Nano Letters published an article of Professor Hongwei Han's research group

Issuing time:2020-10-30 10:00

Stable electron transport materials (ETMs) with fewer surface defects and proper energy level alignments with halideperovskite active layers are required for ecient perovskite solar cells (PSCs) with long-term durability. Here,two-dimensional van der Waals mixed valence tin oxides Sn2O3and Sn3O4 are controllably synthesized and applied asETMs for planar PSCs. The synthesized Sn2O3 and Sn3O4have size of 520 nm and disperse well in water as stablecolloids for months. Both Sn2O3 and Sn3O4exhibit typical n-type semiconductor energy band structures, low trap density,and suitable energy level alignments with halide perovskites. Steady-statepower conversion eciencies (PCEs) of22.36% and 21.83% are obtained for Sn2O3-based and Sn3O4-basedplanar PSCs. In addition, the half cells without hole transport materials andback electrodes show good UV-stability with average PCE of 99.0% and 95.7% forSn2O3-based and Sn3O4-based devicesremaining after 1000 h of ultraviolet soaking with an intensity of 70 mW cm2.


(a) Photos of SnO2, Sn2O3,and Sn3O4 dispersions and SnO precipitation in water. (b)Photos of powders obtained by freeze-drying. (cf)Theoretical crystal structure of (c) SnO2, (d) Sn2O3,(e) Sn3O4 and (f) SnO. (g) Band alignments with halideperovskites. (h) JV curves of PSCs based on three tin oxides at reverse sweep.

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