碳点修饰DSSCs二氧化钛光阳极的研究
发布时间：2019-06-28 20:00
【摘要】：染料敏化太阳能电池(DSSCs)以制作简单、效率相对较高、清洁无污染等优点,一直是科学工作者们研究的热点。传统染料敏化太阳能电池中染料对太阳光的利用率依然较低,球形纳米晶TiO2只能吸收小于387 nm的紫外光,电子传递效果也有限,从而限制了电池光电转换效率的提高。碳量子点(简称碳点)作为碳材料大家庭的新成员,因其具有毒性低,粒径小,荧光性能优异和电子媒介等优点逐渐引起研究者们的关注。因此,将碳点和形貌改性的TiO2修饰染料敏化太阳能电池,不仅引领我们朝绿色可持续发展迈向新的一步,也能够解决DSSCs光电效率低的问题。基于以上阐述,本论文主要做了以下工作:采用顺丁烯二酸酐和苯二胺(包括邻、间、对苯二胺)为原料,利用溶剂热法制备具有良好荧光性能的RGB碳点。在反应时间分别为4、12、20 h制备9种RGB碳点。通过IR、XPS、TEM等测试手段分析了反应4 h制得的RGB碳点(命名为邻-4,间-4,对-4碳点)表面官能团、结构及粒径等性质。通过UV-vis及PL等研究9种RGB碳点的光学性能,并计算荧光量子产率,最高达31.8%(反应条件为间苯二胺0.216 g,顺丁烯二酸酐0.216 g,乙醇12 mL,反应温度200℃,反应时间4 h)。通过荧光强度和发光范围随浓度变化研究碳点的荧光稳定性,碳点浓度从10-5 g/L至1 g/L时,荧光强度先增大后降低,浓度为10-3 g/L时强度最大,碳点浓度低时,只显示蓝色荧光,浓度高时显示红色荧光。将邻-4,间-4,对-4碳点修饰DSSCs光阳极,通过I-V曲线研究不同碳点对电池光电性能的影响,发现间-4碳点修饰后电池效率提高最明显,从6.87%提高至7.20%,短路电流从15.09 mA/cm2提高至16.10 mA/cm2。为了增强DSSCs的光谱响应,将可以吸收蓝紫光发射出蓝绿光的碳点引入其中。通过TEM、XPS及PL等研究了乙醇溶性蓝绿光碳点的形貌、结构及光学性能。修饰DSSCs光阳极,通过IPCE、EIS、I-V曲线等光电化学方法研究碳点对电池的光吸收和电池内部载流子转移行为(传输和复合)的影响,分析电池光电转换效率提高的原因。实验表明,蓝绿光碳点的粒径3-5.5 nm,属于氮氧化石墨结构,表面有大量含氮含氧官能团,具有良好的荧光性能。蓝绿光碳点修饰后电池既在光学方面通过光转换提高N719对太阳光的利用率,又在电学方面缩短电子传输路径,使得电池光电流密度明显增大(16.12 mA/cm2升至21.26 mA/cm2),电池的光电转换效率从7.25%提高至8.70%。采用溶剂热法制备了管状、棒状及花状TiO2粉体,并与P25构筑了双层结构,通过SEM,粉末XRD等,研究它们的形貌、晶相、粒径等特征。通过UV-vis,漫反射,I-V曲线等测试手段研究它们的光电性能。通过EIS,OCVD等电化学手段研究花状TiO2纳米粒子与蓝绿光碳点共同修饰电池的载流子转移行为、电子寿命等性能。结果表明,花状TiO2粒子为金红石相,在434-800 nm之间有较强的漫反射作用;花状TiO2作为光散层与P25构成双层结构光阳极,具有光散作用和增强电子传递和抑制复合作用,电池的短路电流和开路电压分别达到16.7 mA/cm2,0.751 V,光电转换效率从7.08%提高至7.69%;花状TiO2纳米粒子与蓝绿光碳点共同修饰DSSCs光阳极,结合了蓝绿光碳点的光转换作用和花状TiO2的光散及电子转移作用,最终使得电池的光电转换效率由7.08%提高至8.11%,提高了14.5%,短路电流由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，
本文编号：2507572
[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，
本文编号：2507572
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