非线性光学(NLO)材料被广泛应用于信息存储、医疗设备和精密制造等众多领域。然而，由于严格的先决条件：非中心对称的晶体结构(NCS)、合适的截止吸收边、大的二阶非线性系数、适当的双折射(Δn)、良好的稳定性、高的激光诱导损伤阈值(LIDT)等，设计合成一种性能优良的新型NLO材料是一个巨大的挑战。半有机NLO材料由单一结构中的有机和无机部分构成，代表了NLO材料的一个有趣的子分支，这种独特类型的NLO晶体结合了有机部分的结构多样性和无机部分的高稳定性。本论文中，我们选取半有机硝酸盐为研究对象，尝试将不同的有机阳离子和NO₃^?进行结合，对半有机硝酸盐的线性、非线性和爆轰性能进行研究和分析。

(1) 为了全面深入地研究半有机类硝酸盐材料的独特性能，我们对C₆H₁₄N₂(NO₃)₃·H₃O的线性、非线性和爆轰性能进行了测试和分析。在这里，我们报告了两例半有机硝酸盐之间的有趣结构变化，从NCS C₆H₁₄N₂(NO₃)₃·H₃O到中心结构(CS) C₆H₁₄N₂(NO₃)₂。我们的单晶衍射数据证实了之前报道的C₆H₁₄N₂(NO₃)₃·H₃O结构；我们发现C₆H₁₄N₂(NO₃)₃·H₃O通过在125 °C加热5 h可以变为C₆H₁₄N₂(NO₃)₂；可以通过改变离子比例完成C₆H₁₄N₂(NO₃)₂向C₆H₁₄N₂(NO₃)₃·H₃O的转化，也就是中心向非中心对称结构的转化。此外，我们研究了DHN的NLO性质：Δn = 0.110，LIDT = 2.5 × KDP，SHG = 1.60 × KDP和相位匹配行为等，并通过理论计算揭示了NO₃^?对DHN的NLO特性的显著贡献。更有趣的是，我们发现DHN在172.3 °C时释放出大量的能量，它具有作为高能量密度材料(HEDM)的潜力。我们在此提出DHN具有与TNT相当的爆轰性能(密度(ρ) = 1.67 vs 1.65 g cm^?3；爆速(D) = 7.09 vs 6.66 km s^?1；爆压(P) = 23.3 vs 21.3 GPa)。

(2) 为了修整阳离子对C₆H₁₄N₂(NO₃)₃·H₃O的非线性光学效应和透过范围贡献的问题，结合吡啶盐类的优势，利用4-氨基吡啶和浓硝酸合成了4-氨基吡啶硝酸盐(C₅H₇N₂)NO₃，该化合物结晶于P2₁/c空间群。紫外吸收截止边为262 nm，带隙为4.73 eV。通过计算其理论带隙为3.36 eV，为间接带隙。分析其态密度分布图，可以得知NO₃^?和[C₅H₇N₂]⁺对(C₅H₇N₂)NO₃的带隙均有贡献。设计并调整(C₅H₇N₂)NO₃的结构使其呈现非中心对称结构是进一步的研究方向。

Nonlinear optics (NLO) materials are widely used in many fields such as information storage, medical devices, and precision manufacturing. However, due to strict prerequisites: non-centrosymmetric crystal structure (NCS), suitable cut-off absorption edge, big second-order nonlinear coefficient, suitable birefringence (Δn), good stability, high laser-induced damage threshold (LIDT), etc., it is a great challenge to design and synthesize a novel NLO material with excellent performance. Semi-organic NLO materials are composed of organic and inorganic moieties in a single structure and represent an interesting sub–branch of NLO materials. This unique type of NLO crystal combines the structural diversity of the organic moiety with the high stability of the inorganic moiety. In this paper, we select semi–organic nitrate as the research object, and try to combine different organic cations and nitrate to study and analyze the properties of semi–organic nitrate: linear, nonlinear and detonation.

(1) In order to comprehensively and deeply study the unique properties of semi-organic nitrate-like materials, we tested and analyzed the linear, nonlinear and detonation properties of C₆H₁₄N₂(NO₃)₃·H₃O. Here, we report an interesting structural change between two semiorganic nitrates, from NCS C₆H₁₄N₂(NO₃)₃·H₃O to centrosymmetric crystal structure (CS) C₆H₁₄N₂(NO₃)₂. Our single crystal diffraction data confirmed the previously reported structure of C₆H₁₄N₂(NO₃)₃·H₃O; we found that C₆H₁₄N₂(NO₃)₂ was transformed into C₆H₁₄N₂(NO₃)₂ by heating at 125 °C for 5 h; structurally C₆H₁₄N₂(NO₃)₂ The transformation between 2 and C₆H₁₄N₂(NO₃)₃·H₃O can be accomplished through the change of ion ratio. Moreover, the nonlinear and linear optical properties of C₆H₁₄N₂(NO₃)₃·H₃O are reported: Δn = 0.110, LIDT = 2.5 × KDP, maximum SHG = 1.60 × KDP and phase matching behavior, et al. The significant contribution of NO₃^? to the NLO properties is revealed by theoretical calculations. More interestingly, we found that DHN releases a large amount of energy at 172.3 °C, indicating its potential as a high energy density material (HEDM). We propose here that C₆H₁₄N₂(NO₃)₃·H₃O has comparable detonation performance to TNT (density (ρ) = 1.67 vs 1.65 g cm^?3; detonation velocity (D) = 7.09 vs 6.66 km s^?1; detonation pressure (P) = 23.3 vs 21.3 GPa).

(2) In order to adjust the contribution of cations to the SHG and penetration range of C₆H₁₄N₂(NO₃)₃·H₃O, combined with the advantages of pyridine salts, 4-aminopyridine nitrate was synthesized by using 4-aminopyridine and concentrated nitric acid. At present, we obtained a (C₅H₇N₂)NO₃, the salt belongs to the centrosymmetric space group P2₁/c. Its UV absorption cut-off edge is 262 nm and the band gap is 4.73 eV. The theoretical band gap is calculated to be 3.36 eV, which is an indirect band gap. By analyzing its density of states distribution map, it is calculated that both nitrate anion and [C₅H₇N₂]⁺ cation contribute to the band gap. The further research direction is to design and adjust the structure of (C₅H₇N₂)NO₃ to present an acentric symmetry structure.