近日，同济大学张弛团队报道了一种具有两步二次谐波开关的超宽带隙磺酸盐。2026年4月6日，《美国化学会志》发表了这项成果。

具有多态稳定性和外部刺激响应性的非线性光学（NLO）开关是用于光子学和传感应用的一类重要功能材料。然而，其实际应用一直受到窄带隙的严重阻碍，这种窄带隙限制了它们在（深）紫外光谱区域的透光性。

研究组报道了首个有机深紫外透明NLO开关[NH(CH₃)₃][CH₃SO₃]，该材料在293–428 K温度范围内，通过低响应、无响应和高响应三种状态，表现出热激活可逆的两步二次谐波产生（SHG）开关行为，且SHG对比度跨越多个数量级，极为显著。该温度激活的SHG在紫外-可见光波长范围内均有响应，在1064 nm处达到磷酸二氢钾（KH₂PO4）的2.6倍，创下了深紫外透明NLO开关的新纪录。详细的实验和机理研究表明，这种响应热刺激的可逆单晶到单晶结构转变源于[NH(CH₃)₃]⁺和[CH₃SO₃]⁻基本单元的平移和旋转，这一过程由分子间氢键的重排驱动，并伴随着高温下这些基本单元的逐步无序化。

附：英文原文

Title: An Ultra-Wide Bandgap Sulfonate with Two-Step Second-Harmonic Generation Switching

Author: Feiyuan Gong, Yiran Zhang, Guangfeng Wei, Xingxing Jiang, Chao Wu, Zheshuai Lin, Zhipeng Huang, Jinhu Yang, Mark G. Humphrey, Chi Zhang

Issue&Volume: April 6, 2026

Abstract: Nonlinear optical (NLO) switches featuring multistate stability and external-stimuli responsiveness represent an important class of functional materials for photonics and sensing applications. However, their practical application has been seriously impeded by their narrow bandgaps, which limit transmission in the (deep-)ultraviolet (UV) spectral region. Herein, we report the first organic deep-UV-transparent NLO switch [NH(CH3)3][CH3SO3], which exhibits a thermally activated reversible two-step switching of second-harmonic generation (SHG) via low-, no-, and high-response states over the temperature range 293–428 K, and with remarkable SHG contrasts that span many orders of magnitude. The temperature activated SHG is responsive in the UV–visible wavelength region, reaching 2.6 × KH2PO4 at 1064 nm, setting a new record for deep-UV-transparent NLO switches. Detailed experimental and mechanistic studies demonstrate that the reversible single-crystal-to-single-crystal structure transformation responsive to thermal stimulation arises from the translation and rotation of the [NH(CH3)3]+ and [CH3SO3] primitives driven by the rearrangement of intermolecular hydrogen bonds, and the progressive disordering of these primitives at elevated temperatures.

DOI: 10.1021/jacs.5c21123

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c21123