作为碳纳米材料家族的一员, 碳量子点(CQDs)以其独特的光电特性、环境友好、制备成本低等优点成为近年来的研究热点, 并在太阳电池、光电催化、传感器等光伏与光电领域展现出广阔的应用潜力。本文以壳聚糖为原料, 采用水热法在酸性、中性、碱性(pH=3,7,10)环境下制备了荧光碳量子点, 并对其光致发光性质和结构进行了表征。TEM测试表明, 随着pH值从3增大到10, 其粒径由2.80 nm减小到1.83 nm。将获得的碳量子点作为光敏化剂, 组装成敏化太阳电池(SSCs), 结果表明pH=3时制备出的CQDs组装的太阳电池具有最高的光电转换效率(PCE)。为了进一步提升SSCs的性能, 将CQDs与N719染料复合, 制备了共敏化太阳电池(co-SSCs)。由于CQDs的上转换特性和良好的载流子传输性能,CQDs/N719基co-SSCs的PCE较CQDs及N719染料单独敏化太阳电池显著提高, 最高PCE达9.13%。这些研究结果为制备碳量子点及组装高效敏化太阳电池提供了新思路。

Carbon quantum dots(CQDs), a member of carbon nanomaterials family, have catching growing attentions in recent years due to their distinctive photoelectric properties, environmental-friendliness and cost-effectiveness. Moreover, it shows huge potential in photovoltaic and optoelectronic applications, such as solar cells, photoelectric catalysis, sensors and so on. In herein, the CQDs were synthesized by hydrothermal method with chitosan as precursor under acid, neutral and alkaline environment(pH=3, 7, 10). At the same time, the photoluminescence properties and structures of the obtained CQDs were characterized. The TEM characterization showed that with the increase of pH value from 3 to 10, the particle size decreased from 2.80 nm to 1.83 nm. These CQDs were also used as photosensitizer to assemble into sensitized solar cells(SSCs). Resultantly, the solar cells with the CQDs obtained under pH=3 exhibited the highest photoelectric conversion efficiency(PCE). In order to further improve the performance of SSCs, N719 dye was applied to prepare co-sensitized solar cells(co-SSCs) by combing with the CQDs. Owing to up-conversion characteristics and excellent carrier transport properties of CQDs, a PCE as high as 9.13% was achieved for CQDs/N719 based co-SSCs, which is significantly higher than that of CQDs- and N719-based SSCs individually. These research results open a new door for fabricating CQDs and assembling high efficient SSCs.