Design and development of transparent vertical Bridgman system and growth of high quality 4-Chloro-3-Nitrobenzophenone single crystal for nonlinear optical applications

The development and examination of nonlinear optical (NLO) single crystals have garnered considerable attention owing to their prospective uses in optoelectronics and photonics. This study successfully grew 4-Chloro-3-nitrobenzophenone (4C3N) single crystals using an indigenously developed Vertical Bridgman method for nonlinear optical applications. This technique guarantees superior crystal quality, consistency, and a substantial defect-free volume, which is critical for optical applications. Notably, we have grown high-quality, bulk-sized crystals with significantly higher transmittance compared to previously reported data. The structural, optical, and thermal characteristics of the 4C3N crystals were analysed using X-ray diffraction (XRD), UV–Vis spectroscopy, and thermogravimetric analysis. UV–visible-NIR spectroscopy revealed a transmittance exceeding 83 % in the visible region, with a cut-off wavelength at 418 nm corresponding to an optical band gap energy of about 2.9 eV. Photoluminescence analysis was performed to evaluate the emission properties of the grown crystal, showing a prominent peak at 585 nm. The thermal stability of the 4C3N crystal was examined using TGA-DTA analysis, which determined its melting temperature to be 113 °C. Photocurrent measurements indicated strong photoconductive properties. Additionally, the Z-scan technique was used to measure third-order nonlinear optical properties, giving a value of 1.389 × 10^–9 esu. Thus, the grown 4C3N crystal shows significant potential for nonlinear optical applications.