Details

Autor(en) / Beteiligte

• Wu, Zhifang
• Jiang, Maowei
• Liu, Zonghao
• Jamshaid, Afshan
• Ono, Luis K.
• Qi, Yabing

Titel

Highly Efficient Perovskite Solar Cells Enabled by Multiple Ligand Passivation

Ist Teil von

• Advanced energy materials, 2020-03, Vol.10 (10), p.n/a

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2020

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• In the past decade, the efficiency of perovskite solar cells quickly increased from 3.8% to 25.2%. The quality of perovskite films plays vital role in device performance. The films fabricated by solution‐process are usually polycrystalline, with significantly higher defect density than that of single crystal. One kind of defect in the films is uncoordinated Pb2+, which is usually generated during thermal annealing process due to the volatile organic component. Another detrimental kind of defect is Pb0, which is often observed during the film fabrication process or solar cell operation. Because the open circuit voltage has a close relation with the defect density, it is thus desirable to passivate these two kinds of defects. Here, a molecule with multiple ligands is introduced, which not only passivates the uncoordinated Pb2+ defects, but also suppresses the formation of Pb0 defects. Meanwhile, such a treatment improves the energy level alignment between the valence band of perovskite and the highest occupied molecular orbital of spiro‐OMeTAD. As a result, the performance of perovskite solar cells significantly increases from 19.0% to 21.4%. By introduction of a multiple ligand (pentaerythritol tetrakis(3‐mercaptopropionate)), uncoordinated Pb2+ and Pb0 defects are simultaneously passivated. Meanwhile, better energy level matching between the valence band of perovskite and the highest occupied molecular orbital of the HTM is achieved. As a result, perovskite solar cell efficiency increases from 19.0% to 21.4% after surface passivation by multiple ligands.