Ultra‐Thin Atomic Layer Deposited–Nb₂O₅ as Electron Transport Layer for Co‐Evaporated MAPbI₃ Planar Perovskite Solar Cells

Abstract

Herein, the performance of atomic layer deposited (ALD)‐Nb2O5 is compared with existing standard electron transport layer (ETL) configuration in planar n‐i‐p perovskite solar cell architectures. By making use of a co‐evaporated perovskite absorber layer, electron transport materials, such as phenyl‐C61‐butyric acid methyl ester (PCBM), TiO2, and Nb2O5, are compared in stand‐alone and bilayer configurations. The device performance in terms of hysteresis, scan rate dependency, and stability is associated with ETL–perovskite interactions and ALD‐Nb2O5 fabricated using a PCBM interfacial layer exhibits superior behavior on all fronts. Using an atomic layer deposition technique can drastically reduce the process temperatures, resulting in conformal Nb2O5 suitable for evaporated perovskite absorbers with promise toward using them in flexible applications.

Dynamic synergy of tin in the electron-transfer layer and absorber layer for advancing perovskite solar cells: a comprehensive review

“…This makes ALD a prevalent choice for producing ultrathin, top-notch SnO 2 films tailored for applications as ETL materials. [115][116][117][118] Lu et al 119 explored the microstructural aspects of epitaxial thin layers of SnO 2 grown on a-Al 2 O 3 (012) substrates at a temperature of 600 1C. This could be accomplished using SnCl 4 or SnI 4 as the Sn source in an ALD set-up.…”

“…This makes ALD a prevalent choice for producing ultrathin, top-notch SnO 2 films tailored for applications as ETL materials. 115–118…”

The J–V Hysteresis Behavior and Solutions in Perovskite Solar Cells

“…The ETL with bilayer structure (bi‐ETL) has been extensively studied due to its excellent electron transport and stability. [ 197 ] Using bi‐ETL in PSCs can not only improve PCE but also reduce the level of hysteresis, such as PC 61 BM/C 60 , [ 54 ] PC 61 BM/AZO (Al‐doped ZnO), [ 198 ] barium hydroxide/boron‐doped ZnO, [ 199 ] Nb 2 O 5 /PC 61 BM, [ 200 ] C 60 /ultrathin‐TiO x , [ 201 ] and bilayer SnO 2 . [ 23 ] The bilayer SnO 2 (a layer of colloidal SnO 2 spin‐coated on the sol–gel SnO 2 ) as the ETL has better energy level alignment with the perovskite and accelerates the charge extraction.…”

Recoverable Flexible Perovskite Solar Cells for Next‐Generation Portable Power Sources

“…[103] In addition to the above typical oxide materials, there are some metal oxides that have also been investigated by researchers, for example: Shin et al used ZSO nanoparticles (with an average size of 19.2 nm) and ZSO quantum dots (with an average size of 5.7 nm) as two-ETLs in FPSCs, which significantly inhibited recombination of photogenerated charges, and obtained a PCE of 16 % (Figure 3b). [104] In 2019, Subbiah et al used atomic-layer-deposited Nb 2 O 5 as the interface layer between the PCBM and perovskite layers, and the study found that Nb 2 O 5 could prevent charge accumulation at the interface and significantly reduce the hysteresis effect of the device; [105] and our group fabricated FPSCs by using Nb 2 O 5 as the ETL, leading to a FPSC with a PCE of 18.4 % with good device stability and recoverability (Figure 3f). [106] The application of other metal oxides as electrode materials in FPSCs is limited and needs to be explored and studied continuously.…”