本文選題：Au納米晶 + TiO2納米棒陣列　； 參考：《河南大學(xué)》2014年碩士論文

【摘要】：近幾年來，量子點(diǎn)敏化太陽能電池（QDSSCs）由于其光電轉(zhuǎn)換效率的快速提升，日益受到人們的關(guān)注。目前，Mn摻雜的CdS/CdSe共敏量子點(diǎn)敏化太陽能電池，光電轉(zhuǎn)換效率已經(jīng)達(dá)到5.4%，顯示出較好的應(yīng)用前景。另外，由于量子點(diǎn)具有激子倍增效應(yīng)（MEG），即吸收一個(gè)光子可以產(chǎn)生多個(gè)電子-空穴對(duì)，其理論光電轉(zhuǎn)換效率高達(dá)44%，有望突破Schockley-Queisser極限（31%）。 盡管在量子點(diǎn)敏化太陽能電池領(lǐng)域開展了大量的研究工作，迄今為止，其最高光電轉(zhuǎn)換效率接近6%，依然遠(yuǎn)遠(yuǎn)落后于染料敏化太陽能電池報(bào)道的最高轉(zhuǎn)換效率（~11.5%）。主要原因在于其器件結(jié)構(gòu)尚需改善、光吸收尚需進(jìn)一步增強(qiáng)、載流子復(fù)合問題尚需進(jìn)一步解決。近年來，，人們嘗試在量子點(diǎn)敏化太陽能電池中引入一維納米結(jié)構(gòu)材料，期望利用納米結(jié)構(gòu)材料獨(dú)特的光電特性提高量子點(diǎn)敏化太陽能電池的光電轉(zhuǎn)換效率。在量子點(diǎn)敏化太陽能電池中，通常采用介孔的納米顆粒薄膜作為其光陽極，分離后的光生電子在這些顆粒薄膜中采用一種“跳躍”的形式在納米顆粒之間傳輸，這種傳輸方式會(huì)造成在納米顆粒界面之間產(chǎn)生嚴(yán)重的復(fù)合，使得其光電轉(zhuǎn)換效率難以提升。而一維納米結(jié)構(gòu)材料可以為光生電子提供直接的傳輸通道，通過在量子點(diǎn)敏化太陽能電池中引入一維納米結(jié)構(gòu)材料有望大幅度提高其光電轉(zhuǎn)換效率。然而，就目前的研究現(xiàn)狀而言，基于一維（1D）納米結(jié)構(gòu)的量子點(diǎn)敏化太陽能電池的性能并沒有預(yù)期的好，主要是由于其較低的比表面積使得量子點(diǎn)的擔(dān)載量較低。因此，增強(qiáng)光吸收是提高一維納米結(jié)構(gòu)基量子敏化太陽能電池的有效途徑。 最近，貴金屬納米顆粒金、銀、銅的表面等離子體共振效應(yīng)引起了研究者的高度重視。很多研究者利用金屬納米顆粒的光散射與局域表面等離子體共振效應(yīng)（LSPR）實(shí)現(xiàn)了薄膜太陽能電池的光吸收與光電流增強(qiáng)。在第一種方式中，光照射在貴金屬納米顆粒表面直接發(fā)生散射，這種散射效應(yīng)可以有效地增加光子在太陽能電池器件中的傳播路徑，從而達(dá)到增強(qiáng)太陽能電池光吸收的目的；在第二種方式中，貴金屬納米顆粒中的電子在光子的激發(fā)作用下，產(chǎn)生集體的電磁振蕩，即等離子體共振效應(yīng)，在金屬/半導(dǎo)體肖特基接觸附近并且處于激發(fā)態(tài)的電子能夠在冷卻前越過肖特基勢壘而注入到半導(dǎo)體導(dǎo)帶中。這種等離子體共振“熱電子”注入效應(yīng)被廣泛應(yīng)用在光催化和聚合物薄膜太陽能電池中提高光催化能力和器件的光電轉(zhuǎn)換效率。但就目前的研究現(xiàn)狀而言，很少有研究者嘗試把這種等離子體共振引起的“熱電子”注入現(xiàn)象應(yīng)用于一維納米結(jié)構(gòu)材料基量子點(diǎn)敏化太陽能電池中。 為解決一維納米結(jié)構(gòu)材料基量子點(diǎn)敏化太陽能電池中由于量子點(diǎn)擔(dān)載量較低造成的光吸收較弱的問題，在本論文中，我們制備了分散性較好的金納米晶，并將其引入到一維TiO2納米棒的量子點(diǎn)敏化太陽電池中，期望能夠利用其等離子體共振效應(yīng)在一定程度上增強(qiáng)光電轉(zhuǎn)換效率。具體開展了如下三個(gè)方面的研究工作： （1）金納米晶的制備：利用檸檬酸鈉還原法，調(diào)節(jié)檸檬酸鈉的量以及反應(yīng)時(shí)間，制備了尺寸為20nm，分散性較好的球形金納米晶；采用晶種生長法，制備了長約為55nm、寬約20nm的金納米棒。 （2）金納米晶在量子點(diǎn)敏化太陽能電池中的應(yīng)用：通過水熱合成法，以FTO為基底，在180oC生長TiO2納米棒陣列，成功制備了金紅石相的TiO2納米棒陣列；通過連續(xù)離子層吸附與化學(xué)水浴法制得TiO2/CdS/CdSe/ZnS光陽極，調(diào)節(jié)連續(xù)循環(huán)反應(yīng)的次數(shù)，最后得到最優(yōu)光陽極結(jié)構(gòu)為TiO2/15CdS/20CdSe/5ZnS，光電轉(zhuǎn)換效率為1.66%；金納米顆粒注入到優(yōu)化結(jié)構(gòu)的太陽能電池中，光電轉(zhuǎn)換效率可以從1.66%增加到1.73%，提高了大約4.2%。 （3） Au/TiO2納米棒陣列復(fù)合結(jié)構(gòu)光電性能的研究：利用原位生長法，在TiO2納米棒上復(fù)合金納米顆粒；XPS研究證實(shí)Au納米顆粒與TiO2復(fù)合后有電子轉(zhuǎn)移；I-t測試結(jié)果發(fā)現(xiàn)Au/TiO2復(fù)合結(jié)構(gòu)在可見光（≥420nm）的照射下，可以產(chǎn)生明顯的光電流。該部分的研究結(jié)果表明：在可見光的激發(fā)下，Au納米顆粒的表面等離子體共振效應(yīng)產(chǎn)生的熱電子越過Au納米顆粒與TiO2導(dǎo)帶中的肖特基勢壘注入到TiO2導(dǎo)帶中，可以產(chǎn)生光電流。
