化学浴沉积法（CBD）是一种制备高质量SnO2的有效方法，但由于Sn2+向Sn4+的不完全转移以及CBD-SnO2表面羟基的存在，导致氧空位的存在，严重影响了电池的效率和稳定性。华北电力大学李美成团队在CBD过程中引入氯化铕六水合物，Eu3+促进了Sn4+的形成，降低了SnO2/钙钛矿界面的陷阱态，优化了SnO2/钙钛矿界面的能级排列，促进了界面的电荷转移，最后，基于Eu-SnO2 ETL的PSC的光电转换效率从22.02%显著提高到24.50%。该器件还保持了良好的稳定性，在环境空气中1464小时后仍保持其初始效率的97%。这种方法为进一步改善SnO的膜质量及其与钙钛矿的接触提供了一种有前途的策略，显示出高效和稳定的PSC的巨大潜力。该篇文章被Sustainable Energy & Fuels 收录为热点文章！
Fig. 1 Characterization of SnO2 films. XPS spectra of SnO2 and Eu-SnO2: (a) Eu 3d, (b) Eu 4d, (c) Sn 3d, (d) O1s and (e) Cl 2p. (f) J-V curves of simi-devices with the structure FTO/SnO2(or Eu-SnO2)/Au. (g) Electron mobility characterization of electron-only semi-devices with the structure FTO/SnO2(or Eu-SnO2)/PCBM/Au. (h) UPS spectra and (f) Energy level diagram of ETL and perovskite films.
Fig. 2 (a) Top-view and (b) cross-sectional SEM images of SnO2 film. (c) Top-view and (d) cross-sectional of Eu-SnO2 film. (e, f) Surface roughness of SnO2 and Eu-SnO2 films. (g, h) Contact angles of PbI2 solutions on SnO2 and Eu-SnO2 films. (i) GIXRD patterns of SnO2 films with and without EuCl3·6H2O
Fig. 3. (a) Top-view and (b) cross-sectional images of the perovskite film deposited on SnO2 ETL. (c) Top-view and (d) cross-sectional images of perovskite film deposited on Eu-SnO2 ETL. The scale bar is 1 μm. (e) XRD and (f) UV-vis spectra of perovskite films deposited on different ETL films. (g) Dark J-V curves of electron-only semi-devices with the structure FTO/ETL/perovskite/PCBM/Au. (h) SSPL spectra and (i) TRPL spectra of perovskite films deposited on different ETL substrates.
Fig. 4 (a) J-V curves of PSCs treated with different concentrations of EuCl3·6H2O. Statistical (b) PCE and (c) FF of PSCs with different ETLs, including 7 SnO2 samples and 11 Eu-SnO2 samples. (d) Best-performing J-V curves of PSCs with different ETLs with an active area of 0.1 cm2. (e) J-V curves of PSCs scanned at forward and reverse direction. (f) EQE and (g) EIS spectra of PSCs with different ETLs. (h) Air-stability measurement of the PSCs stored in a drying closet with a humidity of 10±5%. (i) J-V curves of PSCs with different ETLs before and after aging.
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