【摘要】：染料敏化太陽能電池,因?yàn)榈统杀尽⒏咝�、易于制造等�?yōu)點(diǎn),具有很大的潛力成為規(guī)模化生產(chǎn)的新型太陽能電池。盡管已經(jīng)實(shí)現(xiàn)13%的光電轉(zhuǎn)換效率,從應(yīng)用角度,仍然需要進(jìn)一步提升效率。限制染料敏化太陽能電池效率提升的主要瓶頸在于,光陽極中光生電子在通過二氧化鈦顆粒的傳輸過程中,由于納米顆粒間的缺陷和弱連接,導(dǎo)致電子在傳輸過程中發(fā)生大量的復(fù)合反應(yīng),限制了電池的輸出電流。為了改善納米顆粒間的連接,提升光陽極對(duì)光生電子收集效率,從而實(shí)現(xiàn)更高的光電轉(zhuǎn)換效率。石墨烯,一種性質(zhì)穩(wěn)定的二維納米碳材料,因?yàn)榫哂懈哂诙趸仈?shù)億倍的電導(dǎo)率,被作為電荷傳輸材料引入到染料敏化太陽能電池光電陽極中。本課題主要探索綠色無毒條件下制備含有高導(dǎo)電性石墨烯并且成分均勻的石墨烯-二氧化鈦復(fù)合物,并將其制成染料敏化太陽能電池的光陽極,用于提升光陽極中電子傳輸,提高電池效率。我們提出了一個(gè)簡(jiǎn)單方法,在溫和條件下實(shí)現(xiàn)綠色環(huán)保的制備石墨烯-二氧化鈦光陽極,在常溫條件下使用維生素C作為還原劑,通過簡(jiǎn)單的攪拌和離心操作,將氧化石墨烯還原為石墨烯(RGO)從而制備成石墨烯-二氧化鈦納米復(fù)合材料。調(diào)整復(fù)合物中RGO的含量,制備成不同含量的RGO-TiO2光陽極。在具有相同薄膜厚度的情況下,0.75 wt.%RGO-TiO2復(fù)合物相比于普通二氧化鈦顆粒提升了 30.2%的光電轉(zhuǎn)換效率。RGO-TiO2復(fù)合光陽極在16μm厚度的情況時(shí),能夠得到最高的轉(zhuǎn)換效率。此外,我們還研究了石墨烯尺寸對(duì)于電池效率的影響,發(fā)現(xiàn)使用較小的石墨烯能夠改善染料吸附量,從而得到更高的轉(zhuǎn)換效率。探討了光陽極加入RGO后對(duì)電池各項(xiàng)參數(shù)的影響,更進(jìn)一步研究了電池的電學(xué)性能,發(fā)現(xiàn)效率的提升來源于石墨烯改進(jìn)了光生電子的傳輸能力,降低了復(fù)合反應(yīng)的數(shù)量,延長(zhǎng)了電子壽命。然而,還原法制備的石墨烯,因?yàn)樵谥苽溥^程中,需要先氧化成為氧化石墨烯,再還原為石墨烯,而氧化過程和還原過程會(huì)在石墨烯片層內(nèi)產(chǎn)生缺陷,導(dǎo)致石墨烯品質(zhì)下降,降低導(dǎo)電性,最終限制了電池效率。為了解決上述問題,我們利用簡(jiǎn)單的液相超聲剝離石墨,得到剝離石墨烯(EGS),然后混合TiO2納米顆粒,制備EGS-TiO2復(fù)合光陽極。由于EGSL比常規(guī)的RGO具有更少的缺陷:EGS拉曼ID/IG～0.256遠(yuǎn)小于RGO～1.128,EGS可以實(shí)現(xiàn)更高的電子遷移率從而實(shí)現(xiàn)更高的導(dǎo)電性。經(jīng)過實(shí)驗(yàn)測(cè)量EGS具有近兩倍于RGO的電導(dǎo)率,并且功函數(shù)(4.51 eV)恰好處于二氧化鈦和導(dǎo)電玻璃之間,有利于電子傳遞。EGS-TiO2光陽極實(shí)現(xiàn)了 8.24%的轉(zhuǎn)換效率,對(duì)比相同的制備條件下的RGO-TiO2光陽極提升了 19%。效率的提升來自于EGS具有較少的面內(nèi)缺陷,相比RGO或者只有TiO2的光陽極,可以具有更好的電導(dǎo)率實(shí)現(xiàn)更好的光電子傳輸。
[Abstract]:Dye-sensitized solar cells have great potential for large-scale production because of their advantages of low cost, high efficiency and easy to manufacture. Although 13% optoelectronic conversion efficiency has been achieved, there is still a need to further improve the efficiency from an application point of view. The main bottleneck limiting the efficiency improvement of dye sensitized solar cells is that the photogenerated electrons in the photoanode are due to the defects and weak connections between the nanoparticles during the transmission through the TIO _ 2 particles. A large number of complex reactions occur during the transmission of electrons, limiting the output current of the battery. In order to improve the connection between nanoparticles and improve the photoelectron collection efficiency of photoanode, thus achieving a higher photoelectric conversion efficiency. Graphene, a stable two-dimensional nano-carbon material, is introduced as a charge transfer material into the photoanode of a dye sensitized solar cell because of its conductivity hundreds of millions of times higher than titanium dioxide. In this paper, we mainly explore the preparation of graphene titanium dioxide complex containing high conductivity graphene and uniform composition under green nontoxic conditions, and make it into a