铜基多元硫族化合物纳米晶的结构设计、可控合成及性能研究

发布时间：2018-05-15 17:20

本文选题：铜基硫族纳米晶 + 多形体　；参考：《中国科学技术大学》2017年博士论文

【摘要】：半导体纳米晶因其量子效应带来的独特物理化学性质,从而受到研究者的广泛关注。在过去的几十年间,半导体纳米材料的制备和应用研究均取得了飞速的发展。然而,在实际应用中,传统半导体纳米材料因无法满足低成本、易制备及无毒等的要求而受到颇了多限制。铜基多元硫族化合物纳米晶是一种具有制备方法简单、组成元素丰富且拥有高的光吸收系数等特性的新型半导体纳米材料。此类材料独特的元素组成和结构,促使其拥有一些新颖的物理和化学性质。如何设计合理的合成方法制备新型的铜基硫族化合物纳米晶,并且精确的控制其物相结构、组分和形貌及实现宏量制备,仍是目前亟待解决的关键问题。本论文旨在开展铜基多元硫族化合物纳米晶的结构设计、可控合成及性能研究。利用胶体合成法制备了一系列由纤锌矿和闪锌矿物相构成的铜基多元硫族化合物同素异相体(多形体)纳米晶,并研究了同素异相界面对光电化学性质的影响。在此基础上,利用表面活性剂和反应前驱物的协同作用,合成出铜基四元硫化物纳米带,并且实现了铜基多元硫族化合物纳米晶的宏量制备。取得的主要成果如下:1.发展了一种合金多形体纳米晶的合成方法。以二苯基硒醚为硒源,十二硫醇为硫源,通过胶体合成法制备出了不同S/Se比的铜基三元I-III-VI2多形体纳米晶。所制备的多形体具有纤锌矿圆柱和闪锌矿/黄铜矿尖端的形貌特征,且不随S/Se比例而改变。通过反应时间相关实验研究了 CuInS_2与CuInSe_2多形体纳米晶的生长机理。以多形体纳米晶制备的光电极表现出了稳定的光电化学活性。密度泛函理论计算阐明了这种多形体纳米晶的电子结构和能带匹配形式,证明这种三元多形体具有Type-II构型和优异的光生电子-空穴分离能力。2.设计并发展了一种铜基四元硫族化合物多形体纳米晶的普适合成方法。以二苯基硒醚为硒源、十二硫醇(DDT)为硫源和表面活性剂成功制备了Cu_2CdSn(S_xSe_(1-x))_4(CCTSSe)多形体,其中闪锌矿结构选择性生长在纤锌矿结构(000±2)面上。这种CCTSe多形体主要有两种形貌:子弹状(闪锌矿物相只在纤锌矿物相一端生长)和橄榄球状(闪锌矿物相在纤锌矿物相两端生长)。研究发现,产物中Cd含量直接影响多形体的形貌,且产物中子弹状CCTSSe多形体纳米晶的比例随着产物中Cd的含量的增加而增加。以DDT为硫源,成功制备了一系列Cu_2MSnS_4(M=Zn,Cd,Co,Mn,Fe)多形体纳米晶,并研究了硫醇的种类和用量、锌源的用量、溶剂种类和反应温度对多形体合成的影响。与普通的纤锌矿和闪锌矿结构CZTS纳米晶相比,多形体纳米晶表现出更优异的光催化产氢性能且橄榄球状多形体的光催化产氢效率更高,进一步证明了多形体界面的存在能够有效促进光生电子和空穴的分离。3.发展了一种铜基四元硫化物二维纳米材料的可控合成方法。通过油胺和十二硫醇的协同作用,制备了厚度仅10纳米左右的纤锌矿结构的Cu-Zn-M-S(M = In,Ga)单晶纳米带。研究发现,纳米带中锌的含量对其光催化性质有显著的影响,当ZnS/CuInS_2=4倍时,纳米带的光催化产氢速率最高且达到67μmol h.1(30mg);在相同的锌含量下,Cu-Zn-Ga-S纳米带的产氢速率可以达到80μmolh-1(30mg)。4.设计并发展了一种铜基多元硫族化合物纳米晶的宏量制备方法。铜基硫族化合物纳米晶是一种重要的能量转化材料,因此实现宏量制备可以使其更好地应用到生活与工业当中。以SeO_2为硒源、S粉为硫源,利用热注射法成功实现了单分散Cu_2Sn(S_xSe_(1-x))_3纳米晶宏量制备,并研究纳米晶中S/Se比例对合金热电性质的影响。研究发现,当S/Se比例为1/1时,Cu_2Sn(S_xSe_(1-x))_3纳米晶具有最好的热电性能且热电优值达到0.42(380℃)。此外,以二苯基硒醚为硒源、十二硫醇为表面活性剂,利用热注射法实现了单分散纤锌矿结构Cu_2ZnSnSe_4和Cu_2CdSnSe_4纳米晶的宏量制备。
[Abstract]:Because of its unique physical and chemical properties caused by its quantum effect, semiconductor nanocrystals have attracted wide attention from researchers. In the past few decades, the preparation and application of semiconductor nanomaterials have been developed rapidly. However, in practical applications, traditional semiconductor nanomaterials can not meet the low cost, and are easy to prepare and do not. Copper based polysulfide nanocrystals are a new type of semiconductor nanomaterials with simple preparation methods, rich composition and high optical absorption coefficient. The unique element composition and structure of such materials make them have some novel physical and chemical properties. The preparation of a new type of copper based sulfur compound nanocrystals by a reasonable synthesis method, and the precise control of its phase structure, composition and morphology and the realization of the macro preparation are still the key problems to be solved. This paper aims to develop the structure design, controllable synthesis and Performance Research of the copper based multicomponent sulfur compound nanocrystals. A series of copper based multielement sulfur compounds (multiform) nanocrystals were prepared by body synthesis, and the effect of the same phase boundary on the photochemical properties was studied. On this basis, a copper based four element sulfide Nana was synthesized by the synergism of surface active agents and reaction precursors. The main achievements are as follows: 1. the synthesis method of a kind of alloy multiform nanocrystalline is developed. Using two phenyl selenide as the selenium source and twelve thiol as the sulfur source, the copper based three yuan I-III-VI2 multiform nanocrystals with different S/Se ratio have been prepared by the colloidal synthesis method. The prepared polyforms have the morphology of the zinite column and the sphalerite / chalcopyrite tip, and