有机光伏电池中基于光吸收增益的电极结构设计的研究

Organic photovoltaics (OPVs) have attracted intensive attention because of their unique advantages including low cost, easy process and compatibility with flexible substrates. Due to its potential for the most promising next-generation solar cell products, OPVs have been become a research focus. Sufficient absorption of incident light for the absorption layer is the key to improve the cell efficiency. The absorption layer thickness of OPVs is subject to the restriction for the increased recombination probability of photogenerated carriers, thereby constraining the sufficient light absorption. The introduction of light-trapping electrode structure into OPV can allow to fully absorb light without increasing the absorption layer thickness, but reduce the recombination probability of charge carriers. This project suggests the normal and inverted device structure based on the incident electrode and diffuse reflection of the back electrode, respectively. This project also focuses on revealing the mechanism of light-trapping electroede structure to improve the efficiency of light absorption, and exploring the structural design of OPVs with the scattering front electrode and the diffuse reflection back electrode, respectively. The final aim is the fabrication of prototype devices based on the normal and inverted structure of front scattering and back diffuse electrodes. The project takes into account the light-trapping structure of the electrodes which not only improve the light absorption, but also do not affect the transport and collection of the photogenerated carrier. The purpose of this project is to improve the overall device performance, and to pave the foundation for the further improved the light absorption and efficiency of OPVs.

有机光伏电池由于成本低、工艺简单、与柔性衬底相兼容等独特优势而倍受青睐；也最有望率先实现商业化而成为研究热点。吸光层对入射光的充分吸收是提高电池效率的关键。在有机光伏电池中，增加吸光层的厚度虽然能增强光的吸收，但受到光生载流子复合几率增加的影响，反而使电池的效率降低。本项目拟通过对电极结构设计来实现在不增加吸光层厚度的条件下，实现对光谱的充分吸收。提出分别设计前散射电极和背漫反射电极的正反型器件结构，揭示电极结构设计对光吸收增益的作用机制，探索并研究分别适用于正反型结构的有机光伏电池的前电极和背电极的结构设计，并最终制备出基于此光吸收增益效果的正反型有机光伏器件。本研究既考虑电极设计对光吸收增益的影响，还考虑其结构设计对电极的界面接触，载流子传输和收集的影响。本项目的最终目的是提高器件的整体性能，为进一步提高有机光伏电池的光吸收和效率奠定基础。

有机太阳能电池由于成本低、工艺简单等优势而倍受青睐成为研究热点。在有机光伏电池中吸光层的厚度对电池性能的影响是至关重要的。增加吸收层的厚度虽然能增强光的吸收，但也会增加光生载流子复合几率。本项目通过对电极结构设计来实现在不增加吸光层的厚度的条件下，实现对光谱的充分吸收。分别设计了前散射电极和背漫反射电极的器件结构，并应用到有机聚合物电池中，揭示了陷光电极结构对光吸收增益的机制，制备出基于前散射和背漫反射结构的有机太阳电池原型器件。本研究既考虑陷光电极对光吸收增益的影响，还考虑其结构设计对电极的界面接触，载流子传输和收集的影响。实验证明纳米绒面的前电极，覆盖在前电极上的亚微米绒面光吸收层以及微米绒面的背反电极三者的有效结合能显著增强对太阳光谱光的吸收，从而极大增加电池的短路电流密度，改善电池的光电转换效率。通过绒面电极的设计和改性提高了电池的整体器件性能，为进一步提高电池的光吸收和效率奠定了基础。