Thorough investigation on the high-temperature polymorphism of dipentyl-perylenediimide: thermal expansion vs. polymorphic transition

Abstract

N,N’-dipentyl-3,4,9,10-perylendiimide (PDI-C5) is an organic semiconducting material which has been extensively investigated as model compound for its optoelectronic properties. It is known to be highly thermally stable, that it exhibits...

Theoretical study of the tuning role of β-methylthio or β-methylselenyl on the charge-transport properties of acenedithiophenes derivatives

“…37 This was mainly considered due to the inability of B3LYP to describe the dispersion attractive part of the van der Waals interaction, and as PW91 has some advantage in this respect. This has also been verified by many researchers; wherein Huang and Kertesz proved that the conclusions drawn by the PW91 functional on dealing with the calculation of transfer integrals will be closer to the experimental value, 38,39 as also recognized by Bredas, 40 Zhong-min Su, 41–43 Frank Würthner, 44 Yves Rubin, 45 and others 46–53 and as widely used in recent years.…”

Molecular Design and Crystal Chemistry of Polyfluorinated Naphthalene‐bis‐phenylhydrazimides with Superior Thermal and Polymorphic Stability and High Solution Processability

“…[8,14,15,16] Remarkably, many cases of derivatives with different alkyl substituents well-documented the differences of the electron mobility as the consequence of the optimized intermolecular interactions, or, in other words, of more suitable interplanar distances (and offsets) between π-π stacked parallel cores in the solid state. In contrast, the effect of branching bulky or flexible residues on the propensity to polymorphs formation [17,18,19,20] and on thermal stability remains a rather overlooked aspect in NDI/PDI studies, if compared to other essential properties, such as good electrical conductivity and low thermal conductivity. The interest in this regard is indeed rapidly raising since thermal stability and polymorphic versatility are known to be detrimental to devices function and are essential requirements for organic photovoltaics and thermoelectrics (OTEs).…”

Optical and electronic properties of different thin-film polymorphs of PDIF-CN2 controlled by zone-casting conditions

“…Annealing-induced rearrangement can occur in meta-stable polymorphs of PDIs. 12 Consequently, the thermal stability of the zone-cast PDIF-CN 2 polymorphs was investigated. However, no phase transformation could be observed for either polymorph even after thermal annealing for 1 hour at 170 °C (see Fig.…”

“…9 The crystal structures of small molecule OSCs can be influenced by the deposition or growth methods (e.g., physical vapour transport (PVT), thermal evaporation, or solutionprocessing) and their precise conditions, as well as postdeposition treatment. 10,11 The obtained polymorphs are typically characterized and distinguished by single-crystal X-ray structure analysis 12,13 or grazing incident wide-angle X-ray scattering (GIWAXS) for thin films, 3,14 low-frequency Raman spectroscopy, 15,16 and even fluorescence spectroscopy and microscopy. 17 For example, the optical properties within the large perylene diimide (PDI) family depend strongly on the molecular packing and many PDI derivatives show pronounced polymorphism.…”

“…17 For example, the optical properties within the large perylene diimide (PDI) family depend strongly on the molecular packing and many PDI derivatives show pronounced polymorphism. 12,[18][19][20] They generally adopt variations of either a slipped-stack packing or a twisted ''sandwich'' stack structure. 21,22 The former is found in the majority of thin films and mainly leads to H-aggregates with the exception of PDI derivatives with strongly distorted cores that form J-aggregates.…”