do not change with the S/Se ratio. The growth mechanism of the CuInS_2 and CuInSe_2 nanocrystals is studied by the reaction time correlation experiment. The photoelectrochemical activity of the photoelectrode prepared by the nanocrystalline polycrystalline is stable. The theoretical calculation illustrates the electronic structure and band matching form of this polycrystalline nanocrystalline. It is proved that the three element polybody with Type-II configuration and excellent photoelectron hole separation ability.2. design and develop a universal synthesis method of copper based four element sulphur compound nanocrystals. Two phenyl selenide is the source of selenium, twelve Cu_2CdSn (S_xSe_ (1-x)) _4 (CCTSSe) polybody has been successfully prepared by thiol (DDT) as a sulfur source and surfactant. The zinc blende structure is selectively grown on the structure of wurtzite (000 + 2). This CCTSe polybody has two main morphologies: the bullets (the zinc mineral phase only grows at one end of the zinnite phase) and the rugby like (the zinc mineral phase in the mineral phase) It is found that the Cd content in the product directly affects the morphology of the polybody, and the ratio of the neutron elastic CCTSSe polycrystalline nanocrystals increases with the increase of the content of the Cd in the product. A series of Cu_2MSnS_4 (M=Zn, Cd, Co, Mn, Fe) nanocrystals have been successfully prepared by DDT as the sulfur source. The effect of variety and dosage, the amount of zinc source, the type of solvent and reaction temperature on the synthesis of polyforms. Compared with the common zinite and sphalerite CZTS nanocrystals, the polycrystalline nanocrystals exhibit better photocatalytic hydrogen production performance and the photocatalytic hydrogen production efficiency of the rugby shaped polyforms is higher, which further proves the interface of the multi form. The existence of a separation.3. which can effectively promote the photogenerated electrons and holes has developed a controlled synthesis of a copper based four element sulfide two-dimensional nanomaterial. Through the synergism of oleamine and twelve thiol, the Cu-Zn-M-S (M = In, Ga) single crystal nanoribbons with a thickness of only about 10 nanometers are prepared. The amount has a significant effect on its photocatalytic properties. When ZnS/CuInS_2=4 times, the photocatalytic hydrogen production rate of nanoribbon is the highest and reaches 67 mol h.1 (30mg). Under the same zinc content, the hydrogen production rate of Cu-Zn-Ga-S nanoribbons can reach 80 molh-1 (30mg).4. and a kind of macromolecular preparation of copper based multielement sulfur compound nanocrystals is developed. Methods. The nanocrystalline of copper based sulfur compounds is an important energy conversion material. Therefore, the implementation of macro quantity preparation can make it better applied to life and industry. Using SeO_2 as the source of selenium and S powder as the sulfur source, the preparation of the monocrystalline Cu_2Sn (S_xSe_ (1-x)) _3 nanocrystals has been successfully prepared by the thermal injection method, and the S/Se ratio in the nanocrystalline is studied. It was found that when the ratio of S/Se was 1/1, the Cu_2Sn (S_xSe_ (1-x)) _3 nanocrystals had the best thermoelectric properties and the thermoelectricity value reached 0.42 (380 degrees C). In addition, the monodisperse zinite structure Cu_2ZnSnSe_4 and Cu_2CdSnS were realized by using two phenyl selenide as the selenium source and twelve thiol as the surface active agent. The macro preparation of e_4 nanocrystalline.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB383.1

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