Nature (IF 69.504): Research Team from KAUST Proposed Ultrathin IZO Contacts Enable Highly Efficient Perovskite/Silicon Tandems
Highlights
The research article was published by Stefaan De Wolf, Esma Ugur, Erkan Aydin, et al. from King Abdullah University of Science and Technology(KAUST).
- Monolithic perovskite/silicon tandem solar cells can achieve high power conversion efficiencies, but optimizing the interface between subcells is critical.
- Using an ultrathin (5nm) amorphous indium zinc oxide (IZO) interlayer improves electrical contact and self-assembled monolayer coverage between subcells.
- With optimized IZO interlayers and contact stacks, a perovskite/silicon tandem solar cell achieved a certified efficiency of 32.5%, among the highest reported.
- The thin IZO approach reduces indium consumption by ~80%, important for sustainable manufacturing.
Background
Perovskite/silicon tandem solar cells can reach high efficiencies by combining the complementary light absorption of the two materials. Connecting the perovskite and silicon subcells with a self-assembled monolayer (SAM) on a transparent conductor allows efficient charge transfer between the subcells. However, attaining uniform SAM coverage on textured silicon surfaces continues to pose difficulties for reproducible high-efficiency tandem cells. Researchers used an ultrathin amorphous indium zinc oxide interlayer to achieve excellent SAM coverage and coupling between subcells.
Results
- Monolithic perovskite/silicon tandem solar cells can achieve high power conversion efficiencies, but require uniform self-assembled monolayer (SAM) coverage on textured silicon for reproducible performance.
- Using an ultrathin (5nm) amorphous indium zinc oxide (IZO) interconnecting transparent conductive oxide (TCO) layer resolves the SAM coverage issue.
- IZO provides high surface-potential homogeneity and increased SAM anchoring sites compared to crystalline TCOs.
- Combining the 5nm IZO interconnect with optical enhancements enabled a record certified efficiency of 32.5% for perovskite/silicon tandems.
- The ultrathin IZO approach reduces indium consumption by ~80% compared to standard TCO thicknesses, enabling more sustainable PV manufacturing.
Methods
- Used 5nm ultrathin amorphous IZO as interconnecting TCO between subcells
- IZO enabled uniform SAM coverage and high density of anchoring sites
- Deposited thin IZO for rear silicon contact
- Optimized front contact stacks
- Fabricated monolithic perovskite/silicon tandem with IZO layers
- Independently certified power conversion efficiency
Conclusion
The ultrathin IZO interlayer approach developed by researchers resolves the issue of achieving uniform SAM coverage on textured silicon surfaces in monolithic perovskite/silicon tandem solar cells. This interfacial engineering with the amorphous IZO contacts enables highly efficient optoelectronic coupling between the perovskite and silicon subcells. A key sustainability benefit is that the thin IZO layers reduce indium consumption by around 80% compared to standard thicker contacts. Further interface optimization and efficiency improvements of these next-generation tandems are possible through this promising IZO interlayer strategy.
SI Fig. 5 | Electroluminescence analysis
SI Fig. 6 | MPPT analysis
