Stolterfoht Martin, Grischek Max, Caprioglio Pietro, Wolff Christian M, Gutierrez-Partida Emilio, Peña-Camargo Francisco, Rothhardt Daniel, Zhang Shanshan, Raoufi Meysam, Wolansky Jakob, Abdi-Jalebi Mojtaba, Stranks Samuel D, Albrecht Steve, Kirchartz Thomas, Neher Dieter
Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam-Golm, D-14476, Germany.
Young Investigator Group Perovskite Tandem Solar Cells, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Kekuléstraße 5, Berlin, 12489, Germany.
Adv Mater. 2020 Apr;32(17):e2000080. doi: 10.1002/adma.202000080. Epub 2020 Mar 12.
Perovskite photovoltaic (PV) cells have demonstrated power conversion efficiencies (PCE) that are close to those of monocrystalline silicon cells; however, in contrast to silicon PV, perovskites are not limited by Auger recombination under 1-sun illumination. Nevertheless, compared to GaAs and monocrystalline silicon PV, perovskite cells have significantly lower fill factors due to a combination of resistive and non-radiative recombination losses. This necessitates a deeper understanding of the underlying loss mechanisms and in particular the ideality factor of the cell. By measuring the intensity dependence of the external open-circuit voltage and the internal quasi-Fermi level splitting (QFLS), the transport resistance-free efficiency of the complete cell as well as the efficiency potential of any neat perovskite film with or without attached transport layers are quantified. Moreover, intensity-dependent QFLS measurements on different perovskite compositions allows for disentangling of the impact of the interfaces and the perovskite surface on the non-radiative fill factor and open-circuit voltage loss. It is found that potassium-passivated triple cation perovskite films stand out by their exceptionally high implied PCEs > 28%, which could be achieved with ideal transport layers. Finally, strategies are presented to reduce both the ideality factor and transport losses to push the efficiency to the thermodynamic limit.
钙钛矿光伏（PV）电池已展现出接近单晶硅电池的功率转换效率（PCE）；然而，与硅光伏不同的是，在1个太阳光照下，钙钛矿不受俄歇复合的限制。尽管如此，与砷化镓和单晶硅光伏相比，由于电阻性和非辐射复合损耗的综合影响，钙钛矿电池的填充因子显著更低。这就需要更深入地了解潜在的损耗机制，尤其是电池的理想因子。通过测量外部开路电压和内部准费米能级分裂（QFLS）的强度依赖性，可量化完整电池的无传输电阻效率以及任何有无附着传输层的纯钙钛矿薄膜的效率潜力。此外，对不同钙钛矿组成进行强度依赖性QFLS测量，能够区分界面和钙钛矿表面对非辐射填充因子和开路电压损失的影响。研究发现，钾钝化的三阳离子钙钛矿薄膜因其异常高的隐含PCE大于28%而脱颖而出，这在理想传输层的情况下是可以实现的。最后，提出了降低理想因子和传输损耗的策略，以将效率提升至热力学极限。
