Crystals of Linear Oligophenyls: Surface Properties, Nucleation and Growth

Crystals of linear oligophenyls p-nP (n is the number of phenyl groups) are of interest for organic electronics and photonics as effective blue emitters and scintillators. The surface properties and external conditions of the growth medium are the determining factors in the nucleation and formation of crystals. However, the crystallization processes of conjugated linear molecules are still understudied and there is practically no experimental data on the surface properties of solutions and crystals. At the same time, there are few studies in the literature on modeling the surface energy of the crystal faces of these substances [1]. This work presents the results of studying of the linear oligophenyls (n = 2..6) crystals growth from solutions and the vapor phase. In the approximation of the OPLS atomic force field method, the values of the surface energy of the (100), (010), (110), and (001) faces of the crystals are determined. Based on the data on the crystal structure and the obtained values of the surface energy of the faces, the morphology of the crystals is analyzed and their equilibrium shapes are predicted. Within the framework of the classical nucleation theory, the parameters of crystal nucleation under experimental conditions of growth from solutions and physical vapor transport are studied. References 1. Nabok D., Puschnig P. and Ambrosch-Draxl C. Phys. Rev. B 2008, B 77, 245316. Studies in part on crystals growth from solution and modeling the surface energy of crystal faces were made with financial support from the Ministry of Science and Higher Education of the Russian Federation within the State assignment FSRC “Crystallography and Photonics” RAS using the equipment of Collaborative Access Center “Structural diagnostics of materials” (project # RFMEF162119X0035); studies in part on crystals growth by the PVT method, their crystal structure and nucleation thermodynamic analysis were made under the support of the Russian Foundation for Basic Research (grant no. 19-32-90145); development of the approaches to purification of the conjugated oligomers was supported by the Russian Science Foundation (grant no. 18-73-10182).