碳基无空穴传输层钙钛矿太阳能电池(C-PSCs)因其替换了昂贵的贵金属电极,以及去掉了稳定性差的空穴传输材料而受到广泛关注.但是C-PSCs内部载流子分离和传输性能差阻碍了效率的提高,而内建电场的增强可以改善载流子传输性能从而提升电池光电性能.本文将铁电材料钛酸钡(BaTiO3)粉末作为添加剂引入钙钛矿前驱液中制备C-PSCs,改善钙钛矿薄膜形态,降低薄膜缺陷密度及提高C-PSCs载流子传输性能.结果表明,当BaTiO3 质量分数为 1.0%时,钙钛矿薄膜均匀致密,电池的光电转换效率最高.对薄膜施加正向电压极化处理后,铁电材料BaTiO3 剩余极化电场增大了内建电场,为载流子输运和萃取提供充足的动力,从而抑制非辐射复合的发生;同时耗尽层宽度增大,反向饱和电流减小,电池性能显著提升,优化后最佳器件效率为9.02%.本文为钙钛矿吸收层掺杂实现内建电场调控提供了一种有效策略.
The preparation of hybrid perovskite solar cells is expensive and environmentally demanding.Carbon-based HTL-free perovskite solar cells(C-PSCs)have attracted much attention because they replace the expensive precious metal electrode and remove the poor stability of the hole transport material.However,the improvement of efficiency is hampered by poor carrier separation and transport performance within C-PSCs,while the enhancement of the built-in electric field can improve the carrier transport performance,thus enhancing photoelectric performance.The built-in electric field can be regulated by doping.The anomalous photovoltaic effect and the built-in electric field of ferroelectric material play an important role in the field of optoelectronics.In this work,a simple and effective method is developed to improve the performance of perovskite solar cells via the combination of internal doping of ferroelectric polymer and external control of electric field.Ferroelectric material barium titanate(BaTiO3)powder is added into perovskite precursor solution as an additive to prepare C-PSCs,which can improve the perovskite film morphology,reduce the film defect density,and enhance the carrier transport performance of C-PSCs.The results show that when the addition of BaTiO3 is 1.0%(mass fraction),the perovskite film is uniform and dense,and the photoelectric conversion efficiency of the cell is the highest.After the forward voltage polarization treatment,the residual polarized electric field of ferroelectric material BaTiO3 increases the built-in electric field,which provides sufficient power for realizing carrier transport and extraction,thus inhibiting the occurrence of non-radiative recombination.At the same time,the depletion layer width is increased,and the reverse saturation current is reduced,so the cell performance is significantly improved.The optimal device efficiency is 9.02%.This work provides an efficient strategy for regulating the built-in electric field by doping perovskite absorption layer.