Sol–gel-based phenolphthalein immobilized AuNPs (phph-AuNPs) of different shapes such as spherical, dendrites, and flower are observed by varying pHs 1–12. pH 1 induced the Au cages, and pH 2–6 revealed the different shapes of dendrites. Moreover, pH 7–8 assisted phph-AuNPs exhibited the spherical shape which transformed into truncated dendrites such as flowers at pH 9–11, and again spheres at pH 12. FTIR spectra exhibited the bonding vibration of AuNPs and phenols. pH 12 assisted phph-AuNPs are observed highly porous (79%) compared to pH 1 assisted phph-AuNPs (60%) porosity and low (1.1) refractive index. Furthermore, pH 1 assisted phph-AuNPs are found to possess RMS 11 nm and thickness 56 nm which increased up to 23 and 88 nm, respectively, by increasing the pH up to 12. The pKa ~9.4 of the pH 1–12 assisted phph dye is observed at 559 nm which increased up to 9.9 at 556 nm for pH 1–12 assisted phph-AuNPs, suggesting a wide range of sensitivity. Fast response time ~0.6 s is measured at pH 12 assisted phph-AuNPs. At acidic pH, higher photoluminescence (PL) intensity indicates a high charge carrier’s recombination. Experimental findings confirmed that pH has a great influence on the morphology of phph-AuNPs.

通过不同的 pH 值 1-12 观察到不同形状（如球形、树枝状和花状）的溶胶-凝胶基酚酞固定金纳米粒子（phph-AuNPs）。pH 1 诱导金笼，pH 2-6 显示不同形状的枝晶。此外，pH 7-8 辅助的 phph-AuNPs 表现出球形，在 pH 9-11 时转变为截断的树突，如花，在 pH 值 12 时再次变成球形。 FTIR 光谱显示了 AuNPs 和苯酚的键合振动。与 pH 1 辅助的 phph-AuNPs (60%) 孔隙率和低 (1.1) 折射率相比，pH 12 辅助的 phph-AuNPs 被观察到高度多孔 (79%)。此外，发现 pH 1 辅助的 phph-AuNPs 具有 11 nm 的 RMS 和 56 nm 的厚度，通过将 pH 增加到 12，分别增加到 23 和 88 nm。pKa ~ 9。在 559 nm 处观察到 4 个 pH 1-12 辅助的 phph 染料，对于 pH 1-12 辅助的 phph-AuNP，在 556 nm 处增加到 9.9，表明灵敏度范围很广。在 pH 12 辅助的 phph-AuNPs 下测量了大约 0.6 秒的快速响应时间。在酸性 pH 值下，较高的光致发光 (PL) 强度表明电荷载流子的重组率较高。实验结果证实，pH 值对 phph-AuNPs 的形态有很大影响。