Superfast Room‐Temperature Activation of SnO₂ Thin Films via Atmospheric Plasma Oxidation and their Application in Planar Perovskite Photovoltaics

Abstract

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has now exceeded 20%; thus, research focus has shifted to establishing the foundations for commercialization. One of the pivotal themes is to curtail the overall fabrication time, to reduce unit cost, and mass-produce PSCs. Additionally, energy dissipation during the thermal annealing (TA) stage must be minimized by realizing a genuine low-temperature (LT) process. Here, tin oxide (SnO ) thin films (TFs) are formulated at extremely high speed, within 5 min, under an almost room-temperature environment (<50 °C), using atmospheric Ar/O plasma energy (P-SnO ) and are applied as an electron transport layer of a "n-i-p"-type planar PSC. Compared with a thermally annealed SnO TF (T-SnO ), the P-SnO TF yields a more even surface but also outstanding electrical conductivity with higher electron mobility and a lower number of charge trap sites, consequently achieving a superior PCE of 19.56% in P-SnO -based PSCs. These findings motivate the use of a plasma strategy to fabricate various metal oxide TFs using the sol-gel route.

Efficient Mixed‐Cation Mixed‐Halide Perovskite Solar Cells by All‐Vacuum Sequential Deposition Using Metal Oxide Electron Transport Layer

“…All XRD peaks for SnO 2 were indexable to the tetragonal SnO 2 structure, indicating the formation of pure SnO 2 crystals. In addition, the sputtered SnO 2 film on FTO glass showed high transmittance close to 90% in the visible region (Figure d), which is slightly higher than the high‐temperature‐processed spin‐coated SnO 2 film . These measurements convince that the room‐temperature‐sputtered SnO 2 has desirable properties as an effective ETL.…”

Composition and Energy Band–Modified Commercial FTO Substrate for In Situ Formed Highly Efficient Electron Transport Layer in Planar Perovskite Solar Cells

“…In addition, all the O 1s peaks are deconvolved into two individual peaks which originate from the fully coordinated lattice oxygen atoms (O L , 530.2 eV) and the hydroxide species (O H , 531.2 eV) . The hydroxide species is born of incomplete oxidation and high fluorine doping ratio . Hydroxide species would bring about shallow trap sites and thus decrease the mobility of SnO 2 and hinder the electron transport With increasing the treatment power, more hydroxide oxygen species turn into lattice oxygen which further confirms the formation of SnO 2 phase.…”

Tungsten-Doped Zinc Oxide and Indium–Zinc Oxide Films as High-Performance Electron-Transport Layers in N–I–P Perovskite Solar Cells

“…Currently, the most commonly used oxides include TiO 2 [2,15], ZnO [16] although a variety of other metal oxides [17,18], such as Nb 2 O 5 [19] and SnO 2 [20,21], may also be used, allowing some control of the interfacial properties and variability in junctions formed between electrodes and the CH 3 NH 3 PbI 3 layer. Recently, reports of new metal oxide-based PSCs have demonstrated that PCEs in the range of 15~20% are possible via development and optimization of new oxide layers [22][23][24][25][26][27][28][29][30]. These inorganic oxides are considered excellent interfacial materials due to their superior stability and electrical properties.…”