Suppression of non-radiative recombination with efficient doping of Spiro-OMeTAD for high-performance perovskite solar cells

Abstract

Metal-halide perovskite solar cells (PSCs) have attracted considerable attention during the past decade. However, due to the existence of non-radiative recombination losses, the best power conversion efficiency (PCE) is still lower than the theoretical limit defined by Shockley-Queser theory. In this work, we investigate 1,2,3-oxathiazin-4(3h)-one, 6-methyl-2,2-dioxide (acesulfame potassium, abbreviated as AK) as a additional dopant for the 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (Spiro-OMeTAD) and fabricate PSCs in the air. It is found that 12 mol% fraction of AK relative to lithium bis((trifluoromethyl)sulfonyl)-amide (Li-TFSI) reduces the non-radiative recombination from 86.05% to 69.23%, resulting in an average 0.08 V of Voc enhancement. The champion solar cell gives a perovskite solar cells up to 21.9% and over 84% retention of the initial value during 720 h aging in dry air with 20%-30% humidity.