Tuning the Amount of Oxygen Vacancies in Sputter‐Deposited SnO_x films for Enhancing the Performance of Perovskite Solar Cells

Abstract

This work demonstrates the effect of oxygen vacancies in SnO thin films on the performance of perovskite solar cells. Various SnO films with different amounts of oxygen vacancies were deposited by sputtering at different substrate temperatures (25-300 °C). The transmittance of the films decreased from 82 to 66 % with increasing deposition temperature from 25 to 300 °C. Both X-ray photoelectron spectroscopy and electron-spin resonance spectroscopy confirmed that a higher density of oxygen vacancies was created within the SnO film at a high substrate temperature, which caused narrowing of the SnO bandgap from 4.1 (25 °C) to 3.74 eV (250 °C). Combined ultraviolet photoelectron spectroscopy and UV/Vis spectroscopy showed an excellent conduction band position alignment between the methylammonium lead iodide perovskite layer (3.90 eV) and the SnO electron transport layer deposited at 250 °C (3.92 eV). As a result, a significant enhancement of the open-circuit voltage from 0.82 to 1.0 V was achieved, resulting in an increase of the power conversion efficiency of the perovskite solar cells from 11 to 14 %. This research demonstrated a facile approach for controlling the amount of oxygen vacancies in SnO thin films to achieve a desirable energy alignment with the perovskite absorber layer for enhanced device performance.

Applications of Self‐Assembled Monolayers for Perovskite Solar Cells Interface Engineering to Address Efficiency and Stability

“…[70] The charge transport layers (CTLs) commonly used for perovskite solar cells are metal oxides, such as TiO 2 , SnO 2 , ZnO, NiO, WO 3−x , MoO x , etc., or organic [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) and poly(3,4-ethylenedioxythiophene) polystyrene (PEDOT:PSS). [45,[71][72][73][74] These CTLs have hydroxyl groups at the surface which chemically react with carboxyl, sulfonic, phosphonic, or silane anchoring groups of the SAMs. [75] After such interaction, the anchoring groups form a dipole moment at the interface affecting the energy level and changing the WF [76] at the surface, facilitating the charge collection.…”

Scalable Fabrication of Stable High Efficiency Perovskite Solar Cells and Modules Utilizing Room Temperature Sputtered SnO2 Electron Transport Layer

“…Among these different types of technology, sputtering deposition is promising for large scale, low‐cost, and uniform deposition with the use of low‐cost SnO 2 target. To date there are only two reports using sputtering of SnO 2 for perovskite solar cells, but the reported efficiency is only 14% for an area of 0.09 cm 2 due to the unoptimized structure . Besides the better uniformity across large area achieved by sputtering deposition, the higher conductivity of SnO 2 compared with TiO 2 can also help improve the interconnection between sub‐cells in PSMs.…”

Strategically Constructed Bilayer Tin (IV) Oxide as Electron Transport Layer Boosts Performance and Reduces Hysteresis in Perovskite Solar Cells

“…In contrast SnO 2 , deposited as a dense compact layer of nanostructured particles, has recently emerged as a n‐type layer for PSCs, with advantages of high optical transparency, high electron mobility, UV‐stabled properties as well as low‐temperature processing . A number of diverse preparation methods for compact SnO 2 layers have been reported . Fang and co‐workers used SnCl 2 ·2H 2 O as precursor to process SnO 2 as the ETL in PSCs showing a PCE over 17%, albeit with pronounced hysteresis .…”