411, 103-107
60. Hsu, F.-C.; Hayashi, M.; Wang, H.-W.; Lin, S. H.; Wang, J.-K. Excited-State Dynamics of trans, trans -Distyrylbenzene: Transient Anisotropy and Excitation Energy Dependence J. Phys. Chem. A 2007, 111, 759-763
61. Seixas de Melo, J.; Pina, J.; Burrows, H. D.; Di Paolo, R. E.; Maçanita, A. L. Electronic Spectral and Photophysical Properties of some p-Phenylenevinylene Oligomers in Solution and Thin Films Chem. Phys. 2006, 330, 449456
62. Di Paolo, R. E.; Seixas de Melo, J.; Pina, J.; Burrows, H. D.; Morgado, J.; Maçanita, A. L. Conformational Relaxation of p-Phenylenevinylene Trimers in Solution Studied by Picosecond Time-Resolved Fluorescence ChemPhysChem 2007, 8, 2657-2664
63. Lanzani, G.; Nisoli, M.; Magni, V.; De Silvestri, S.; Barbarella, G.; Zambianchi, M.; Tubino, R. Femtosecond Spectral Relaxation of a-Conjugated Hexamethylsexithiophene in Solution Phys. Rev. B 1995, 51, 13770-13773
64. Wong, K. S.; Wang, H.; Lanzani, G. Ultrafast Excited-State Planarization of the Hexamethylsexithiophene Oligomer Studied by Femtosecond Time-Resolved Photoluminescence Chem. Phys. Lett. 1998, 288, 59-64
65. Kasha, M. Relation Between Exciton Bands and Conduction Bands in Molecular Lamellar Systems Rev. Mod. Phys. 1959, 31, 162-169
66. Gierschner, J.; Huang, Y.-S.; Van Averbeke, B.; Cornil, J.; Friend, R. H.; Beljonne, D. Exciton versus Electronic Couplings in Molecular Assemblies: The Importance of Non-Nearest Neighbour Interactions J. Chem. Phys. 2009, 130, 044105
67. Egelhaaf, H.-J.; Haiber, J.; Gierschner, J.; Oelkrug, D. Optical Constants of Highly Oriented Oligothiophene Films and Nanoparticles Opt. Mater. 1999, 12, 395-401
68. A detailed comparison of the IR spectrum of DSB crystallites in KBr pellets (found in: Hrenar, T.; Mitric, R.; Meic, Z.; Meier, H.; Stalmach, U. Vibrational Spectra and DFT Calculations of PPV-Oligomers J. Mol. Struct. 2003, 661-662, 33-40) with DFT-calculated spectra of the rotamers depicted in Figures S3 and S4 of the SI gives evidence mainly for the anti form and minor contributions of syn.
69. Petelenz, P.; Andrzejak, M. Vibronic Interpretation of the Low-Energy Absorption Spectrum of the Sexithiophene Single Crystal J. Chem. Phys. Lett. 2000, 113, 11306-11314
70. Mie, G. Beiträge zur Optik Trüber Medien, Speziell Kolloidaler Metallösungen Ann. Phys. 1908, 25, 377-445
71. Meskers, S. C. J.; Janssen, R. A. J.; Haverkort, J. E. M.; Wolter, J. H. Relaxation of Photo-Excitations in Films of Oligo- and Poly-(para-Phenylene Vinylene) Derivatives Chem. Phys. 2000, 260, 415-439
72. Zhao, Z.; Spano, F. C. Multiple Mode Exciton-Phonon Coupling: Applications to Photoluminescence in Oligothiophene Thin Films J. Phys. Chem. C 2007, 111, 6113-6123
73. Gierschner, J.; Mack, H.-G.; Oelkrug, D.; Waldner, I.; Rau, H. Modeling of the Optical Properties of Cofacial Chromophore Pairs: Stilbenophane J. Phys. Chem. A 2004, 108, 257-263
74. Lüer, L.; Egelhaaf, H.-J.; Oelkrug, D. (Photo)Conductivity of Conjugated Oligomer Films: Mobile Charge Carrier Formation by Oxygen Opt. Mater. 1998, 9, 454-460