[Abstract]:In recent years, quantum dot sensitized solar cell (QDSSCs) has attracted more and more attention due to its rapid increase in photoelectric conversion efficiency. At present, Mn doped CdS/CdSe co sensitive quantum dot sensitized solar cells have reached 5.4%, showing a better future. In addition, because quantum dots have exciton multiplier effect (M EG), that is, the absorption of one photon can produce multiple electron hole pairs. The theoretical photoelectric conversion efficiency is as high as 44%, which is expected to exceed the Schockley-Queisser limit (31%).
Although a lot of research work has been carried out in the field of quantum dot sensitized solar cells, up to now, the maximum photoelectric conversion efficiency is close to 6%, still far behind the highest conversion efficiency (~11.5%) reported by dye sensitized solar cells. The main reason is that the structure of the device needs to be improved, the optical absorption needs to be further enhanced and the carrier recovery is still needed. In recent years, people have tried to introduce one-dimensional nanostructured materials in quantum dot sensitized solar cells. We expect to improve the photoelectric conversion efficiency of quantum dots sensitized solar cells by using the unique photoelectric properties of nanostructured materials. In quantum dot sensitized solar cells, mesoporous nanoparticles are usually used. As the photoanode of the film, the photogenerated electrons after separation are transported between the nanoparticles in the form of "jumping" in these granular films, which will cause serious recombination between the nanoparticles and make the photoelectric conversion efficiency difficult to improve. One dimensional nanostructure material can be a photoelectron. To provide direct transmission channels, the introduction of one-dimensional nanostructured materials in quantum dot sensitized solar cells is expected to greatly improve their photoelectric conversion efficiency. However, the performance of a quantum dot sensitized solar cell based on one dimension (1D) nanostructure is not expected to be expected, mainly due to its lower performance. The specific surface area makes the loading of quantum dots low. Therefore, enhanced optical absorption is an effective way to improve one-dimensional nanostructure based quantum sensitized solar cells.
