Moisture tolerant solar cells by encapsulating 3D perovskite with long-chain alkylammonium cation-based 2D perovskite

Bhushan P Kore,Billy W Hoogendoorn,James M Gardner,Majid Safdari,Wei Zhang

doi:10.1038/s43246-021-00200-8

Bhushan P Kore, Billy W Hoogendoorn + Show 3 more

Open Access

https://doi.org/10.1038/s43246-021-00200-8

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Abstract

Long-term stability is an essential requirement for perovskite solar cells to be commercially viable. Encapsulating 3D perovskites with 2D perovskite structures is an effective strategy for improving resistance to moisture. However, long-chain alkylammonium cation-based 2D perovskites have been rarely studied in solar cells. Here, we study three different alkyl chain length organic cation-based 2D perovskite coatings for 3D perovskites. The 2D perovskite incorporated solar cells show significant improvement in solar cell stability with limited compromise in solar cell efficiency, with the longest alkyl chain length sample showing only a 20% drop in power conversion efficiency after 6 months at a relative humidity of 25-80%, and could be completely immersed in water for a few minutes before degradation started. The 2D perovskite coating also mitigated non-radiative recombination in the light-absorbing 3D perovskite, leading to an enhancement in the open circuit voltage. These findings suggest that long-chain alkylammonium cation based 2D perovskites can improve the environmental stability of 3D based perovskites without significant losses to device performance.

Highlights

Long-term stability is an essential requirement for perovskite solar cells to be commercially viable
Our work demonstrates that the use of a longcarbon-chain organic cation in 3D@2D heterostructures is possible without compromising the performance of the perovskite solar cell
The presence of long alkylammonium cations increases their desorption energy compared with the smaller cations like MA25, as a result, a more stabilized structure, which is even stable for days when completely immersed in water, is achieved[13]

Summary

Introduction

Long-term stability is an essential requirement for perovskite solar cells to be commercially viable. The 2D perovskite coating mitigated non-radiative recombination in the light-absorbing 3D perovskite, leading to an enhancement in the open circuit voltage These findings suggest that long-chain alkylammonium cation based 2D perovskites can improve the environmental stability of 3D based perovskites without significant losses to device performance. The presence of bulky organic cations in 2D structure hampers the charge transport, and as a result of this, the solar cell devices based on 2D perovskite materials have lower efficiencies compared with the pure three-dimensional (3D) perovskite-based solar cells[12,14,15] Due to these reasons, 2D perovskites are not usually used as primary absorbers in the active layers of PSCs. Recently, a lot of efforts have been focused on embedding 2D perovskites in 3D perovskite structure to achieve improved device stability without compromising the photovoltaic efficiencies

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