Na2CdGe2Q6(Q = S, Se): two metal-mixed chalcogenides with phase-matching abilities and large second-harmonic generation responses.
In view of their inherent defects for commercial infrared nonlinear optical (IR NLO) materials, exploration for new IR NLO materials with excellent performance is an imperative and meaningful work. Herein, we report the successful design and synthesis of two metal-mixed chalcogenides containing divalent cations with d10electronic configuration: Na2CdGe2S6and Na2CdGe2Se6. Both of them crystallize in the polar Cc space group and exhibit three-dimensional tunnel structures constructed by the CdQ4tetrahedra and∞[GeQ3]nchains with Na+located in the tunnels. Furthermore, an interesting space group transformation between the monoclinic (Cc) and tetragonal (I4/mcm) systems from Na2CdGe2Se6to Na2ZnGe2Se6was discovered, which may arise from the different connection types of their building blocks (more flexible corner-sharing type in Cc while tightly edge-sharing type in I4/mcm). Remarkably, they exhibit type-I phase-matching abilities and large second harmonic generation (SHG) responses (0.8 and 2 times that of benchmark AgGaS2at 2.09 μm fundamental light). Notably, Na2CdGe2S6satisfies the essential requirements (coexistence of large NLO response and high laser damage threshold) as one excellent IR NLO material. The structure-property relationship has also been investigated through theoretical calculations and the results indicate that the origin of their NLO effects can be attributed to CdQ4and GeQ4units.
Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011, China. wukui@ms.xjb.ac.cn slpan@ms.xjb.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
Guang-Mao
GM
Li
Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011, China. wukui@ms.xjb.ac.cn slpan@ms.xjb.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
Qiong
Q
Liu
Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011, China. wukui@ms.xjb.ac.cn slpan@ms.xjb.ac.cn.
Kui
http://orcid.org/0000-0003-4521-4507
K
Wu
Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011, China. wukui@ms.xjb.ac.cn slpan@ms.xjb.ac.cn.
Zhi-Hua
http://orcid.org/0000-0001-8726-7952
ZH
Yang
Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011, China. wukui@ms.xjb.ac.cn slpan@ms.xjb.ac.cn.
Shi-Lie
http://orcid.org/0000-0003-4521-4507
SL
Pan