Enhanced UV-light stability of planar heterojunction perovskite solar cells with caesium bromide interface modification

Abstract

Interfacial engineering has been shown to play a vital role in boosting the performance of perovskite solar cells in the past few years. Here we demonstrate that caesium bromide (CsBr), as an interfacial modifier between the electron collection layer and the CH3NH3PbI3−xClx absorber layer, can effectively enhance the stability of planar heterojunction devices under ultra violet (UV) light soaking. Additionally, the device performance is improved due to the alleviated defects at the perovskite-titania heterojunction and enhanced electron extraction

Efficient and Air‐Stable Mixed‐Cation Lead Mixed‐Halide Perovskite Solar Cells with n‐Doped Organic Electron Extraction Layers

“…We find the "SPO ratio" is closer to one for doped devices, implying a reduction in the trap-assisted recombination site density. [19] We would expect a lower trap density to also deliver an increase in V oc , which we do not observe in the measured J-V curves. However, in Figure 3b we also show the V oc over measured over time, where we observe that the V oc of the cell containing doped C 60 is higher than the V oc of the control cell.…”

“…[18][19][20] Recently, Yang and co-workers demonstrated that inorganic metal oxides can be employed as interfacial materials to enhance the air stability. [18] Bryant et.…”

“…Our perovskite cells composed of p and n-doped organic charge extraction layers are reasonably stable in air (which includes oxygen and moisture) and full spectrum sun light that includes the UV component, which indicates that the perovskite solar cells (this perovskite in this architecture) are not as sensitive to these environmental stressing components as previously thought. [18][19][20][21]49,54,64,65] 2. The n-doping of the C 60 appears to have a persistent beneficial effect over prolonged operation in air, indicating that the N-DPBI retains its doping function throughout the ageing test.…”

Research Update: Strategies for improving the stability of perovskite solar cells

“…76,77 The control devices, in which the perovskite was coated directly onto TiO 2 , were shown to degrade rapidly which the authors attribute to a UV-induced photo-oxidation process at the TiO 2 surface. 34 This vulnerability to UV-activated degradation processes at the TiO 2 interface was confirmed by Li et al 80 In this study, the authors were able to stabilize the perovskite absorber by inserting a thin layer of CsBr between TiO 2 and the perovskite, thus inhibiting the photocatalytic decomposition of the absorber. 80 Another strategy to impede performance losses due to photoactivated absorber degradation was demonstrated by Pathak et al, who doped the mesoporous TiO 2 2016) layer with aluminum.…”

Cesium lead halide ( CsPbX 3, X = Cl , Br, I) perovskite quantum dots-synthesis, properties, and applications: a review of their present status

“…17 Similarly, using cesium bromide (CsBr) and cesium chloride (CsCl) as modifiers, the organo lead halide perovskite-based planar heterojunction solar cells could deliver 16% and 16.8% efficiency with good stability. 18,19 A very recent analysis indicates that this efficiency increases to over 17% with the composition of Cs 0.2 FA 0.8 PbI 2. 84 Br 0.…”