Key takeaways:
Hangzhou First presented encapsulant and sealant materials designed for perovskite and perovskite-silicon tandem modules
The materials are aimed at improving moisture resistance, UV protection, and compatibility with low-temperature processing
Low-temperature processing and moisture-barrier performance remain key focus areas for tandem-compatible encapsulation materials
It is common knowledge that perovskite and perovskite-silicon tandem technologies are sensitive to moisture, oxygen, UV, and heat. This is mainly attributed to the perovskite material. Therefore, PV modules made with perovskite or perovskite-silicon tandem cells need an effective first line of defense: a durable encapsulant that prevents these elements from reaching the perovskite material.
To address these issues, companies such as Hangzhou First are working to develop encapsulants that are compatible with perovskite materials and cell processes, and that avoid performance issues in final modules. Bo Jin, the company’s Sales Manager, presented encapsulant solutions developed for perovskite and perovskite tandem technologies at the TaiyangNews Next-Generation PV Technology Conference 2026.
Hangzhou First developed 2 products – an encapsulant and a sealant – whose ultimate goal is to serve as barriers while providing process compatibility during module assembly. Marketed under the brand name XUR 150, the encapsulant is a thermoplastic polyolefin (TPO) and is available in 3 variants with different melting points – 75°C, 97°C, and 107°C. These are applicable to different lamination temperature ranges between 100-200°C, 110-130°C, and 120-140°C.
Reliability tests, such as damp heat (DH2000) and HF cycles, were conducted to measure peel strength against glass, and after the test cycles, the strength remained above 40 N/cm. The yellowness index (∆YI) after DH3000, 60 HF cycles, and after 100 kWh UV irradiation was still below 1.5.
The edge sealant material developed by Hangzhou First is branded as PIB-405, which is available in glue, tape, and patch formats. This material is made of long-chain polyisobutylene resins and a large number of symmetric short-chain methyl groups on the sides. This enables a dense distribution of the material, creating a moisture barrier. A coupling agent is used in this resin to improve the sealant’s adhesion. Moisture or water vapor transmission rate (WVTR) is measured for this material under 100% relative humidity (RH) at 85, and it was found to be less than 5 g/m² in 24 hours. This is similar to a crosslinking POE but way better than a crosslinking EVA (25-30 g/m²/24h). The sealant was also tested under DH4000 on encapsulated samples containing color indicator papers, resulting in a minor color change. Additional tests, such as shear and peel strengths, were performed: shear strength exceeded 100%, and peel strength remained above 20 N/cm. Thermal and HF cycle tests, along with UV and DH tests on module samples, showed no delamination, no bubble formation, and no color change in the indicator paper.
Jin also presented advanced material solutions, called generation 2.0, that take into account the UV sensitivity of perovskite cells. For this, the front-side substrate of perovskite is stacked with an additional UV-cut EVA film followed by a UV-cut front glass cover. For a 4T tandem cell, the company also provides a low-temperature crosslinking EVA for the rear side and an insulation-enhanced TPO layer between silicon and perovskite cells. Jin also highlighted a solution for zero-busbar (0BB) tandem cells that is compatible with 0BB foil and favorable for low-temperature processes. These advanced products are available on the market; however, there is very little demand in the current scenario.
Jin's full talk titled Encapsulation Solutions for Perovskite Modules can be accessed here.