Recently, the surface plasmon resonance effect of gold, silver and copper nanoparticles in noble metal nanoparticles has attracted the attention of researchers. Many researchers use the light scattering of metal nanoparticles and the local surface plasmon resonance effect (LSPR) to realize the optical absorption and photocurrent enhancement of the thin film solar cells. In the first way, light is illuminated. The scattering of noble metal nanoparticles can effectively increase the propagation path of photons in solar cell devices, thus enhancing the absorption of solar cells. In the second ways, the electrons in the noble metal nanoparticles produce a collective electromagnetic oscillation under the excitation of the light. The plasmon resonance effect is injected into a semiconductor guide band near the metal / semiconductor Schottky contact and the electrons in the excited state across the Schottky barrier before cooling. This plasma resonance "Thermo Electron" injection effect is widely used in photocatalytic and polymer film solar cells to improve photocatalytic activity. However, as far as the current research status is concerned, few researchers have tried to apply the "hot electron" injection caused by this kind of plasma resonance to the one-dimensional nanostructured material based quantum dot sensitized solar cells.
In order to solve the problem of weak light absorption due to low quantum dots loading in one dimensional nanostructured material based quantum dot sensitized solar cells, we have prepared a better dispersive gold nanocrystal in this paper, and introduced it into the quantum dot sensitized solar cell of one dimension TiO2 nanorods, expecting to use its plasma. To some extent, the resonance effect enhances the photoelectric conversion efficiency. The following three aspects are studied concretely:
(1) preparation of gold nanocrystals: using sodium citrate reduction method to regulate the amount and reaction time of sodium citrate, the spherical gold nanocrystals with a size of 20nm and good dispersibility were prepared. The gold nanorods with a length of about 55nm and about 20nm width were prepared by the seed growth method.
(2) the application of gold nanocrystalline in quantum dot sensitized solar cells: the TiO2 nanorod array of rutile phase was successfully prepared by the hydrothermal synthesis method, FTO as the substrate and the TiO2 nanorod array in 180oC. The TiO2/ CdS/CdSe/ZnS photo anode was obtained by continuous ion layer adsorption and chemical water bath method, and the number of times of the continuous cycle reaction was adjusted. Finally, the optimal photoanode structure is TiO2/15CdS/20CdSe/5ZnS, the photoelectric conversion efficiency is 1.66%, and the photoelectric conversion efficiency can be increased from 1.66% to 1.73% in the optimized structure of the solar cells, which increases about 4.2%..
(3) study on the photoelectric properties of Au/TiO2 nanorod array composite structure: using in situ growth method to compound gold nanoparticles on TiO2 nanorods, the XPS study confirmed that the Au nanoparticles and TiO2 have electron transfer. The results of I-t test found that the Au/TiO2 composite structure can produce obvious photocurrent under the irradiation of visible light (> 420nm). Some results show that under the excitation of visible light, the thermal electrons produced by the surface plasmon resonance effect of Au nanoparticles are injected into the TiO2 conduction band of the Au nanoparticles and the Schottky barrier in the guide band of TiO2.

【學(xué)位授予單位】：河南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TM914.4;TB383.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 覃愛苗,蔣治良,鄒節(jié)明,王力生,廖雷,尹文清;用聚丙烯酰胺微波高壓合成金納米粒子[J];應(yīng)用化學(xué);2002年12期

本文編號(hào)：1819266