Silicon Nanochemistry

硅纳米化学

• 批准号: RGPIN-2014-04600
• 负责人: Ozin, Geoffrey
• 金额: $ 7.29万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=632704
• 关键词: Silicon; Nanochemistry

The focus of the research centers on new classes of silicon nanocrystals. The inspiration stems from our newfound ability to separate ensembles of poly-dispersed silicon nanocrystals into mono-dispersed fractions in the range of 1-5 nm, which has enabled the first recorded measurement and evaluation of the size-dependent chemical, physical and biological properties of silicon nanocrystals. Our proposed future research will expand and enrich upon these significant advances through four main themes. The first focuses on the synthesis of a novel class of silicon nanocrystals with redox active functional groups chemically tethered to the nanocrystal surface. This will enable the surface charge and hence electrical and optical properties of the silicon nanocrystals to be fine-tuned by chemical and/or electrochemical means. The archetype ncSi:R will be comprised of a redox active functional group R covalently attached to the surface of a hydride-terminated nanocrystalline silicon precursor ncSi:H via hydrosilation with an alkene or alkyne. Through chemical or electrochemical control of the number and extent of oxidation (p,q) of the capping R groups on the surface of the ncSi core the capped silicon nanocrystals can be transformed to ncSi:(1-p)R.pRq, where R will be chosen from metallocenes Cp2M, M = V, Cr, Mn, Fe, Co, Ni, coordination compounds RuBipy, aromatics Ar and fullerenes C60. The primary goal of this project is to demonstrate redox tuning of the electrical and optical properties of silicon nanocrystals. The second focuses on the synthesis of ‘naked’ silicon nanocrystals, devoid of surface organics, with controlled surface charge and colloid-stability, which will provide unparalleled access to the chemical and physical properties of the silicon core unimpeded by surface organics. In this project the archetypes [ncSi+]]X-] will be synthesized from the hydride or chloride capped precursors ncSi:H or ncSi:Cl using reagents, such as HBF4.Et2O, BH3.THF and AgPF6 to form charge-stabilized [ncSi+][BF4-], [ncSi+][BH4-] and [ncSi+][PF6-], respectively. The third focuses on the synthesis and characterization of doped forms of nanosilicon using radio-frequency plasma excitation of SiH4-PH3 and SiH4-B2H6 gaseous mixtures as well as HF/H2O/FeCl3 etching of n- and p-doped Si wafers, the goal of the project being determination of the dopant concentration and spatial location of B and P dopants in the ncSi, measurement of charge transport, optical and optoelectronic properties of n- and p-doped ncSi films as well as films with ncSi p-n junctions, potentially enabling new generation ncSi devices. The fourth is founded upon the envisioned utility of colloidally-stable nanocrystal ‘silicon inks’ for the fabrication of printable multicolor optoelectronic devices. The objective is to learn how to tailor the sizes and surfaces of silicon nanocrystals to control their solubility in polar and non-polar solvents, enhance their electrical charge transport properties, fine-tune their wavelength, and maximize their photoluminescence and electroluminescence efficiency across the visible spectral range, to optimize the stability and performance of multicolor silicon light emitting diodes, SiLEDs.

研究的重点集中在新类别的硅纳米晶体上。灵感源于我们新发现的将多分散硅纳米晶体的集合体分离成1-5 nm范围内的单分散部分的能力，这使得首次记录测量和评估硅纳米晶体的尺寸依赖性化学，物理和生物特性成为可能。我们提出的未来研究将通过四个主题扩展和丰富这些重大进展。第一个重点是合成一类新型的硅纳米晶体与氧化还原活性官能团化学拴系到硅表面。这将使得能够通过化学和/或电化学手段微调硅纳米晶体的表面电荷以及因此微调硅纳米晶体的电学和光学性质。原型ncSi：R将由氧化还原活性官能团R组成，所述氧化还原活性官能团R通过与烯烃或炔烃的硅氢化作用共价连接到双端纳米晶硅前体ncSi：H的表面。通过化学或电化学控制ncSi核表面上的封端R基团的氧化的数量和程度（p，q），封端的硅纳米晶体可以转化为ncSi：（1-p）R·pRq，其中R将选自二烯烃Cp 2 M，M = V、Cr、Mn、Fe、Co、Ni、配位化合物RuBipy、芳族化合物Ar和富勒烯C60。该项目的主要目标是展示硅纳米晶体的电学和光学性质的氧化还原调谐。第二个重点是“裸”硅纳米晶体的合成，没有表面有机物，具有受控的表面电荷和胶体稳定性，这将提供无与伦比的访问硅芯的化学和物理性质不受表面有机物的阻碍。在本项目中，原型[ncSi+]]X-]将由氢化物或氯化物封端的前体ncSi：H或ncSi：Cl使用试剂（例如，HBF_4.Et_2O、BH_3.THF和AgPF_6）分别合成电荷稳定的[ncSi+][BF_4-]、[ncSi+][BH_4-]和[ncSi+][PF_6-]。第三个重点是使用SiH 4-PH 3和SiH 4-B2 H6气体混合物的射频等离子体激发以及n和p掺杂Si晶片的HF/H2O/FeCl 3蚀刻来合成和表征掺杂形式的纳米硅，该项目的目标是确定ncSi中B和P掺杂剂的掺杂剂浓度和空间位置，测量电荷传输，光学和光电性能的n和p掺杂的ncSi薄膜以及薄膜与ncSi p-n结，潜在地使新一代ncSi器件。第四个是建立在设想的胶体稳定的“硅油墨”用于制造可印刷的光电子器件的实用性。目的是了解如何定制硅纳米晶体的尺寸和表面，以控制其在极性和非极性溶剂中的溶解度，增强其电荷传输特性，微调其波长，并在可见光谱范围内最大限度地提高其光致发光和电致发光效率，以优化单晶硅发光二极管（SiLED）的稳定性和性能。