Crystalloluminescence produced during the polymorphic phase transition of growing crystallites

Abstract

The present paper reports the crystalloluminescence (CRL) produced during the polymorphic phase transition of growing crystallites and models the dynamics of the process. The CRL emission may take place during the polymorphic phase transition of crystals due to several processes such as production of micro-fracture of crystallites during the phase transition, thermal population in the over-strained sites and electronic excitation by the energy released during the phase transition. Considering the basic concepts of crystallization from the supersaturation solution, expressions are derived which are able to explain satisfactorily the temporal, thermal, spectral, concentration and other characteristics of the CRL. It is shown that the induction period for crystal nucleation, and the lifetime of supersaturation, may be determined from the CRL measurements.

Fluorescent Crystalloluminescence of N-Isopropylcarbazole

“…A solid−solid phase transition accompanied by lattice rearrangements releases energy that can excite a crystal. Indeed, As 2 O 3 crystals can take two phases; monoclinic and cubic geometries . Crystalline modification from the former to the latter accompanies the XTL.…”

“…Indeed, As 2 O 3 crystals can take two phases; monoclinic and cubic geometries. 6 Crystalline modification from the former to the latter accompanies the XTL. Theoretical modeling was developed by Chandra on the basis of a homogeneous nucleation theory and precipitation kinetics.…”

“…The interrelations between XTL and the photoluminescence (PL) of the material as well as the temporal evolution of XTL have also been investigated in detail. In addition to various experimental approaches, several groups have also reported theoretical models for the excitation mechanisms of XTL on the basis of nucleation theories. − …”

“…In addition to various experimental approaches, several groups have also reported theoretical models for the excitation mechanisms of XTL on the basis of nucleation theories. [5][6][7] On the other hand, studies on XTL in organic substances have hitherto been limited to a few systems. To the best of our knowledge, only four reports have appeared, with each being published almost a decade apart.…”

Crystallochemiluminescence of solutions

“…CrL can be induced by the microdestruc tion of crystallites during phase transition, thermal stress in overstrained lattice, and electronic excitations of free energy during phase transition [2]. Since the processes occurring in the metastable range of exist ence of supercooled (supersaturated) solutions have not been thoroughly investigated, the adequacy of a theoretical description of CrL to real processes is not discussed in this study.…”