So far, most techniques for modifying perovskite solar cells (PSCs) focus on either the perovskite or electron transport layer (ETL). For the sake of comprehensively improving device performance, a dual‐functional method of simultaneously passivating trap defects in both the perovskite and ETL films is proposed that utilizes guidable transfer of Eu3+ in SnO2 to perovskite. Europium ions are distributed throughout the SnO2 film during the formation process of SnO2, and they can diffuse directionally through the SnO2/perovskite interface into the perovskite, while most of the europium ions remain at the interface. Under the synergistic effect of distributed Eu3+ in the SnO2 and aggregated Eu3+ at the interface, the electron mobilities of ETLs are evidently improved. Meanwhile, diffused Eu3+ ions passivate the perovskite to reduce trap densities at the grain boundaries, which can dramatically elevate the open‐circuit voltage (Voc) of PSCs. Finally, the mainly PSCs coated on SnO2:Eu3+ ETL achieve a power conversion efficiency of 20.14%. Moreover, an unsealed device degrades by only 13% after exposure to ambient atmosphere for 84 days.

Minimizing surface defect is vital to further improve power conversion efficiency (PCE) and stability of inorganic perovskite solar cells (PSCs). Herein, we designed a passivator trifluoroacetamidine (TFA) to suppress CsPbI 3À x Br x film defects. The amidine group of TFA can strongly chelate onto the perovskite surface to suppress the iodide vacancy, strengthened by additional hydrogen bonds. Moreover, three fluorine atoms allow strong intermolecular connection via intermolecular hydrogen bonds, thus constructing a robust shield against moisture. The TFA-treated PSCs exhibit remarkably suppressed recombination, yielding the record PCEs of 21.35 % and 17.21 % for 0.09 cm 2 and 1.0 cm 2 device areas, both of which are the highest for allinorganic PSCs so far. The device also achieves a PCE of 39.78 % under indoor illumination, the highest for allinorganic indoor photovoltaic devices. Furthermore, TFA greatly improves device ambient stability by preserving 93 % of the initial PCE after 960 h.

commercialization due to ever-increasing power conversion efficiency (PCE), which has soared to 25.7% as of 2022. [1][2][3][4] Nonetheless, the inadequate stability caused by thermal degradation of hybrid perovskite still poses a great challenge for commercialization. [5] To circumvent this concern, all-inorganic cesium lead halide perovskites (CsPbX 3 , X = Br, I), whose volatile and vulnerable organic parts can be replaced by stable inorganic Cs + , have attracted considerable attention and exhibited great potential for both high-performance single-junction and top cells in tandem soar cells due to their unparalleled stability at high temperature. [6][7][8] In recent years, thanks to a lot of research work and incisive investigation, cesium-based inorganic perovskites have made remarkable progress in reducing the defect densities and stabilizing the black phase in the perovskite films, due especially to precursor solution optimization, [9][10][11][12] compositional engineering, [13][14][15] interface modification [16][17][18][19] and strain engineering. [6,20] Despite these unremitting efforts, the current record PCE is considerably lower than that of its hybrid counterpart and the Shockley-Queisser (S-Q) limit (≈30%). [21] This shortcoming is ascribed to a large energy loss (E loss ), suggesting that severe Shockley-Read-Hall recombination occurs in the interface or absorber layer in these solar cells, which is mainly attributed to the inevitable formation of a large number of shallow-or deeplevel defects in the crystal growth of CsPbI 3−x Br x film. [21][22][23] These undesirable defects, especially deep-level defects, are considered as nonradiative recombination centers and active sites for water adsorption. As a result, they tend to cause inferior device performance and long-term instability. [24] Thus, it is of great significance to prepare superior perovskite films with low-defect density for obtaining high-efficiency solar cells.Recently, intensive research on the deep-level physical mechanism of inorganic perovskite has led to improvements of the efficiency and stability of inorganic perovskite devices. [25][26][27][28] Lou et al. demonstrated the there are many point defects in inorganic perovskite, such as the Cs + vacancy (V Cs ) and undercoordinated Pb 2+ , etc. These inevitable defects can impair the interaction between Cs + and [PbI 6 ] 4− octahedra to some extent, thus reducing the energy difference between the black phase and yellow phase. [24,25] According to density functional theoryThe nonradiative charge recombination caused by surface defects and inferior crystalline quality are major roadblocks to further enhancing the performance of CsPbI 3−x Br x perovskite solar cells (PSCs). Theoretical calculations indicate that sodium diethyldithiocarbamate (NaDDTC), a popular bacteriostatic benign material, can initiate multiple interactions with the CsPbI 3−x Br x perovskite surface to effectively passivate the defects. The experimental results reveal that the NaDDTC can indeed passivate the elect...

Minimizing surface defect is vital to further improve power conversion efficiency (PCE) and stability of inorganic perovskite solar cells (PSCs). Herein, we designed a passivator trifluoroacetamidine (TFA) to suppress CsPbI3−xBrx film defects. The amidine group of TFA can strongly chelate onto the perovskite surface to suppress the iodide vacancy, strengthened by additional hydrogen bonds. Moreover, three fluorine atoms allow strong intermolecular connection via intermolecular hydrogen bonds, thus constructing a robust shield against moisture. The TFA‐treated PSCs exhibit remarkably suppressed recombination, yielding the record PCEs of 21.35 % and 17.21 % for 0.09 cm2 and 1.0 cm2 device areas, both of which are the highest for all‐inorganic PSCs so far. The device also achieves a PCE of 39.78 % under indoor illumination, the highest for all‐inorganic indoor photovoltaic devices. Furthermore, TFA greatly improves device ambient stability by preserving 93 % of the initial PCE after 960 h.

No abstract