【摘要】：染料敏化太陽能電池(DSSCs)以制作簡單、效率相對較高、清潔無污染等優(yōu)點,一直是科學(xué)工作者們研究的熱點。傳統(tǒng)染料敏化太陽能電池中染料對太陽光的利用率依然較低,球形納米晶TiO2只能吸收小于387 nm的紫外光,電子傳遞效果也有限,從而限制了電池光電轉(zhuǎn)換效率的提高。碳量子點(簡稱碳點)作為碳材料大家庭的新成員,因其具有毒性低,粒徑小,熒光性能優(yōu)異和電子媒介等優(yōu)點逐漸引起研究者們的關(guān)注。因此,將碳點和形貌改性的TiO2修飾染料敏化太陽能電池,不僅引領(lǐng)我們朝綠色可持續(xù)發(fā)展邁向新的一步,也能夠解決DSSCs光電效率低的問題�；谝陨详U述,本論文主要做了以下工作:采用順丁烯二酸酐和苯二胺(包括鄰、間、對苯二胺)為原料,利用溶劑熱法制備具有良好熒光性能的RGB碳點。在反應(yīng)時間分別為4、12、20 h制備9種RGB碳點。通過IR、XPS、TEM等測試手段分析了反應(yīng)4 h制得的RGB碳點(命名為鄰-4,間-4,對-4碳點)表面官能團(tuán)、結(jié)構(gòu)及粒徑等性質(zhì)。通過UV-vis及PL等研究9種RGB碳點的光學(xué)性能,并計算熒光量子產(chǎn)率,最高達(dá)31.8%(反應(yīng)條件為間苯二胺0.216 g,順丁烯二酸酐0.216 g,乙醇12 mL,反應(yīng)溫度200℃,反應(yīng)時間4 h)。通過熒光強(qiáng)度和發(fā)光范圍隨濃度變化研究碳點的熒光穩(wěn)定性,碳點濃度從10-5 g/L至1 g/L時,熒光強(qiáng)度先增大后降低,濃度為10-3 g/L時強(qiáng)度最大,碳點濃度低時,只顯示藍(lán)色熒光,濃度高時顯示紅色熒光。將鄰-4,間-4,對-4碳點修飾DSSCs光陽極,通過I-V曲線研究不同碳點對電池光電性能的影響,發(fā)現(xiàn)間-4碳點修飾后電池效率提高最明顯,從6.87%提高至7.20%,短路電流從15.09 mA/cm2提高至16.10 mA/cm2。為了增強(qiáng)DSSCs的光譜響應(yīng),將可以吸收藍(lán)紫光發(fā)射出藍(lán)綠光的碳點引入其中。通過TEM、XPS及PL等研究了乙醇溶性藍(lán)綠光碳點的形貌、結(jié)構(gòu)及光學(xué)性能。修飾DSSCs光陽極,通過IPCE、EIS、I-V曲線等光電化學(xué)方法研究碳點對電池的光吸收和電池內(nèi)部載流子轉(zhuǎn)移行為(傳輸和復(fù)合)的影響,分析電池光電轉(zhuǎn)換效率提高的原因。實驗表明,藍(lán)綠光碳點的粒徑3-5.5 nm,屬于氮氧化石墨結(jié)構(gòu),表面有大量含氮含氧官能團(tuán),具有良好的熒光性能。藍(lán)綠光碳點修飾后電池既在光學(xué)方面通過光轉(zhuǎn)換提高N719對太陽光的利用率,又在電學(xué)方面縮短電子傳輸路徑,使得電池光電流密度明顯增大(16.12 mA/cm2升至21.26 mA/cm2),電池的光電轉(zhuǎn)換效率從7.25%提高至8.70%。采用溶劑熱法制備了管狀、棒狀及花狀TiO2粉體,并與P25構(gòu)筑了雙層結(jié)構(gòu),通過SEM,粉末XRD等,研究它們的形貌、晶相、粒徑等特征。通過UV-vis,漫反射,I-V曲線等測試手段研究它們的光電性能。通過EIS,OCVD等電化學(xué)手段研究花狀TiO2納米粒子與藍(lán)綠光碳點共同修飾電池的載流子轉(zhuǎn)移行為、電子壽命等性能。結(jié)果表明,花狀TiO2粒子為金紅石相,在434-800 nm之間有較強(qiáng)的漫反射作用;花狀TiO2作為光散層與P25構(gòu)成雙層結(jié)構(gòu)光陽極,具有光散作用和增強(qiáng)電子傳遞和抑制復(fù)合作用,電池的短路電流和開路電壓分別達(dá)到16.7 mA/cm2,0.751 V,光電轉(zhuǎn)換效率從7.08%提高至7.69%;花狀TiO2納米粒子與藍(lán)綠光碳點共同修飾DSSCs光陽極,結(jié)合了藍(lán)綠光碳點的光轉(zhuǎn)換作用和花狀TiO2的光散及電子轉(zhuǎn)移作用,最終使得電池的光電轉(zhuǎn)換效率由7.08%提高至8.11%,提高了14.5%,短路電流由15.7升至17.8mA/cm2,提高了13.4%。
[Abstract]:The dye-sensitized solar cell (DSSCs) has the advantages of simple production, relatively high efficiency, no pollution and the like, and has been a hot spot for scientists to study. In the traditional dye-sensitized solar cell, the utilization rate of the dye on the sunlight is still low, and the spherical nano-crystal TiO2 can only absorb the ultraviolet light of less than 387 nm, and the electron transfer effect is limited, thereby limiting the improvement of the photoelectric conversion efficiency of the battery. Carbon quantum dots (carbon dots), as a new member of the carbon material family, have gradually attracted the attention of the researchers because of its low toxicity, small particle size, excellent fluorescence performance and electronic medium. Therefore, the carbon-point and the morphology-modified TiO2-modified dye-sensitized solar cell not only leads us to a new step towards the green sustainable development, but also can solve the problem of low photoelectric efficiency of the DSSCs. Based on the above, the main work of this thesis is to prepare the RGB carbon dots with good fluorescence properties by solvothermal method using maleic anhydride and phenylenediamine (including o-, m-and p-phenylenediamine) as raw materials. Nine kinds of RGB carbon dots were prepared at the reaction time of 4,12 and 20 h, respectively. The surface functional group, structure and particle size of the RGB carbon dot (named o-4, m-4, p-4 carbon point) prepared by the reaction were analyzed by means of IR, XPS and TEM. The optical properties of 9 kinds of RGB carbon spots were studied by UV-vis and PL, and the fluorescence quantum yield was calculated. The maximum content was 31.8% (the reaction conditions were m-phenylenediamine 0.216 g, maleic acid solution 0.216 g, ethanol 12 mL, reaction temperature 200 鈩，

本文編號：2507572