基于TOPCon技术的梯度掺杂型p-NiOx/n-c-Si太阳电池的构筑及界面电荷行为机理研究

Insufficient charge transport capacity of hole-selective layer and large interface recombination at heterojunction interface are the key issues limiting the photovoltaic performance of TMOs/n-c-Si solar cells. In this project, we intend to prepare gradient doped p-NiOx hole-selective layer and develop TOPCon technique to construct high performance p-NiOx/n-c-Si solar cells; In-depth study the influence of the gradient doping model and the preparation process of p-NiOx hole-selective layer on the material properties, device built-in electric field, and interface-charge transport; Systematically investigate the synergistic effects between interface passivation and carrier tunneling-transport, which introduced by TOPCon technique; explore the dynamic process of carrier transport and recombination at p-NiOx/n-c-Si heterojunction interface during photoelectric conversion. We also aiming to optimize the adaptability between each functional layers to push the efficiency of prototype p-NiOx/n-c-Si solar cell >19%. The results of this research not only provide a solution to improve the photovoltaic performance of novel p-NiOx/n-c-Si solar cells, but also provide experimental basis and theoretical guidance for designing of carrier selection layer and interface optimization of other solar cells.

TMOs/n-c-Si太阳电池空穴选择层电荷输运性质差及异质结界面复合损失大是限制其光伏性能提升的关键问题所在。本课题拟制备梯度掺杂型p-NiOx空穴选择层，结合TOPCon界面钝化技术，构筑高性能p-NiOx/n-c-Si太阳电池；深入研究p-NiOx空穴选择层的梯度掺杂模型及制备工艺对材料光电特性、器件内建电场及界面电荷输运的影响机理；系统研究TOPCon工艺参数对异质结界面钝化性能及载流子隧穿输运效果的协同影响规律，并探究光电转换过程中p-NiOx/n-c-Si异质结界面的光生载流子的传输及复合的动力学过程；进行器件各功能层之间的适配性优化，制备效率>19%的p-NiOx/n-c-Si太阳电池原型器件。本课题研究结果不仅为提升新型p-NiOx/n-c-Si太阳电池光伏性能提供解决方案，也为其他类型电池的载流子选择层设计及界面优化提供一定的实验依据和理论指导。

以过渡金属氧化物(Transition Metal Oxides, TMOs)为电荷选择层的TMOs/n-c-Si太阳电池因其独特的光学及电学特性而受到广泛的关注。目前TMOs材料的电荷传输性能及异质结界面能级结构匹配问题是限制电池转换效率的关键因素。在本项目的支持下，我们以同步降低电池窗口层寄生吸收、提高界面电荷传输效率、改善界面能级结构、抑制界面复合损失为目标，通过设计不同光电特性、掺杂梯度、复合结构的多功能电荷传输材料，构建梯度p-NiOx、m-TiO2/a-WOx等梯度空穴(电子)选择层的异质结太阳电池，并提出异质结界面梯度模型及关键制备技术，发现NiOx:Cu/NiOx的最优梯度配位为3:1；而后为进一步解决异质结界面复合损失问题，引入了基于超薄SiOx钝化的TOPcon技术，发现2 nm的超薄SiOx可以实现界面电荷隧穿与缺陷钝化直接的平衡，在不损失界面电荷传输性能的前提下，有效钝化界面缺陷，改善p-NiOx/n-c-Si界面复合损失，获得转换率为20.3%的p-NiOx/n-c-Si异质结太阳电池 (其中，开路电压 0.682 V，填充因子76.02 %，短路电流密度39.15 mA/cm2 )。此外，项目还进一步探索了梯度电荷传输层在钙钛矿太阳电池中的应用，获得效率大于21.6%的转换效率，揭示了钙钛矿太阳电池内建电场、化学钝化、界面场钝化对光生电荷抽取的协同作用机理，为推动新型光伏器件的实际应用提供一定的理论依据和实验指导。