Passivation of the Buried Interface via Preferential Crystallization of 2D Perovskite on Metal Oxide Transport Layers. Issue 41 (23rd August 2021)

• Record Type: Journal Article
• Authors: Chen, Bin; Chen, Hao; Hou, Yi; Xu, Jian; Teale, Sam; Bertens, Koen; Chen, Haijie; Proppe, Andrew; Zhou, Qilin; Yu, Danni; Xu, Kaimin; Vafaie, Maral; Liu, Yuan; Dong, Yitong; Jung, Eui Hyuk; Zheng, Chao; Zhu, Tong; Ning, Zhijun; Sargent, Edward H.
• Is Part Of: Advanced materials. Volume 33:Issue 41(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-23
• Subjects: interface passivation -- perovskites -- solar cells; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202103394
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: The open‐circuit voltage ( V oc ) of perovskite solar cells is limited by non‐radiative recombination at perovskite/carrier transport layer (CTL) interfaces. 2D perovskite post‐treatments offer a means to passivate the top interface; whereas, accessing and passivating the buried interface underneath the perovskite film requires new material synthesis strategies. It is posited that perovskite ink containing species that bind strongly to substrates can spontaneously form a passivating layer with the bottom CTL. The concept using organic spacer cations with rich NH2 groups is implemented, where readily available hydrogens have large binding affinity to under‐coordinated oxygens on the metal oxide substrate surface, inducing preferential crystallization of a thin 2D layer at the buried interface. The passivation effect of this 2D layer is examined using steady‐state and time‐resolved photoluminescence spectroscopy: the 2D interlayer suppresses non‐radiative recombination at the buried perovskite/CTL interface, leading to a 72% reduction in surface recombination velocity. This strategy enables a 65 mV increase in V oc for NiO x based p–i–n devices, and a 100 mV increase in V oc for SnO2 ‐based n–i–p devices. Inverted solar cells with 20.1% power conversion efficiency (PCE) for 1.70 eV and 22.9% PCE for 1.55 eV bandgap perovskites are demonstrated. Abstract : Interfacial nonradiative recombination limits the open‐circuit voltage of perovskite solar cells. A buried interface passivation strategy is developed that can be used across metal oxide transport layers. Perovskite precursors containing large organic cations with high affinity for the substrate spontaneously form a 2D passivation layer on the underlying metal oxides, which reduces interfacial recombination by 72%.