Department of Chemistry, Chonnam National Univeristy, 500-757 Gwangju, Republic of Korea.
Chem Asian J. 2013 Mar;8(3):653-64. doi: 10.1002/asia.201201099. Epub 2013 Jan 10.
The absorption and photoluminescence (PL) properties of silicon quantum dots (QDs) are greatly influenced by their size and surface chemistry. Herein, we examined the optical properties of three Si QDs with increasing σ-π conjugation length: octyl-, (trimethylsilyl)vinyl-, and 2-phenylvinyl-capped Si QDs. The PL photon energy obtained from as-prepared samples decreased by 0.1-0.3 eV, while the PL excitation (PLE) extended from 360 nm (octyl-capped Si QDs) to 400 nm (2-phenylvinyl-capped Si QDs). A vibrational PL feature was observed in all samples with an energy separation of about 0.192±0.013 eV, which was explained based on electron-phonon coupling. After soft oxidization through drying, all samples showed blue PL with maxima at approximately 410 nm. A similar high-energy peak was observed with the bare Si QD sample. The changes in the optical properties of Si QDs were mainly explained by the formation of additional states arising from the strong σ-π conjugation and QD oxidation.
硅量子点（Si QDs）的吸收和光致发光（PL）性质受其尺寸和表面化学性质的影响很大。本文研究了三种具有不同 σ-π 共轭长度的 Si QDs 的光学性质：辛基、（三甲基硅基）乙烯基和 2-苯基乙烯基封端的 Si QDs。从制备的样品中获得的 PL 光子能量降低了 0.1-0.3 eV，而 PL 激发（PLE）从 360nm（辛基封端的 Si QDs）扩展到 400nm（2-苯基乙烯基封端的 Si QDs）。所有样品中都观察到了一个振动 PL 特征，其能量分离约为 0.192±0.013 eV，可以用电子-声子耦合来解释。经过干燥的软氧化后，所有样品均显示出在大约 410nm 处具有最大值的蓝 PL。裸 Si QD 样品也观察到了类似的高能峰。Si QDs 光学性质的变化主要归因于形成了由强 σ-π 共轭和 QD 氧化引起的附加状态。
