导电聚合物作为界面钝化层的非掺杂型硅异质结太阳电池研究

New generation silicon (Si) solar cells with dopant-free heterojunctions, which can reach both energy-consumption saving and procedures simplification, has attracted considerable attention for boosting the efficiency as well reducing the manufacturing costs. For this kind of heterojuncitons, it is hard for traditional dielectric passivation layer to simultaneously achieve both optimized carriers tunneling and minimized recombination loss. In this project, we propose a new type of carrier-selective heterojunction, MoOx/PEDOT:PSS/n-Si, with the highly hole-conductive polymer (PEDOT:PSS) as interfacial passivation-layer. Firstly, various means including modifications of Si surface, additions of polarity solvents into PEDOT:PSS solution, and post-treatments on PEDOT:PSS films with acting force, etc. to achieve fully physical contact between PEDOT:PSS and micro- or nano-structured Si surface. Secondly, combined with the characterizations of XPS, surface light voltage, minority carrier lifetime and photovoltaic parameters, to fully explore the effects of typical chemical treatments on the interface chemistry and electronic structure of PEDOT:PSS/n-Si, and further on the energy-band bending. Thirdly, the conductivity and work function of PEDOT:PSS and MoOx will be separately optimized by suitable chemical additions (phase separation) and tuning of the evaporation process, and their impacts on built-in potential and carrier collection capability of the heterojunction solar cells will be investigated in detail. Through the above research, general empirical theories for synchronously optimizing the built-in electric field, interfacial passivation quality and charge extraction ability for this kind of "conductive polymer passivated silicon heterojunctions", will be summed up as design guidance for developing high-performance and dopant-free heterojunction solar cells in cost-effective ways.

传统硅异质结太阳电池中的介电性界面层需要在载流子隧穿和钝化效果之间寻求最佳平衡，本项目提出用高空穴导电性聚合物作为界面钝化层构建以MoOx/PEDOT:PSS/n-Si为核心结构的非掺杂型异质结电池，拟结合硅表面改性、PEDOT:PSS溶液极性添加，及外加微应力的办法实现长链聚合物与微纳结构硅表面的全物理接触；结合XPS、表面光电压、少子寿命及电池参数表征，全方位考察典型化学处理对PEDOT:PSS/n-Si界面化学及电子结构的影响、进而对界面能带结构的作用效果；通过化学添加、蒸发工艺调节分别优化PEDOT:PSS及MoOx的电导率和功函数，并详细探讨它们对器件内建电压和载流子收集的不同作用机理。通过以上研究，总结出同步提升“导电聚合物钝化的非掺杂硅异质结”的内建电场电压、界面钝化质量和电荷提取能力的一般性经验理论，指导新型高性能硅异质结的设计，为太阳电池应用提供高效、低成本的核心技术。

传统硅异质结太阳电池中的介电性界面层需要在载流子隧穿和钝化效果之间寻求最佳平衡，本项目提出用高空穴导电性聚合物作为界面钝化层构建以MoOx/PEDOT:PSS/n-Si为核心结构的非掺杂型异质结电池，拟结合硅表面改性、PEDOT:PSS溶液极性添加，及外加微应力的办法实现长链聚合物与微纳结构硅表面的全物理接触；结合XPS、表面光电压、少子寿命及电池参数表征，全方位考察典型化学处理对PEDOT:PSS/n-Si界面化学及电子结构的影响、进而对界面能带结构的作用效果；通过化学添加、蒸发工艺调节分别优化PEDOT:PSS及MoOx的电导率和功函数，并详细探讨它们对器件内建电压和载流子收集的不同作用机理。通过以上研究，总结出同步提升“导电聚合物钝化的非掺杂硅异质结”的内建电场电压、界面钝化质量和电荷提取能力的一般性经验理论，指导新型高性能硅异质结的设计，为太阳电池应用提供高效、低成本的核心技术。.发展了系列高电荷选择比的晶硅异质结：（1）针对“聚合物/硅”的杂化异质结体系，通过功函数诱导、面电极设计、微应力调制、离子液体修饰等，把开路电压、填充因子和效率分别提升到660 mV、80.2%和16.7%，利用溶液法制备出最高效率的晶硅太阳电池；（2）通过异质结接触和电池结构设计，仅仅利用2次掩膜和低温蒸镀的无掺杂方法，制备出20.6%效率的全背面接触型太阳电池。所总结出的对现有空穴（电子）传输材料改性提升方法，以及同步降低复合速率和接触电阻的策略，对开发高性价比的新型高效晶体硅太阳电池具有重要指导价值。