Suppressed Gold Penetration with the Molybdenum Oxide Interlayer to Increase Power Conversion Efficiency of Perovskite Solar Cells

Perovskite solar cells (PSCs) have undergone an unprecedentedly rapid development in both power conversion efficiency (PCE) and operational durability. However, a number of unknown challenges remain before PSC products are ready to launch. Herein, it is demonstrated that the vacuum deposition of gold (Au) onto the organic hole-transport layer (HTL) results in Au penetration into the perovskite layer. This Au penetration proves to be a limiting factor in PCE due to detrimental carrier recombination caused by the penetrated Au component inside the perovskite light absorber. To mitigate this issue, a thin molybdenum oxide (MoOx) interlayer between the organic HTL and the Au electrode is introduced, effectively reducing the Au penetration and suppressing the carrier recombination. Consequently, this MoOx introduction increases PCEs from approximate to 16.9% to approximate to 19.6% by approximate to 2.7%. Furthermore, using the MoOx interlayer improves the long-term durability of PSCs. These findings are crucial in elucidating a basic mechanism that limits PCE and in advancing the fabrication of PSC products with even higher performance. Gold (Au) penetration into the perovskite light absorber during vacuum deposition of the Au electrode on top of 2,2 ',7,7 '-tetrakis(N,N-di-p-methoxyphenylamine)-9,9 '-spirobi-fluorene (spiro-OMeTAD) hole transport layer induces detrimental carrier recombination. Inserting the molybdenum oxide interlayer between the spiro-OMeTAD layer and the Au electrode reduces the amount of the penetrated Au component, increasing PCEs from approximate to 16.9% to approximate to 19.6%.image (c) 2024 WILEY-VCH GmbH