Combination of Metal Oxide and Polytriarylamine: A Design Principle to Improve the Stability of Perovskite Solar Cells

Abstract

In the last decade, perovskite photovoltaics gained popularity as a potential rival for crystalline silicon solar cells, which provide comparable efficiency for lower fabrication costs. However, insufficient stability is still a bottleneck for technology commercialization. One of the key aspects for improving the stability of perovskite solar cells (PSCs) is encapsulating the photoactive material with the hole-transport layer (HTL) with low gas permeability. Recently, it was shown that the double HTL comprising organic and inorganic parts can perform the protective function. Herein, a systematic investigation and comparison of four double HTLs incorporating polytriarylamine and thermally evaporated transition metal oxides in the highest oxidation state are presented. In particular, it was shown that MoOx, WOx, and VOx-based double HTLs provided stable performance of PSCs for 1250 h, while devices with NbOx lost 30% of their initial efficiency after 1000 h. Additionally, the encapsulating properties of all four double HTLs were studied in trilayer stacks with HTL covering perovskite, and insignificant changes in the absorber composition were registered after 1000 h under illumination. Finally, it was demonstrated using ToF-SIMS that the double HTL prevented the migration of perovskite volatile components within the structure. Our findings pave the way towards improved PSC design that ensures their long-term operational stability.

Hole-transporting interlayers based on pyrazine-containing conjugated polymers for perovskite solar cells

“…39,40 A similar effect was also observed for this configuration of devices in our previous work. 33 Generally, the efficiency of PSCs with PTTA tends to decrease after 1100 h of operation, whereas PBPyT-based devices demonstrated high operational stability under continuous illumination, which is an encouraging result.…”

“…In order to estimate the potential of conjugated polymers PBPyT-ex and PBPyT-in as HTMs, PSCs with the n-i-p architecture of ITO/SnO 2 /PCBM/MAPbI 3 /HTM/MoO x /Ag were fabricated. 33 The details of PSC fabrication are described in the Experimental section. First, electron-transport layers SnO 2 and PCBM ( [6,6]-phenyl-C 61 butyric acid methyl ester) were spin-coated on the transparent conductive electron-collecting electrode ITO.…”

The Impact of Backbone Fluorination and Side-Chain Position in Thiophene-Benzothiadiazole-Based Hole-Transport Materials on the Performance and Stability of Perovskite Solar Cells

“…Therefore, for this experiment, devices with another configuration were fabricated. They consisted of more stable Cs(NH 2 ) 2 CHPbI 3 perovskite, ZnO as ETL, an Al electrode, and vanadium oxide as an inorganic component of the double hole-transport layer [ 14 ]. The evolution of the device efficiency under constant illumination is presented in Figure 5 b.…”

“…In recent work, it was demonstrated that the application of a double hole-transport layer comprising a combination of organic material and transition metal oxides in the highest oxidation state, such as molybdenum (VI) oxide, vanadium (V) oxide, and tungsten (VI) oxide allows the achievement of outstanding stabilities of PSCs up to 4500 h under operation conditions [ 13 ]. Furthermore, in our work it was revealed that, while double hole-transport layers with vanadium oxide perform as a perfect encapsulating layer, it is the organic component, which should be optimized further to improve the performance of PSCs [ 14 ].…”

Novel Push-Pull Benzodithiophene-Containing Polymers as Hole-Transport Materials for Efficient Perovskite Solar Cells

“…Hole-transporting materials (HTMs) also play a crucial role in boosting performance and improving the operational stability of PSCs. In particular, individual or double-layered HTMs based on a combination of metal oxides and organic polymers can prevent the migration of the volatile byproducts of perovskite reversible decomposition from the device, so they could participate in the perovskite formation reaction enabling improved operation stability of PSCs [ 3 , 4 ]. Many various organic HTMs have recently been developed and investigated in PSCs.…”