Sandwiched electrode buffer for efficient and stable perovskite solar cells with dual back surface fields

doi:10.1016/j.joule.2021.06.001

Joule

Volume 5, Issue 8, 18 August 2021, Pages 2148-2163

https://doi.org/10.1016/j.joule.2021.06.001 Get rights and content

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Highlights

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SEB provides better band alignment to improve carrier transport via dual BSFs
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SEB passivates various defects to improve carrier lifetime via multiple bonding
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SEB impedes mass loss, ion migration, and electrode diffusion in PSCs
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Over 97% of the initial PCE (23.9%) was retained after 2,000 h of MPP tracking

Context & scale

Perovskite solar cells (PSCs) require both high efficiency and sufficient stability simultaneously for their real-life applications. The back surface field (BSF) technique has been successfully adopted in crystalline silicon solar cells to dominate the photovoltaic market. We start up with this well-established idea of BSF, which is further replenished with passivation and stabilization that is urgently required for PSCs.

A sandwiched electrode buffer (SEB) is proposed to bridge perovskite absorber to metal contact in PSCs, wherein dual BSFs are implemented. This novel SEB adjusts the band alignment and passivates multiple defects for efficient carrier extraction and transport. Moreover, it effectively impedes mass loss and ion migration of the perovskite, protects the HTL from moisture attack, and prevents the electrode from diffusing. This demonstration provides an effective strategy to address both efficiency and stability concerns simultaneously, which pushes forward the commercialization of PSCs.

Summary

With the rapid progress of perovskite solar cells (PSCs), both high efficiency and sufficient stability are required simultaneously for their real-life application, wherein interfaces play an essential role. In this work, we develop sandwiched electrode buffer (SEB) with respect to the hole-transport layer (HTL), wherein dual back surface fields are implemented at two interfaces in relevance. The SEB bridges the absorber to the back electrode with the desired band alignment and multi-defect passivation effects, which stabilize the perovskite, HTL, and metal electrodes. Accordingly, planar n-i-p PSCs with SEB achieve an efficiency of 23.9% (certified 23.4%). Notably, they exhibit a remarkable operational stability with only a 3% efficiency decline for 2,000 h maximum power point tracking under 1-Sun illumination. Furthermore, the devices also show excellent thermal stability and humidity stability. Therefore, the SEB configuration boosts both efficiency and stability of PSCs, which paves the way for the commercialization of perovskite optoelectronics.

Graphical abstract

Keywords

perovskite solar cell

back surface field

electrode buffer

defect passivation

ion migration

high efficiency

stability

interface

Cited by (0)

⁷: These authors contributed equally

⁸: Lead contact