本文選題：量子點 + 熒光性能��； 參考：《廣西大學》2014年碩士論文

【摘要】：隨著工業(yè)的迅猛發(fā)展,能源問題日益突出,人類迫切需求一種可再生能源代替化石能源。由于太陽能電池能夠把太陽能直接轉換成光能,而且發(fā)電過程中不會造成環(huán)境污染,因而受到人們越來越多的關注。其中,敏化太陽能電池因其制備方法簡單、光電轉換效率高等優(yōu)點,成為了太陽能電池的研究的熱點和重點。目前,有機染料作為敏化劑所取得的效率最高,但因有機染料存在價格昂貴,長期穩(wěn)定性差等缺點,限制了其在敏化電池上的應用。而熒光量子點制備方法簡單廉價,具有量子限域效應及較大的消光系數(shù),且穩(wěn)定性好,因而能夠成為一種替代有機染料的光敏材料。 本論文采用巰基水相法分別合成了ZnSe和ZnSe:Mn量子點,并通過透射電子顯微鏡(TEM)、X射線粉末衍射儀(XRD)、紫外光譜儀以及熒光光譜儀等測試手段分別對所得樣品的形貌尺寸、晶體結構、吸收光譜以及發(fā)射光譜進行了表征。其次,利用水熱法制備了ZnO納米棒陣列,并以此作為電池載體材料,將之前實驗所得的ZnSe和ZnSe:Mn納米晶作為不同的光敏化劑,通過直接吸附法(DA)將兩者組裝成量子點敏化太陽能電池器件,分別討論了ZnSe沉積時間、沉積溫度和ZnSe:Mn沉積時間、沉積溫度對ZnO太陽能電池的光電性能的影響。主要研究內容及結論為： (1)以SeO2為硒源,通過一步法合成了水溶性的ZnSe量子點。探討了穩(wěn)定劑種類及用量、反應時間、Zn/Se摩爾比例、體系初始pH值對ZnSe量子點光學性質的影響。所得的巰基乙酸(TGA)包裹的ZnSe量子點具有最佳的熒光性能,最高量子產率達到了12.8%。其發(fā)光區(qū)域在藍綠光范圍內；紫外吸收峰相對于體材料發(fā)生了一定程度的藍移；量子點顆粒為近球形,尺寸大約為3-4nm,呈閃鋅礦立方晶型。 (2)以半胱氨酸(L-cys)為穩(wěn)定劑,通過一種新穎的綠色合成方法在水溶液中制備了Mn離子摻雜的ZnSe量子點。研究發(fā)現(xiàn)反應時間、Mn的摻雜量、Zn/Se摩爾比例及初始pH值對ZnSe:Mn量子點的熒光性能有很大影響。在最佳實驗條件下生成的ZnSe:Mn量子點為立方晶型,粒徑約4-5nm,紫外吸收峰強度大于未摻雜的ZnSe量子點,最大熒光量子產率達7.2%,其發(fā)光位于白光區(qū)域,CIE坐標為(x=0.34,y=0.32)。 (3)采用水熱法通過優(yōu)化制備工藝條件,制備出了形貌規(guī)則和性能最佳的ZnO納米棒陣列。再利用DA法在ZnO納米棒陣列上分別沉積ZnSe和ZnSe:Mn量子點,即得量子點敏化的ZnO太陽能電池。研究發(fā)現(xiàn)當ZnSe沉積時間和沉積溫度分別為5h和60℃時,ZnO太陽能電池的光電性能最佳,其轉化效率達到0.100%。短路電流1.392mA·cm-2,開路電壓0.391V,填充因子0.183。而當ZnSe:Mn沉積時間和沉積溫度分別為3h和60℃時,ZnO太陽能電池的光電轉化效率最高則可達到0.280%,此時光電流密度為2.245mA·cm-2,開路電壓達到0.670V,填充因子O.182。
[Abstract]:With the rapid development of industry, the problem of energy is becoming more and more serious, and mankind urgently needs a kind of renewable energy to replace fossil energy. People pay more and more attention to solar cells because they can convert solar energy directly into light energy and will not cause environmental pollution in the process of power generation. Among them, sensitized solar cells have become the focus of solar cell research because of the advantages of simple preparation method and high photoelectric conversion efficiency. At present, the efficiency of organic dyes as sensitizer is the highest, but the application of organic dyes in sensitized batteries is limited because of their high price and poor long-term stability. On the other hand, the preparation method of fluorescent quantum dots is simple and cheap, with quantum limiting effect, large extinction coefficient and good stability, so it can be used as a substitute for organic dyes Guang Min materials. In this paper, ZnSe and ZnSe:Mn quantum dots were synthesized by sulfhydryl aqueous phase method, and the morphology and crystal structure of the samples were measured by TEM, UV and fluorescence spectrometer, respectively, by means of transmission electron microscope (TEM), X-ray powder diffractometer (XRD), UV spectrometer and fluorescence spectrometer. Absorption spectra and emission spectra were characterized. Secondly, ZnO nanorod arrays were prepared by hydrothermal method and used as carrier materials for battery. ZnSe and ZnSe:Mn nanocrystals obtained from previous experiments were used as different Guang Min agents. The quantum dot-sensitized solar cell devices were assembled by direct adsorption method. The effects of ZnSe deposition time, deposition temperature, ZnSe:Mn deposition time and deposition temperature on the photovoltaic properties of ZnO solar cells were discussed. The main contents and conclusions are as follows: Using SeO2 as selenium source, water-soluble ZnSe quantum dots were synthesized by one step method. The effects of the type and amount of stabilizer, the reaction time and the molar ratio of Zn- / se, the initial pH value of the system on the optical properties of ZnSe QDs were discussed. The ZnSe quantum dots coated with thioglycolic acid have the best fluorescence properties with the highest quantum yield of 12.8g. The luminescence region is within the range of blue-green light, the UV absorption peak is blue shifted to some extent relative to the bulk material, and the quantum dot particle is nearly spherical, with a size of about 3-4 nm, showing the cubic crystal form of sphalerite. Using cysteine L-cys) as stabilizer, Mn-doped ZnSe quantum dots were prepared in aqueous solution by a novel green synthesis method. It is found that the molar ratio of Zn / se and initial pH have great influence on the fluorescence properties of ZnSe:Mn quantum dots. Under the optimum experimental conditions, the ZnSe:Mn quantum dots are cubic crystal with a diameter of about 4-5 nm. The UV absorption peak intensity is higher than that of the undoped ZnSe quantum dots, and the maximum fluorescence quantum yield is 7.2. The ZnO nanorod arrays with the best morphology and properties were prepared by hydrothermal method. Then the ZnSe and ZnSe:Mn quantum dots were deposited on the ZnO nanorods array by DA method. The ZnO solar cells sensitized by quantum dots were obtained. It is found that the photovoltaic properties of ZnSe solar cells are the best when the deposition time and deposition temperature are 5 h and 60 鈩，

本文編號：1889442