Versatile perovskite solar cell encapsulation by low-temperature ALD-Al₂O₃with long-term stability improvement

Abstract

A low temperature (60 °C) encapsulation process based on a single thin (16 nm) coating of Al2O3 prepared by atomic layer deposition.

Carbon-based materials for stable, cheaper and large-scale processable perovskite solar cells

“…UV light exposure has been identified as one of the key issues for the evaluation of PSCs' long-term stability. [168][169][170][171] For this reason, the same cells obtained by inkjet printing and stored without encapsulation were subjected to intense 1.5 sun UV light illumination in an electronic weather chamber, at 45% RH and 40 1C. 164 In the first 250 h, the cell ameliorated its performances in both J sc (+17%) and PCE (8.6%); this behavior may be ascribed to the additional curing of perovskite crystals under UV light.…”

Crystal Reorientation and Amorphization Induced by Stressing Efficient and Stable P–I–N Vacuum‐Processed MAPbI3 Perovskite Solar Cells

“…[44] There are also external factors that influence the stability of PSCs, such as light, heat, oxygen, and moisture; although the first two remain critical and unavoidable, the last two can be circumvented by proper encapsulation of the device in inert atmosphere gloveboxes right after fabrication. [12,45] Many types of encapsulation have been tested in PSCs using different shielding materials, [46] such as ethylene vinyl acetate, [47] UV-vis curable epoxy resins, [48,49] polymeric coatings, [50] adhesives, [51] and polymer/glass or polymer/metal plate stacks. [52,53] In special, atomic layer deposition (ALD) of moisture barrier layers is a wellknow encapsulation agent in organic light-emitting diodes (OLEDs).…”

“…[54] In ALD, ultrathin layers with atomic proportions are obtained by a sequential exposure of the substrate to gas phase precursors, in a self-limited controlled layer-by-layer deposition, enabling dense, pinhole-free inorganic films with high 3D conformality and excellent surface coverage. [46,55] The use of ALD for encapsulation is particularly interesting for PSCs to diminish the perovskite toxicity effects and their quick degradation in air, as reviewed by Zardetto et al [56] Among the many oxides obtainable by ALD, Al 2 O 3 is a versatile material that can be ALD-grown from trimethylaluminum (TMA) and water (or ozone) as precursors on top of different materials with all types of hydrophilicity and has a very-low water vapor transmission rate of 10 À6 g m À2 per day. [46] There are only a few works to report PSC stability improvements using ALD-coated Al 2 O 3 [46,[57][58][59][60][61] and the main drawbacks lie in the usual aggressive deposition conditions (mostly, the high temperature range typically applied in many ALD protocols, usually from 80 to 300 C) that can stress and degrade the perovskite underlayer, decreasing the initial preencapsulated PSC efficiencies.…”

“…[46] There are only a few works to report PSC stability improvements using ALD-coated Al 2 O 3 [46,[57][58][59][60][61] and the main drawbacks lie in the usual aggressive deposition conditions (mostly, the high temperature range typically applied in many ALD protocols, usually from 80 to 300 C) that can stress and degrade the perovskite underlayer, decreasing the initial preencapsulated PSC efficiencies. For example, ALD deposition of Al 2 O 3 on MAPbI 3 PSCs usually requires mild conditions (60 C) to reach stability with no costs to efficiency, [46,61] yet to date there are no examples of ALD-Al 2 O 3 encapsulation for efficient and stable MAPbI 3 -based p-i-n PSCs in which the perovskite is processed by coevaporation.…”

“…[46,55] The use of ALD for encapsulation is particularly interesting for PSCs to diminish the perovskite toxicity effects and their quick degradation in air, as reviewed by Zardetto et al [56] Among the many oxides obtainable by ALD, Al 2 O 3 is a versatile material that can be ALD-grown from trimethylaluminum (TMA) and water (or ozone) as precursors on top of different materials with all types of hydrophilicity and has a very-low water vapor transmission rate of 10 À6 g m À2 per day. [46] There are only a few works to report PSC stability improvements using ALD-coated Al 2 O 3 [46,[57][58][59][60][61] and the main drawbacks lie in the usual aggressive deposition conditions (mostly, the high temperature range typically applied in many ALD protocols, usually from 80 to 300 C) that can stress and degrade the perovskite underlayer, decreasing the initial preencapsulated PSC efficiencies. For example, ALD deposition of Al 2 O 3 on MAPbI 3 PSCs usually requires mild conditions (60 C) to reach stability with no costs to efficiency, [46,61] yet to date there are no examples of ALD-Al 2 O 3 encapsulation for efficient and stable MAPbI 3 -based p-i-n PSCs in which the perovskite is processed by coevaporation.…”