Vitrification Transformation of Poly(Ethylene Oxide) Activating Interface Passivation for High‐Efficiency Perovskite Solar Cells

Abstract

Interface engineering is critical for achieving high-efficiency and high-stability perovskite solar cells (PSCs). Herein, a new interface engineering approachpoly(ethylene oxide) (PEO) modification of SnO 2 quantum dot (QD) film-to improve electron transport is introduced. It is found that when the PEO film is annealed over its glass-transition temperature, the ether-oxygen unshared electron pair in the PEO film activates to form a crosslinking complex with metal ions at the SnO 2 QD and perovskite interface, which triggers heterogeneous nucleation over the perovskite precursor film and is beneficial for achieving uniform and dense perovskite films. PEO is also shown to passivate the bulk defects of perovskite films and the interface defects between SnO 2 QD and perovskite, which promotes electron-transferring from the perovskite layer to cathode. PSCs based on SnO 2 QD with PEO treatment exhibit an enhanced efficiency, leading to a champion PCE of 20.23%, with good reproducibility and stability.

Tin Oxide Electron‐Selective Layers for Efficient, Stable, and Scalable Perovskite Solar Cells

“…Image for “Poly(ethylene oxide)”: Reproduced with permission. [ 268 ] Copyright 2019, Wiley‐VCH. Image for “Red‐carbon quantum dots”: Reproduced with permission.…”

“…Next, poly(ethylene oxide) (PEO, also known as poly(ethylene glycol); (PEG) was used to form a crosslinking complex between the perovskite and metal ions in SnO 2 , thereby providing bulk passivation of the perovskite and surface passivation of the SnO 2 film. [266,268] Moreover, PEG incorporation enhances the surface wettability of SnO 2 , which benefits the deposition of uniform and pinhole-free perovskites onto SnO 2 . Overall, although many successful polymers have been reported with enhanced V OC , the insulating nature of the polymers mostly causes FF losses due to the increased contact resistivity.…”

“…Copyright 2019, Wiley-VCH. Image for "Poly(ethylene oxide)": Reproduced with permission [268]. Copyright 2019, Wiley-VCH.…”

Diethylammonium Iodide Assisted Grain Growth with Sub‐Grain Cluster to Passivate Grain Boundary for CH3NH3PbI3 Perovskite Solar Cells

“…The SnO 2 QD film serves as an electron transport layer. [ 8,9 ] The fabrication of the perovskite films uses a one‐step antisolvent dripping method described in literature, [ 25 ] as is shown in Figure 1c. Note that 150 μL DAI CB solution with the concentration of 0.5 mg mL −1 is drop‐casted rapidly on the spinning film at 10 s before the end of this program (shown in Figure 1b).…”

“…[ 6 ] Recently, different passivation strategies have concentrated prevailingly on interface and additive engineering. [ 3,7–9 ] The doping and modification with additive can affect the crystallization, thereby passivate the defects in the bulk or at GBs/surface of perovskite. [ 10 ] At present, inert molecules, [ 11 ] small molecules, [ 12,13 ] carbon nanotubes, [ 14 ] graphene‐quantum‐dots, [ 15 ] core–shell nanomaterials, [ 16 ] and polymers [ 17 ] have been used to passivate the interface defect of perovskite films.…”