Wang Yujun, Chai Jing, Jiao Jinmiao, Kong Xianghao, Zhang Tinghui, Ye Ning, Hu Zhanggui, Wu Yicheng, Li Conggang
Tianjin Key Laboratory of Functional Crystal Materials, Institute of Functional Crystal, Tianjin University of Technology, Tianjin 300384, China.
State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, China.
Inorg Chem. 2024 Oct 14;63(41):19482-19488. doi: 10.1021/acs.inorgchem.4c03610. Epub 2024 Sep 30.
Mid-infrared (IR) nonlinear optical (NLO) materials have generated extensive research interest because of their crucial role in laser technology applications. Here, we report the synthesis of a novel cadmium germanate NLO crystal, KCdGeO, using spontaneous crystallization. KCdGeO demonstrates a distinct three-dimensional structural framework characterized by twisted [GeO] and [CdO] clusters, composed of [GeO], [CdO], [CdO], and [CdO] basic building units, respectively, which represents an unprecedented structural feature. The title compound undergoes a desirable congruent melting behavior at about 727 °C. Notably, KCdGeO demonstrates a short UV cutoff edge at 261 nm, coupled with a wide energy gap of 4.4 eV, and maintains an extended IR transparency window at around 6.0 μm. More importantly, it demonstrates a strong second-harmonic generation activity comparable to that of KHPO (KDP) at 1064 nm. Theoretical analyses further elucidate that the remarkable optical performances of KCdGeO are predominantly attributed to the cooperative effects of Ge-O and Cd-O bond-based motifs. These desired characteristics underscore the potential of KCdGeO as a good candidate material for mid-IR NLO applications.