75. Kazzaz, A. A.; Zahlan, A. B. Exciton Diffusion in Naphthalene Crystals Phys. Rev. 1961, 124, 90-95
76. Agranovich, V. M. Excitations in Molecular Solids; Oxford University Press Inc.: New York, 2008.
77. van Hutten, P. F.; Krasnikov, V.; Brouwer, H. J.; Hadziioannou, G. Excimer Luminescence from Single Crystals and Films of a Cyano-Substituted Phenylene-Vinylene Model Compound Chem. Phys. 1999, 241, 139-154
78. Gierschner, J.; Egelhaaf, H.-J.; Mack, H.-G.; Oelkrug, D.; Martinez Alvarez, R.; Hanack, M. Luminescence of Molecules Confined in Nanochannels Synth. Met. 2003, 137, 1449-1450
79. Bazan, G. C.; Oldham, W. J., Jr.; Lachicotte, R. J.; Tretiak, S.; Chernyak, V.; Mukamel, S. Stilbenoid Dimers: Dissection of a Paracyclophane Chromophore J. Am. Chem. Soc. 1998, 120, 9188-9204
80. Conwell, E. M. Mean Free Time for Excimer Light Emission in Conjugated Polymers Phys. Rev. B 1998, 57, 14200-14202
81. Samuel, I. D. W.; Rumbles, G.; Collison, C. J.; Moratti, S. C.; Holmes, A. B. Intra- and Inter-Molecular Photoexcitations in a Cyano-Substituted Poly(p-Phenylenevinylene) Chem. Phys. 1998, 227, 75-82
82. Cerullo, G.; Lanzani, G.; De Silvestri, S.; Egelhaaf, H.-J.; Lüer, L.; Oelkrug, D. Primary Photoexcitations in Oligophenylenevinylene Thin Films Probed by Femtosecond Spectroscopy Phys. Rev. B 2000, 62, 2429-2436
83. Lüer, L.; Egelhaaf, H. -J.; Oelkrug, D.; Gadermaier, C.; Cerullo, G.; Lanzani, G. Charge Carrier Photogeneration in Oligo(phenylenevinylene) Thin Films: A Quantitative Study Phys. Rev. B 2003, 68, 155313
84. Gierschner, J. Directional Exciton Transport in Supramolecular Nanostructured Assemblies Phys. Chem. Chem. Phys. 2012, 14, 13146-13153
85. Wang, H.; Li, F.; Ravia, I.; Gao, B.; Li, Y.; Medvedev, V.; Sun, H.; Tessler, N.; Ma, Y. Cyano-Substituted Oligo(p-phenylene vinylene) Single Crystals: A Promising Laser Material Adv. Funct. Mater. 2011, 21, 3770-3777
86. Oelkrug, D.; Tompert, A.; Egelhaaf, H.-J.; Hanack, M.; Steinhuber, E.; Hohloch, M.; Meier, H.; Stalmach, U. Towards Highly Luminescent Phenylene Vinylene Films Synth. Met. 1996, 83, 231-237
87. Varghese, S.; Yoon, S.-J.; Casado, S.; Calzado, E. M.; Boj, P. G.; Díaz-García, M. A.; Resel, R.; Fischer, R.; Milián-Medina, B.; Wannemacher, R. Stimulated Resonance Raman Scattering and Lasing Oscillation in Highly Emissive Distyrylbenzene Based Molecular Crystals Adv. Mater. 2012, 24, 6473-6478
88. Yoon, S.-J.; Varghese, S.; Park, S. K.; Wannemacher, R.; Gierschner, J.; Park, S. Y. Color-Tuned, Highly Emissive Dicyanodistyrylbenzene Single Crystals: Manipulating Intermolecular Stacking Interactions for Spontaneous and Stimulated Emission Characteristics Adv. Opt. Mater. 2012, 1, 232-237
89. Rumi, M.; Ehrlich, J. E.; Heikal, A. A.; Perry, J. W.; Barlow, S.; Hu, Z.; McCord-Maughon, D.; Parker, T. C.; Röckel, H.; Thayumanavan, S. Structure-Property Relationships for Two-Photon Absorbing Chromophores: Bis-Donor Diphenylpolyene and Bis(styryl)benzene Derivatives J. Am. Chem. Soc. 2000, 122, 9500-9510
90. Gierschner, J.; Park, S. Y. Luminescent Distyrylbenzenes: Tailoring Molecular Structure and Crystalline Morphology J. Mater. Chem. C 2013, 1 10.1039/C3TC31062K