Figure 1. Theoretical insights into inhibition mechanisms of mobile Li+ ions. (a) ESP images of TCB, OA, and TCPO. Molecular structures (b) and binding energies (c) of Li+ with TCB, OA, and TCPO calculated and optimized using density functional theory. (d) Design thought of TCPO ligand molecules used for host-guest complexation interaction.
Figure 2. Promoted p-doping by TCPO and chemical interaction of TCPO with Li+ ion. (a) ESR spectra of Spiro, Spiro-TCPO, Spiro-Li, and Spiro-Li-TCPO solutions. (b) UV-visible absorption spectra of Spiro, Spiro-TCPO, Spiro-Li and Spiro-Li-TCPO films. (c) Cyclic voltammograms of Spiro, Spiro-TCPO, Spiro-Li, and Spiro-Li-TCPO. (d) FTIR spectra of Li-TFSI, TCPO and TCPO-Li-TFSI in the wavenumber range of 1600-2000 cm-1. (e)7Li NMR of Li-TFSI solutions with and without TCPO. (f) 13C NMR of TCPO solutions with and without Li-TFSI. (g) Schematic illustration of the mechanisms of p-doping promotion and Li+ migration suppression via TCPO.
Figure 3. Characterization of HTLs without and with TCPO. AFM (a) and c-AFM (b) images of pure Spiro, Spiro-TCPO, Spiro-Li, and Spiro-Li-TCPO. The size of the images is 2×2 μm2. Conductivities (c) and hole mobilities (d) of pure Spiro, Spiro-TCPO, Spiro-Li, and Spiro-Li-TCPO. PL (e) and TRPL (f) spectra of perovskite films coated with Spiro-Li and Spiro-Li-TCPO films on glass substrates. PVSK stands for perovskite. (g) Energy level arrangement of Spiro-Li films with and without TCPO.
Figure 4. Simultaneous suppression of Li+, I- and Ag migration via host-guest complexation. (a) Photographs of the perovskite films with Spiro-Li (control) and Spiro-Li-TCPO (target) under damp and heat environment (temperature 85 ℃, relative humidity 61%) after aging for 1, 2, 4, 6 and 8 days. (b) Water contact angles of the perovskite films with Spiro-Li and Spiro-Li-TCPO. (c) Cross-sectional SEM images of the perovskite films with Spiro-Li and Spiro-Li-TCPO under damp and heat environment (temperature 85 ℃, relative humidity 61%) before and after aging for 8 days. (d) TOF-SIMS for the control and target devices after exposing to one sun and heating at 65 °C for 8 days. (e) TOF-SIMS 3D reconstruction of CsAg+, Cs2I-and Li+ ions. (f) Schematic diagram of suppressing I-, Li+, and Ag migration through TCPO.
Figure 5. Photovoltaic performance and long-term stability of devices without and with TCPO. (a) J-V curves of the best-performing devices without and with TCPO. (b) J-V curves of the champion control and target devices with an active area of 1 cm2. (c) J-V curves of the best-performing devices without and with TCPO prepared using a two-step perovskite deposition approach (active area 0.08 cm2). (d) Comparison of the PCEs for our device and reported highly efficient n-i-p structure PSCs. TPC (e) and TPV (f) curves for the control and target devices. (g) Humidity stability of the control and modified PSCs in a light-shielded environment at 25-35% relative humidity. (h) Operation stability of the unencapsulated control and target devices at MPP under continuous 1 sun irradiation. (i) Thermal stability of the unencapsulated control and modified devices heated at 65 °C in a dark nitrogen glove box.
Qian Zhou#, Yingying Yang#, Dongmei He*, Ke Yang, Yue Yu, Xinxing Liu, Jiajia Zhang*, Xuxia Shai, Jinsong Wang, Jianhong Yi, Meicheng Li*, Jiangzhao Chen*. Simultaneous suppression of multilayer ion migration via molecular complexation strategy toward high-performance regular perovskite solar cells. Angew. Chem. Int. Ed. 2024, e202416605.
https://onlinelibrary.wiley.com/doi/10.1002/anie.202416605
