Details

Autor(en) / Beteiligte

• Caprioglio, Pietro
• Zu, Fengshuo
• Wolff, Christian M.
• Márquez Prieto, José A.
• Stolterfoht, Martin
• Becker, Pascal
• Koch, Norbert
• Unold, Thomas
• Rech, Bernd
• Albrecht, Steve
• Neher, Dieter

Titel

High open circuit voltages in pin-type perovskite solar cells through strontium addition

Ist Teil von

• Sustainable energy & fuels, 2019, Vol.3 (2), p.550-563

Ort / Verlag

London: Royal Society of Chemistry

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The incorporation of even small amounts of strontium (Sr) into lead-base hybrid quadruple cation perovskite solar cells results in a systematic increase of the open circuit voltage ( V oc ) in pin-type perovskite solar cells. We demonstrate via absolute and transient photoluminescence (PL) experiments how the incorporation of Sr significantly reduces the non-radiative recombination losses in the neat perovskite layer. We show that Sr segregates at the perovskite surface, where it induces important changes of morphology and energetics. Notably, the Sr-enriched surface exhibits a wider band gap and a more n-type character, accompanied with significantly stronger surface band bending. As a result, we observe a significant increase of the quasi-Fermi level splitting in the neat perovskite by reduced surface recombination and more importantly, a strong reduction of losses attributed to non-radiative recombination at the interface to the C 60 electron-transporting layer. The resulting solar cells exhibited a V oc of 1.18 V, which could be further improved to nearly 1.23 V through addition of a thin polymer interlayer, reducing the non-radiative voltage loss to only 110 meV. Our work shows that simply adding a small amount of Sr to the precursor solutions induces a beneficial surface modification in the perovskite, without requiring any post treatment, resulting in high efficiency solar cells with power conversion efficiency (PCE) up to 20.3%. Our results demonstrate very high V oc values and efficiencies in Sr-containing quadruple cation perovskite pin-type solar cells and highlight the imperative importance of addressing and minimizing the recombination losses at the interface between perovskite and charge transporting layer.