Abstract Formamidinium lead iodide (FAPbI 3 ) and SnO 2 are a promising pair of halide perovskite and electron transport layer (ETL). However, FAPbI 3 and SnO 2 have inherent problems such as high crystallization temperature of FAPbI 3 and surface defects of SnO 2 like oxygen vacancies. They cause low crystallinity, non‐uniform grain growth, and more interface defects, leading to carrier recombination and leakage current. The passivation of the interface between FAPbI 3 and SnO 2 is an effective process to address these materials issues. Herein, a dual role of lead sulfide (PbS) quantum dots (QDs) in the interface passivation is explored. PbS QDs which are introduced to the interface between FAPbI 3 and ETL, link to Sn‐dangling bonds of SnO 2 ETLs and anchor the iodine atoms of FAPbI 3 . This changes considerably lower nonradiative recombination, achieve a better energetic alignment between ETL and PbI 3 , and facilitate electron extraction, leading to a power conversion efficiency of 21.66%. image

In this work, the ability of reducing reaction byproduct from chemical vapor deposition of SiON thin film is explored changing balance gas, time and power within the wafer discharging process. In order to control the surface remaining NH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf><sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>byproduct, which is reported to induce profile deviation in photolithography patterning, post N2O plasma treatment has been widely used. However, the N2O plasma treatment has inherent limitation of utilizing greenhouse gas and imperfect removal efficiency. Although N2 is generally considered to be inert due to the stable triple N-N bond, based on the material screening and DFT calculation, we newly postulated that N* radical from N2 plasma may reduce NH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf><sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>ions more efficiently compared with O* radical from N2O plasma, possibly by the more favored H<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>dissociation reaction between NH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf><sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> and NH3 (-32.6 eV for N* radical driven pathway / −21.9 eV for O* radical driven pathway). Indeed, by using slight plasma power generated during the wafer discharging stage and changing balance gas from N2O to N2, the surface remaining NH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf><sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>ion was removed by almost 100% confirmed by High Performance Ion Chromatography (HPIC). Additionally, critical dimension uniformity of EUV patterning was also improved by 0.03nm in ADI and 0.11nm in ACI states, respectively. We believe that our finding exploits new strategy for controlling surface condition of hard mask with more simplified and sustainable method.