Self‐Encapsulating Thermostable and Air‐Resilient Semitransparent Perovskite Solar Cells

• Published in: Advanced energy materials 2017-07, Vol.7 (14), p.n/a
• Main Authors: Zhao, J., Brinkmann, K. O., Hu, T., Pourdavoud, N., Becker, T., Gahlmann, T., Heiderhoff, R., Polywka, A., Görrn, P., Chen, Y., Cheng, B., Riedl, T.
• Format: Article
• Language: English
• Subjects: Atomic layer epitaxy; Building envelopes; Decomposition; Electrical resistivity; Electrodes; Encapsulation; Metal films; permeation barrier; Perovskite; Perovskites; Photovoltaic cells; Protective coatings; semitransparent perovskite solar cells; Silver; Solar cells; stability; tin oxide; Transmittance; ultrathin silver
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201602599

Semitransparent perovskite solar cells (PSCs) are of interest for application in tandem solar cells and building‐integrated photovoltaics. Unfortunately, several perovskites decompose when exposed to moisture or elevated temperatures. Concomitantly, metal electrodes can be degraded by the corrosive decomposition products of the perovskite. This is even the more problematic for semitransparent PSCs, in which the semitransparent top electrode is based on ultrathin metal films. Here, we demonstrate outstandingly robust PSCs with semitransparent top electrodes, where an ultrathin Ag layer is sandwiched between SnOx grown by low‐temperature atomic layer deposition. The SnOx forms an electrically conductive permeation barrier, which protects both the perovskite and the ultrathin silver electrode against the detrimental impact of moisture. At the same time, the SnOx cladding layer underneath the ultra‐thin Ag layer shields the metal against corrosive halide compounds leaking out of the perovskite. Our semitransparent PSCs show an efficiency higher than 11% along with about 70% average transmittance in the near‐infrared region (λ > 800 nm) and an average transmittance of 29% for λ = 400–900 nm. The devices reveal an astonishing stability over more than 4500 hours regardless if they are exposed to ambient atmosphere or to elevated temperatures. SnOx/Ag/SnOx‐based semitransparent electrodes are used to prepare self‐encapsulated semitransparent perovskite solar cells, in which the SnOx grown by atomic layer deposition serves as a permeation barrier. The semitransparent cells show an efficiency of 11.8% and 29% average transmittance between 400 and 900 nm, realizing an outstanding stability over more than 4500 h in ambient air and at elevated temperatures.