Encapsulation Strategies for Highly Stable Perovskite Solar Cells under Severe Stress Testing: Damp Heat, Freezing, and Outdoor Illumination Conditions

Abstract

A key direction toward managing extrinsic instabilities in perovskite solar cells (PSCs) is encapsulation. Thus, a suitable sealing layer is required for an efficient device encapsulation, preventing moisture and oxygen ingression into the perovskite layer. In this work, a solution-based, low-cost, and commercially available bilayer structure of poly(methyl methacrylate)/styrene-butadiene (PMMA/SB) is investigated for PSCs encapsulation. Encapsulated devices retained 80% of the initial power conversion efficiency (PCE) at 85 °C temperature and 85% relative humidity after 100 h, while reference devices without SB (only PMMA) suffer from rapid and intense degradation after only 2 h, under the same condition. In addition, encapsulated devices retained 95% of the initial PCE under −15 °C freezing temperature after 6 h and retained ∼80% of the initial PCE after immersion in HCl (37%) for 90 min. Moreover, applying an additional aluminum metal sheet on the PMMA/SB protective bilayer leads to the improvement of device stability up to 500 h under outdoor illumination, retaining almost 90% of the initial PCE. Considering the urge to develop reliable, scalable, and simple encapsulation for future large-area PSCs, this work establishes solution-based bilayer encapsulation, which is applicable for flexible solar modules as well as other optoelectronic devices such as light-emitting devices and photodetectors.

Encapsulation and Stability Testing of Perovskite Solar Cells for Real Life Applications

“…However, a possible concern in polymer encapsulation is the solvent used for polymer coating, since it has been reported that poly­(methyl methacrylate) (PMMA) deposition from chlorobenzene solutions can result in damage to the 2,2’,7,7’-tetrakis­[ N , N -di­(4-methoxyphenyl)­amino]-9,9’-spirobifluorene (spiroOMeTAD) layer . Various polymers have been reported for the encapsulation of perovskite films and devices, such as PDMS, plasma polymer film from adamantane precursor, poly­(methylmethacrylate) (PMMA), ,− parylene C, TPU, PMMA/vulcanized silicone rubber, PMMA//styrene-butadiene (SB), fluoropolymer coating, etc. In addition to polymer films, roll-transferred graphene has also been used as well as spray-coated reduced graphene oxide (rGO) .…”

Tin-based halide perovskite materials: properties and applications

“…5a). Therefore, similar to Pb-based perovskites, [101][102][103] fully understanding the degradation mechanism is reasonably necessary to solve the stability issue in this type of perovskites. Generally, as discussed, the facile oxidation of Sn 2+ to Sn 4+ was identied as the main instability reason of these materials, which leads to deteriorating the thin lm morphology and optoelectronic properties, as well as high-density p-type doping.…”

Lamination methods for the fabrication of perovskite and organic photovoltaics

“…Inspired by the DSSCs sandwich device structure, the two TCO electrodes can be used as front and back electrodes to fabricate the PSC with self-encapsulation features to protect the devices from moisture and improve the device stability. 56,[107][108][109] Using this architecture, Heo et al fabricated semi-transparent planar sandwich PSCs with almost a hysteresis-free PCE of 15.8% and over 20 days of stability (5% dropped PCE) without any extra encapsulation. 56 They used semi-transparent FTO glass/TiO 2 /MAPbI 3 /HTL and ITO/PEDOT:PSS as the first and second stack, respectively.…”