分级ZnO纳米结构在能源器件中的应用

发布时间：2018-03-14 02:24

本文选题：ZnO纳米树　切入点：有机无机杂化太阳能电池　出处：《上海大学》2015年硕士论文　论文类型：学位论文

【摘要】：Zn O是一种重要的半导体光电材料,它合成工艺简单,在可见光范围内吸收少,并具备电子传输性好、环境友好、毒性低、稳定性好、成本低等优点,在发光二极管、生物传感器、压电纳米发电机、纳米激光器、太阳能电池、光催化、光解水等领域受到了广泛的关注。本文阐述如何通过电沉积、低温水热两步法廉价、有效地制备大规模Zn O纳米树阵列结构。并将制备出的氧化锌纳米树状结构应用到聚合物太阳能电池和光电解水中,研究不同退火温度对氧化锌晶体形貌和光电解水性能的影响,以及二氧化钛和氧化镁处理的氧化锌纳米树对杂化太阳能电池效率的影响。研究内容和取得的主要结果如下:(1)通过电沉积制备初级纳米棒,采用溶胶凝胶法在纳米棒表面提拉种子层,经过煅烧后,通过水热法在纳米棒上生长分支,得到纳米树状结构。通过扫描电镜、X-射线衍射等手段研究Zn O纳米阵列的结构和性能。结果表明,溶胶陈化处理对Zn O纳米分支结构的生长具有决定性影响,陈化处理能使胶粒粒径增大,煅烧后达到成核生长所需的临界值,从而形成有效籽晶层,在水热过程中生长出分支,形成纳米树状结构。(2)对制得的氧化锌纳米树状结构进行二氧化钛处理和氧化镁处理,然后将其组装成有机无机杂化太阳能电池。对比研究了氧化锌纳米棒和纳米树结构的电池性能,发现电流密度增加17.94%,太阳能电池转换效率提高11.53%。这是因为氧化锌的分支结构增大了电子受体与电子供体的有效接触面积,缩短电子和空穴的传输距离所导致的结果。随后将氧化锌纳米树进行不同时间的Ti O2处理,制备成Zn O-Ti O2核壳结构。结果表明,处理时间为1h所得样品的电池性能最佳,短路电流密度最大为9.95 m A cm-2,经过Ti O2处理的氧化锌纳米树组成的电池的转换效率是未做处理的电池的1.17倍。(3)将制备的氧化锌纳米树状结构应用于光电解水实验,采用X-射线衍射分析、莫特肖特基测试、线性扫描伏安法,电化学阻抗分析表征Zn O纳米阵列的晶体结构和光电解水性能。研究了不同的退火温度处理对氧化锌晶型和施主浓度的影响。将未退火和不同退火温度处理的Zn O纳米树进行线性扫描伏安分析,结果表明,在模拟太阳光照射下,光电流密度随退火温度升高而增大,在300 oC时,光电流响应范围和电流密度都达到最高值。应用莫特肖特基测试中获得了Zn O样品的施主浓度,通过进一步计算得到空间电荷层厚度。在550℃的退火温度下,虽然退火导致Zn O结晶质量的提高,但空间电荷层的厚度与纳米树状结构的分支直径相当,使得空间电荷层厚度无法随电压进一步增大,进而限制了光电流的提高。相比于纳米棒电极,纳米树电极的光电解水性能大为改善,这得益于纳米树的比表面积远大于纳米棒结构的比表面积。EIS研究结果显示,经300℃退火处理的氧化锌纳米树组装的电池在传输过程中能有效的降低电子复合几率,从而提高了电子转移效率。
[Abstract]:Zn O is an important semiconductor material, its synthesis process is simple, low absorption in the visible range, and has good electronic transmission, environmentally friendly, low toxicity, good stability, low cost, in the light emitting diode, biosensor, piezoelectric nano generator, nano lasers, solar cells, light catalytic photolysis of water and other fields have been widely concerned. This paper discusses how to through the Low Temperature Hydrothermal Electrodeposition, two steps of cheap, efficient preparation of large scale Zn O nano array structure and the tree. The tree Zinc Oxide prepared nano structure applied to polymer solar cell and light water electrolysis, study the influence of different annealing temperature water properties on crystal morphology and photoelectric Zinc Oxide solutions, impact on the efficiency of hybrid solar cells and Magnesium Oxide Zinc Oxide nano titanium dioxide and processing tree. The main research results and the contents are as follows : (1) prepared by electrodeposition of primary nanorods by sol-gel method on the nanorod surface dip seed layer, after calcination, the growth of branches in nanorods by hydrothermal method were obtained by scanning electron microscopy. The tree structure, the structure and properties of X- ray diffraction of Zn means of O nanowire arrays. The results showed that the aging treatment of Zn O nano branch structure has a decisive impact on growth, the aging process can make the particle size increase after calcination reached the critical value required for nuclear growth, so as to form an effective seed layer in the hydrothermal process have branches out to form nano tree structure (2) of. Zinc Oxide and Magnesium Oxide for processing titanium dioxide nano tree structure was prepared, and then assemble them into organic inorganic hybrid solar cells. A comparative study of the performance of Zinc Oxide nanorods and nano tree structure, found that the current density increase 17.94%, improve the conversion efficiency of solar cell 11.53%. this is because the effective contact area increases the branch structure of Zinc Oxide electron acceptor and electron donor, to shorten the distance transmission electron and hole the results. Then Ti O2 different time Zinc Oxide nano tree, prepared by Zn O-Ti O2 the core-shell structure. Show that the processing time is 1h of the sample cell performance is the best, the maximum short-circuit current density of 9.95 m A cm-2, Zinc Oxide Ti O2 tree through the nano processing of the cell conversion efficiency is 1.17 times of untreated battery. (3) the application of Zinc Oxide nano preparation in tree structure photoelecirolysis water experiment using X-, X-ray diffraction analysis, Mott Schottky test, linear sweep voltammetry, electrochemical impedance analysis of crystal structure and optical characterization of Zn O nano array solution water performance. The effects of annealing temperature difference Effect of treatment on Zinc Oxide crystal type and donor concentration. The analysis of linear sweep voltammetry not annealed and annealed at different temperatures Zn O nano trees indicated under simulated sunlight irradiation, the photocurrent density increases with the annealing temperature increasing, at 300 oC, the photocurrent response range and current density reached the highest value. The donor concentration Zn O sample application of Mott Schottky test, through further calculation of space charge layer thickness. The annealing temperature of 550 DEG C, while annealing leads to the crystallization of O to improve the quality of Zn, but the space electric branch thickness and tree structure bearing layer of nano diameter, the space charge layer the thickness not with voltage further increases, thus limiting the photocurrent increased. Compared to the nanorod electrodes, photoelectric nano electrode solution tree water performance is greatly improved, thanks to the tree than the nano surface The product area is much larger than that of the nanorod structure. The results of.EIS show that the cell assembled by Zinc Oxide nano tree annealed at 300 degree temperature can effectively reduce the electron recombination probability in the transmission process, thus improving the electron transfer efficiency.

【学位授予单位】：上海大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O614.241;TM914.4

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