Role of surface recombination in perovskite solar cells at the interface of HTL/CH3NH3PbI3

• Published in: Nano energy Vol. 67; p. 104186
• Main Authors: Głowienka, Damian, Zhang, Dong, Di Giacomo, Francesco, Najafi, Mehrdad, Veenstra, Sjoerd, Szmytkowski, Jȩdrzej, Galagan, Yulia
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2020
• Subjects: Dead layer recombination; Interface recombination; Perovskite solar cell; Perovskite solar cell; Interface recombination; Dead layer recombination
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2019.104186

In order to achieve the highest performance of organometal trihalide perovskite solar cells, it is required to recognize the dominant mechanisms which play a key role in a perovskite material. In the following studies, we have focused on the interfacial recombination between the hole transporting layer (HTL) and the perovskite CH3NH3PbI3 in solar cell devices with p–i–n architecture. It has been shown that Cu:NiOx used as HTL drastically decreases a short–circuit photocurrent (Jsc) and an open–circuit voltage (Voc). However, we have found that an addition of PTAA thin layer improves cells quality and, as a consequence, the efficiency of such solar cells increases by 2%. Here, we explain both Jsc and Voc losses with a theory of the “dead layer” of perovskite material where a very high surface recombination occurs. We demonstrate the numerical and experimental studies by the means of series detailed analyses to get in–depth understanding of the physical processes behind it. Using a drift–diffusion model, it is shown that the presence of a parasitic recombination layer influences mostly the current distribution in the simulated samples explaining Jsc and Voc losses. The following results could be useful for improving the quality of perovskite solar cells. [Display omitted] •Interfacial recombination with the theory of the “dead layer” is studied.•Very high surface recombination in the dead layer leads to the Voc and Jsc losses.•Passivation with PTAA thin layer reduces the surface recombination and increases the efficiency of such solar cells by about 2%.•The electrical drift–diffusion model is used to prove the concept of recombination layer.