三维石墨烯导电网络制备与宽光谱太阳电池探索

Photovoltaic technology is one of key technologies in the future energy constructure. New concept solar cells can meet the high standards of PV demands if the efficient solar absorption and charge transfer are achieved in PV devices. In this project, three dimensional graphene network is proposed to be constructed as the conductive backbone of the photovoltaic devices. The semiconductors, such as TiO2, quantum dots, etc., are loaded on the graphene network, and the different light absorbers have a distribution to absorb the different light to assemble wide spectrun solar cells. This research project relies on the low-temperature PECVD growth of graphene. The plasma composition, preparation condition, and nealeaction and grain growth will be studied in details in order to develop a new preparation method. Novel smart substrate design is based on the different carbon solubilities and diffusion rates for the individual metals and alloys. Dual metal or metal/insulator substrates are expected to be developed to grow graphene at very low temperature. Three dimensional graphere networks with the different porous structures are prepared by the above PECVD and smart substrate method. The new structure of solar cells based on three dimensional graphene network consists of more than one light absorbers (quantum dots, etc.) to meet the goal of wide-spectrum solar cells.

光伏发电是未来能源结构的重要组成，探索新概念太阳电池尤为重要。围绕太阳光充分利用、电荷有效分离与收集，申请人拟构建三维联通的石墨烯网络，作为半导体的载体，通过多种吸光材料的负载，集成出宽光谱太阳电池。主要研究内容：（1）探索石墨烯薄膜的低温PECVD生长。通过研究"等离子体-制备条件-成核生长"的动力学过程，发展石墨烯低温制备的新方法。（2）新型"Smart Substrate"复合衬底设计。利用金属不同碳溶解度和扩散率，设计双元金属、金属-绝缘体的智能复合衬底，结合PECVD技术，进行石墨烯的低温生长。（3）衬底孔道结构设计与三维石墨烯制备。借助于多孔陶瓷和粉末冶金制备技术，研制特定孔结构的衬底，基于上述基础，制备三维联通的石墨烯网络。（4）新型宽光谱太阳电池集成。基于石墨烯/光电转换材料的复合设计，以三维石墨烯为导电骨架，以不同吸光材料作为载体，制备三维石墨烯宽光谱型器件。

本项目聚焦石墨烯薄膜的低温生长和三维石墨烯网络结构的构建，协同调控石墨烯生长过程中互为影响的多个物理量，系统开展新型材料体系的设计制备和性能表征，并结合光伏材料实现其在太阳能电池中应用。项目共发表包括Science在内的SCI论文93篇、申请专利13项，出版专著1个章节；培养博士生5名、硕士生3名。（1）基于等离子体增强化学气相沉积技术和“Smart Substrate”复合衬底设计理念，实现了Al2O3、 BN等绝缘衬底上高质量石墨烯薄膜的低温可控制备；（2）设计合成了一种具有高比表面积的氮掺杂有序介孔少层碳材料，碳的sp2杂化程度高达98%，相关研究成果发表于《科学》（Science 2015, 350 (6267), 1508-1512）杂志上；（3）利用无机陶瓷、硝酸镁凝胶、有机聚合物、生物质等做为模板，实现了不同形貌三维石墨烯网络结构的可控制备，机械、吸附、导电、导热等性能大幅度提升；（4）设计合成了一系列新型硫属宽光谱光吸收材料，并对其光电效应进行了探讨；（5）成功制备了基于三维石墨烯结构的柔性太阳能电池，光电转换效率提高了54%。