dye sensitized solar cell photoanode, which is used to enhance electron transport in photoanode. Improve battery efficiency. We proposed a simple method to prepare graphene-titanium dioxide photoanode under mild conditions. Under normal temperature, vitamin C was used as reducing agent, and simple agitation and centrifugation were used to prepare graphene-titanium dioxide photoanode. Graphite-titanium dioxide nanocomposites were prepared by reducing graphene oxide to graphene (RGO). RGO-TiO2 photoanode with different content was prepared by adjusting the content of RGO in the complex. Under the condition of the same film thickness, the highest conversion efficiency can be obtained when the photoelectrochemical conversion efficiency of 0.75 wt.%RGO-TiO2 composite anode increases by 30.2% compared with that of ordinary TIO _ 2 particles. The RGO-TiO _ 2 composite photoanode has a thickness of 16 渭 m. In addition, we also studied the effect of graphene size on the efficiency of the cell. It was found that the use of smaller graphene can improve the adsorption capacity of dyes, thus obtaining a higher conversion efficiency. The effect of photoanode addition of RGO on the parameters of the battery is discussed. The electrical properties of the battery are further studied. It is found that the improvement of the efficiency comes from the improvement of the photoelectron transport ability of graphene and the reduction of the number of the composite reactions. The electron life is prolonged. However, graphene prepared by reduction process is prepared because it is first oxidized to graphene oxide and then reduced to graphene during the preparation process. However, the process of oxidation and reduction will produce defects in the graphene lamellar layer, resulting in the degradation of the quality of graphene. Reducing conductivity ultimately limits battery efficiency. In order to solve the above problems, we used simple liquid phase ultrasonic stripping graphite to obtain graphene (EGS), and then mixed TiO2 nanoparticles to prepare EGS-TiO2 composite photoanode. Because EGSL has fewer defects than conventional RGO, Raman ID/IG~0.256 is much smaller than RGO1.128EGS can achieve higher electron mobility and achieve higher conductivity. The conductivity of EGS is nearly twice that of RGO, and the work function (4.51 EV) is exactly between titanium dioxide and conductive glass, which is beneficial to the electron transfer. EGS-TiO _ 2 photoanode achieves 8.24% conversion efficiency. Compared with the same preparation conditions, the RGO-TiO2 photoanode increased by 19%. The improvement of efficiency comes from the fact that EGS has less in-plane defects. Compared with RGO or the photoanode with only TiO2, it can achieve better photoelectron transmission with better conductivity.
【學(xué)位授予單位】：鋼鐵研究總院
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TM914.4;TQ127.11

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