Flexible perovskite/silicon tandem solar cell with a dual buffer layer
Summary
This work introduces a dual-buffer-layer design to tackle mechanical stress and interfacial delamination in flexible perovskite/silicon tandem solar cells. The authors engineer two SnOx layers: a loose SnOx produced by tuning atomic layer deposition (ALD) purge time to dissipate strain energy, and a compact SnOx to provide robust electrical contact and preserve charge extraction.
The flexible tandem is built on a 60-μm ultra-thin silicon bottom cell and achieves certified power conversion efficiencies (PCE) of 33.4% on 1 cm2 and 29.8% on a 260 cm2 wafer-sized device, with a power-per-weight up to 1.77 W/g. Devices show excellent mechanical and thermal durability, retaining over 97% of initial PCE after 43,000 bending cycles (curvature radius ≈ 40 mm) and after 250 thermal cycles between −40 °C and 85 °C.
The dual-buffer strategy also reduces ion-bombardment damage during subsequent sputter deposition and strengthens interfacial adhesion without compromising electrical performance.
Key Points
- Dual SnOx buffer layers: a loose, strain-dissipating layer plus a compact, conductive layer to balance mechanical relief and electrical contact.
- Fabrication control achieved by adjusting ALD purge time to create the loose SnOx layer.
- High certified efficiencies: 33.4% (1 cm2) and 29.8% (260 cm2 wafer-sized).
- Lightweight devices: power-per-weight up to 1.77 W/g, relevant for mobile or weight-sensitive applications.
- Outstanding mechanical durability: >97% PCE retention after 43,000 bending cycles (≈40 mm radius).
- Thermal stability: ≈97% PCE retention after 250 cycles from −40 °C to 85 °C.
- Solution addresses ion-bombardment damage during sputtering and reduces interfacial delamination—key failure modes for flexible tandems.
Context and relevance
Perovskite/silicon tandems are among the most promising routes to exceed single-junction silicon efficiency. However, making them flexible and durable has been held back by interfacial stress, delamination and damage from deposition steps. This paper provides a pragmatic materials-engineering solution that is compatible with standard thin-film processing (ALD and sputtering) and demonstrates both high efficiency and real-world durability metrics on both small and wafer-scale devices. That combination — efficiency, scale and mechanical robustness — matters for commercialisation pathways (portable power, building-integrated PV, flexible modules).
Author style
Punchy: This is not just another efficiency number — the team demonstrate a clear, process-compatible fix for a mechanical failure mode that has plagued flexible tandem work. Because the approach is straightforward (tuning ALD purge time to make a compliant layer plus a compact contact layer), it’s immediately actionable for groups and companies scaling flexible tandem modules.
Why should I read this
Short version: they fixed a major pain point for flexible tandems without trading away efficiency. If you care about robust, lightweight, high-efficiency solar — whether for research, product development or supply-chain planning — this paper shows a simple process tweak that yields certified top-end efficiencies and staggering bending resistance. Worth a skim if you’re curious; read in full if you work on flexible PV or tandem device integration.