Design and fabrication of eight zone vertical dynamic gradient freeze system for organic single crystal growth

Abstract

Design and construction of the vertical dynamic gradient freeze (VDGF) system operating in the temperature range from 50 °C to 500 °C for growing organic single crystals are described. The design of VDGF system consists of furnace, control system, translation assembly, and image capturing device. Furnace has been constructed with eight zones controlled independently by a dynamic temperature control system for achieving desired thermal environment and multiple temperature gradients, which are essential for the growth of organic single crystals. The transparent furnace enables direct observation to record and monitor the solid-liquid interface and growth of crystals through charge coupled device based video camera. The system is fully computerized hence it is possible to retrieve the complete growth and furnace history. In order to investigate the functioning of the constructed VDGF system for the growth of organic single crystals, a well known organic nonlinear optical single crystal of benzimidazole was grown. The crystalline quality and the optical transmittance of the grown crystal were studied.

Low power optical limiting studies on nanocrystalline benzimidazole thin films prepared by modified liquid phase growth technique

“…27 Further, with increasing optical path length, i.e., with increasing thickness, the optical scattering losses may also increase. That might also contribute to the decrement of transmittance in the case of films deposited at 70 • C compared to the films deposited at 60 • C. For BMZ thin films with decreasing grain size the fundamental absorption edge has been red shifted, 28 indicating the possibility of electronic transition at lower energy region. Figures 7 and 8 show the open and closed aperture Z-scan curves of the deposited BMZ thin films, respectively.…”