A large NLO single crystal of potassium chromium sulphate (PCS) has been grown by slow evaporation solution technique. Powder X-ray diffraction (PXRD) analysis reveals that the grown crystal crystallizes in a cubic crystal system with a centrosymmetric space group of PCS single crystal. The SEM image shows the formation of block structures over the surface of the PCS crystal. The impedance study was performed for PCS crystal about the frequency at various temperatures to measure the electrical characteristics of the material. From the results, it has been observed that when the temperature rises, the bulk resistance decreases prompting an increase in the DC conductivity. Z-scan studies were used to assess the third-order nonlinear optical characteristics. The results show noticeably higher values for the nonlinear absorption coefficient (β = 7.615 × 10⁻⁶ m/W), nonlinear refractive index (− 1.6203 × 10⁻¹² m²/W), and the third-order nonlinear susceptibility (χ3 = 1.078 × 10⁻¹⁰ esu). The material exhibits self-defocusing due to its negative nonlinear refractive index, which is a key feature for optical limiting and switching applications. The excellent third-order nonlinear behaviour indicates that the PCS single crystal is appropriate for nonlinear optical applications. The intermolecular interactions of the PCS molecule were executed using the Hirshfeld surface study. PCS crystal shows good antimicrobial activity against various standard pathogens (E. coli, Staphylococcus aureus, Candida albicans).

Graphical Abstract

中文翻译：

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探索硫酸钾铬单晶的特性——一种用于光限幅和开关应用的有效三阶非线性光学材料

通过缓慢蒸发溶液技术生长了大型 NLO 单晶硫酸铬钾 (PCS)。粉末X射线衍射（PXRD）分析表明，生长的晶体结晶为具有PCS单晶中心对称空间群的立方晶系。 SEM 图像显示 PCS 晶体表面形成块状结构。对PCS晶体在不同温度下的频率进行阻抗研究，以测量材料的电特性。从结果中可以看出，当温度升高时，体电阻降低，导致直流电导率增加。 Z 扫描研究用于评估三阶非线性光学特性。结果显示非线性吸收系数 ( β  = 7.615 × 10 ^-6  m/W)、非线性折射率 (− 1.6203 × 10 ^-12 m ² /W) 和三阶非线性磁化率 (χ3 = 1.078 × 10 ^-10 esu）。该材料由于其负非线性折射率而表现出自散焦，这是光学限幅和开关应用的关键特征。优异的三阶非线性行为表明PCS单晶适合非线性光学应用。 PCS 分子的分子间相互作用是使用 Hirshfeld 表面研究进行的。 PCS晶体对各种标准病原体（大肠杆菌、金黄色葡萄球菌、白色念珠菌）表现出良好的抗菌活性。

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