Optical response and emission waveguiding in rubrene crystals

Abstract

International audienceThe optical response of rubrene crystals is described by providing the full UV-VIS dielectric tensor. Consistently with the molecular and crystal symmetries, the lowest crystal transition originates from an Au molecular transition, it is polarized along the c axis (normal to the larger crystal face), and it is the origin of the emission, which is self-guided towards the edge where the corresponding polarization and intensity angular distribution are detected. By contrast, the Bu molecular transitions give rise to Davydov states described by the other two components of the diagonal dielectric tens

Light‐Emitting Rubrene Nanowire Arrays: A Comparison with Rubrene Single Crystals

“…The directions of polarization of the M-and L-axes can be considered as c-and b-axes, respectively, in a rubrene single crystal. [30][31][32] In the LCM PL spectra obtained from the edge of both single crystals (i.e., area (1) in Fig. 4a and b), the LCM PL peak at 572 nm was stronger than that at 601 nm, as shown in Figure 4c and d. However, the LCM PL peaks from the inside (i.e., areas (2) and (3) in Fig.…”

“…We also observed the relatively long free-charge-carrier tail at a longer wavelength (!580 nm) for the rubrene nanowires. [30][31][32] The UV/ Vis absorption peaks of higher-order vibronic bands were regularly spaced, with E Ã 0-n ¼ E Ã 0-0 þ n£v C-C (i.e., 2.38, 2.55, and 2.72 eV), where n is an integer, by an energy corresponding to the C-C stretch vibration modes (£v C-C ¼ 0.17 eV). [32] The UV/ Vis absorption peaks for rubrene nanowires were similar with those of the rubrene single crystal reported earlier.…”

Study of the Hole Transport Processes in Solution‐Processed Layers of the Wide Bandgap Semiconductor Copper(I) Thiocyanate (CuSCN)

“…[26][27][28] while those for the organic semiconductors rubrene, pentacene, and poly(3-hyxylthiophene) (P3HT) are 3.3-3.9, 2.6, and 4.4, respectively. [29][30][31] The derived value of ~5 lies between the two groups and possibly reflects the weaker ionic or stronger covalent character of CuSCN due to the -SCN constituent.…”

Refractive Index Dispersion and Anisotropic Group Refractive Indices of Rubrene Crystals

“…Tavazzi et al [9,10] deduced anisotropic refractive index dispersions of rubrene along its crystal axes by fitting ellipsometry data. Their data ranged ~2.1−4.4 eV (~282−590 nm).…”