陈江照&臧志刚Nano-Micro Letters：通过氟和磺酸基团协同稳定埋底界面得到基于两步法超24%效率的钙钛矿电池

界面缺陷和界面能带匹配不理想是导致界面非辐射复合的主要原因。此外，碘化铅薄膜和钙钛矿薄膜结晶差限制了使用两步法制备器件的光伏性能进一步提高。鉴于此，重庆大学陈江照研究员以及臧志刚教授等人报道了一种基于氟(F)和磺酰基(S=O)官能团协同作用的埋界面稳定策略。

氟(F)和磺酰基(S=O)官能团能够与钙钛矿组分实现氢键、配位键、离子键等多种化学键，增强了界面接触和缺陷钝化效果。改性分子与钙钛矿以及SnO2之间的化学相互作用随着S=O和F数目的增加而不断增强。缺陷钝化效果与化学相互作用强度呈正相关。钙钛矿结晶动力学是通过化学相互作用强度和基底的润湿性之间的均衡来调节的。与Cl-相比，所有非卤素阴离子在结晶优化、能带调节和缺陷钝化方面表现更好。

建立了分子结构、缺陷钝化、界面能带排列、钙钛矿结晶与器件性能之间的相关性。KFSI改性的器件达到了24.17%的效率。

Fig. 1aMolecular structures of potassium salts used for modifying buried interface and schematic illustration of the interaction of modifiers and functional layers.bSn 3d andcO 1s XPS spectra of the control and modified SnO2 layers.dFTIR spectra of pure KMS, KTFSI and KFSI and the SnO2films without and with KMS, KTFSI and KFSI.eXPS spectra of the control and modified perovskite films.fFTIR spectra of the PbI2films with or without KMS, KTFSI and KFSI. XRD patterns of thegPbI2 films andhperovskite films deposited on SnO2ETLs without or with KCl, KMS, KTFSI and KFSI.

Fig. 2a,bTop-view andccross-sectional SEM images of the control and modified perovskite films.

Fig. 3aUV-vis absorption spectra of the perovskite films with or without modifiers.b,dSSPL andc,eTRPL spectra of the perovskite films prepared on non-conductive glass without and with modifiers by measuring from theb,cglass side ord, eperovskite side.fPL mapping images of the perovskite films deposited on non-conductive glass without and with modifiersgDark I–V curves of the electron-only devices.

Fig. 4aSSPL andbTRPL spectra of the perovskite films deposited on SnO2 films without and with modifiers. PL mapping images of the perovskite films prepared on thecbare SnO2 and SnO2 modified bydKCl,eKMS,fKFSI andgKTFSI.hMott–Schottky analysis,iVOC as a function of light intensities for the control and modified PSCs,jTPC andkTPVlNyquist plots of the control and modified devices measured at a bias of 0.8 V in the frequency range of 1 MHz to 0.01 Hz in the dark. An enlarged view of the high-frequency region is shown in the inset.

Fig. 5aStatistical distribution of the PCEs of the PSCs based on the SnO2 films without and with KCl, KMS, KTFSI and KFSI. The statistical data were obtained from 20 individual cells for each kind of device.bJ–Vcurves andcEQE spectra of the best-performing devices based on bare SnO2 film and KCl, KMS, KTFSI and KFSI modified SnO2 films. J–Vcurves were measured under simulated AM 1.5G one sun illumination of 100 mW/cm2.dSteady-state current density andePCE versus time for the best-performing devices employing pristine and modified SnO2 films measured at the maximum power point.fJ-V curves of the KFSI-modified champion PSCs with PEAI posttreatment. PCE evolution of the unencapsulated control and modifiedgunder 25%-30% relative humidity at room temperature in the dark,hat 60 ℃ in the dark in the nitrogen-filled glovebox. Error bars represent the standard deviation of five devices.

参考文献

Cheng Gong, Haiyun Li, Cong Zhang, Qixin Zhuang, Zhiyuan Xu, Huaxin Wang, Ru Li, Hua Yang, Jiangzhao Chen,* and Zhigang Zang*. Stabilizing buried interface via synergistic effect of fluorine and sulfonyl functional groups toward efficient and stable perovskite solar cells. Nano-Micro Letters.15,1 (2022).

https://doi.org/10.1007/s40820-022-00992-5

https://link.springer.com/10.1007/s40820-022-00992-5

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