Enhancing stability and efficiency of perovskite solar cells with crosslinkable silane-functionalized and doped fullerene.

Yang Bai,Yehao Deng,Jinsong Huang,Dong Wang,Qi Wang,Qingfeng Dong,Wei Wei,Liang Shen,Yuchuan Shao

doi:10.1038/ncomms12806

Yang Bai, Yehao Deng + Show 7 more

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https://doi.org/10.1038/ncomms12806

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Journal: Nature Communications	Publication Date: Oct 5, 2016
Citations: 358	License type: CC BY 4.0

Affiliation: University of Nebraska–Lincoln

Abstract

The instability of hybrid perovskite materials due to water and moisture arises as one major challenge to be addressed before any practical application of the demonstrated high efficiency perovskite solar cells. Here we report a facile strategy that can simultaneously enhance the stability and efficiency of p–i–n planar heterojunction-structure perovskite devices. Crosslinkable silane molecules with hydrophobic functional groups are bonded onto fullerene to make the fullerene layer highly water-resistant. Methylammonium iodide is introduced in the fullerene layer for n-doping via anion-induced electron transfer, resulting in dramatically increased conductivity over 100-fold. With crosslinkable silane-functionalized and doped fullerene electron transport layer, the perovskite devices deliver an efficiency of 19.5% with a high fill factor of 80.6%. A crosslinked silane-modified fullerene layer also enhances the water and moisture stability of the non-sealed perovskite devices by retaining nearly 90% of their original efficiencies after 30 days' exposure in an ambient environment.

Highlights

The instability of hybrid perovskite materials due to water and moisture arises as one major challenge to be addressed before any practical application of the demonstrated high efficiency perovskite solar cells
The highest efficiency obtained in mesoscopic type devices is already higher than the commercial CIGS and CdTe thin film solar cells, the intrinsic instability of perovskite devices owing to moisture and water hampers their practical application in ambient conditions[19,20,21]
Though the moisture stability of perovskite film was improved in those designs, the widely used spiro-OMeTAD hole transport layers (HTLs) still limit the device stability due to the moisture affinity of Li salt dopants[19,20,21]

Summary

Introduction

The instability of hybrid perovskite materials due to water and moisture arises as one major challenge to be addressed before any practical application of the demonstrated high efficiency perovskite solar cells. A crosslinked silane-modified fullerene layer enhances the water and moisture stability of the non-sealed perovskite devices by retaining nearly 90% of their original efficiencies after 30 days’ exposure in an ambient environment. One strategy is to develop new two-dimensional layered perovskite materials, such as (C6H5(CH2)2NH3)2(CH3NH3)2[Pb3I10] Though this layered perovskite film showed enhanced moisture resistivity, the enlarged bandgap and exciton binding energy resulted in a low power conversion efficiency (PCE) of only 4.4% It is still essential and urgent to develop a facile route for enhancing the moisture resistance of perovskite devices without sacrificing photovoltaic performance In this manuscript, we report a water-resistant crosslinkable silane-functionalized fullerene ETL to improve the moisture stability of p–i–n planar perovskite solar cells. The combination of crosslinking and doping has resulted in both high efficiency and stable perovskite solar cells in an ambient environment without resorting to encapsulation techniques

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