What are the latest advancements in encapsulation techniques for perovskite solar cells

Recent advancements in encapsulation techniques for perovskite solar cells (PSCs)

Recent advancements in encapsulation techniques for perovskite solar cells (PSCs) primarily focus on enhancing both the stability and efficiency of these devices by providing effective barriers against moisture, oxygen, and mechanical stress, while also addressing optical losses.

Latest Advancements in Encapsulation Techniques

1. One-Step Polydimethylsiloxane (PDMS) Encapsulation with Light Management

• Researchers at Aalto University developed a novel one-step encapsulation method using polydimethylsiloxane (PDMS) that coats the entire surface and edges of the perovskite solar cells.
• This encapsulant is patterned in situ via a soft lithography technique inspired by leek leaf structures to reduce reflection and increase light scattering (haze), thus improving light management.
• The method not only shields the solar cells from oxygen and moisture degradation but also provides anti-reflective properties, leading to an 8% relative improvement in power conversion efficiency—from 14.1% to 15.6%—compared to unencapsulated devices.
• The encapsulated cells passed rigorous stability tests, maintaining 80% of initial performance after 360 hours under light-dark cycling and surviving 90% relative humidity and water immersion tests. Outdoor tests also showed no degradation after exposure to low temperatures and wind.
• This PDMS encapsulation is flexible, suitable for both rigid and flexible PSCs, and does not require high-temperature processing or UV curing, making it scalable and adaptable for diverse applications.

2. Thin Film Encapsulation Using Polymers and Inorganic Layers

• Thin film encapsulation remains a key technique, especially for flexible and lightweight applications. Materials include polymers like poly(methylmethacrylate) (PMMA), parylene C, TPU, and fluoropolymer coatings. These polymers are deposited by low-cost, simple methods but must be carefully chosen to avoid solvent damage to perovskite layers.
• Inorganic thin films like alumina, silica, and vanadium oxide deposited via atomic layer deposition (ALD), e-beam evaporation, RF sputtering, or plasma-enhanced chemical vapor deposition provide strong moisture and oxygen barriers.
• Combining ALD alumina films with hydrophobic surface treatments (e.g., perfluorodecyltrichlorosilane) has been shown to improve barrier performance significantly against moisture ingress.
• Graphene-based layers, such as roll-transferred graphene or spray-coated reduced graphene oxide (rGO), have also been explored as novel encapsulants due to their excellent barrier properties and mechanical strength.
• These multi-layer and hybrid encapsulation approaches enhance the long-term stability of PSCs, enabling them to survive harsh environmental conditions like damp heat and outdoor testing.

3. Glass/Glass Encapsulation for Robust Protection

• Glass/glass encapsulation setups provide excellent physical and chemical barriers, effectively shielding PSCs from moisture and oxygen, and protecting against mechanical damage.
• This method is often used for rigid PSCs and is considered a good option for commercialization despite higher cost and weight compared to polymer encapsulation.

4. Encapsulation Tackling Lead Leakage and Sustainability

• New encapsulants are being researched not only to improve stability but also to minimize the potential lead leakage from PSCs, a critical environmental concern.
• Advanced encapsulation techniques aim to seal the perovskite materials hermetically, while maintaining device performance and recyclability.

Summary Table of Encapsulation Innovations

Outlook

The encapsulation of PSCs is advancing towards integrated solutions that combine stability enhancement, optical performance improvement, and environmental safety. The novel one-step light-managing PDMS encapsulation represents a promising scalable approach, while thin film and hybrid inorganic/polymer encapsulation remain important for flexible and lightweight applications. Alongside improved stability, efforts to improve recyclability and reduce toxic lead leakage are gaining traction to push PSCs closer to commercial viability.

This synthesis reflects the state-of-the-art encapsulation technologies for perovskite solar cells as of early 2025, highlighting the balance of protecting the delicate perovskite materials while enhancing device performance and durability.