Yi Zhou

The –CF₃ group in EMTC forms H-bonds with FA⁺, anchoring it and suppressing ion migration. Meanwhile, CO, S, and –CF₃ coordinate with undercoordinated Pb²⁺, passivating defects, promoting larger grains, stabilizing [PbI₆]⁴⁻, and reducing organic cation volatilization.

Dicyandiamide (DCD) was used to modify SnO₂, with –CN passivating defects and –NH₂ improving perovskite crystallization. This improved energy alignment and film quality, increasing PCE from 21.28% to 24.50% and enhancing stability.

Chlorinated-Ti₃C₂T_F is used as dual functional buried-interface on SnO₂ electron transporting layer for 25.09% high performance n–i–p perovskite solar cells.

All-inorganic perovskite CsPbI₃ is widely recognized as a promising material for photovoltaic applications in single-junction or tandem solar cells. However, the spontaneous phase transition of CsPbI₃ remains a crucial obstacle to commercialization. In this study, we propose a surface engineering approach using a tetra-n-butylammonium hexafluorophosphate (TBAPF₆) ionic liquid to prevent the perovskite-to-non-perovskite phase transition induced by moisture. The experimental results demonstrate that by chemically bonding excess lead iodide (PbI₂) with a tetrabutylammonium cation (TBA⁺), a low-dimensional stable and hydrophobic material called [TBA]PbI₃ was achieved, which effectively enhances the stability of the CsPbI₃ perovskite structure. Furthermore, we found that the hexafluorophosphate anion (PF₆ ⁻) can effectively passivate surface iodine vacancies and interact with uncoordinated Pb²⁺. Consequently, the CsPbI₃-based perovskite solar cells (C-PSCs) employing the TBAPF₆ treatment achieved an impressive power conversion efficiency (PCE) of 17.47%. Moreover, the unencapsulated devices retained more than 70% of their initial PCE after being stored in ambient air for 168 hours.

Nucleus epitaxial growth is employed to fabricate perovskite films with high quality by introducing δ-FAPbI₃ into the precursor. This strategy delivers an efficient and stable perovskite solar cell.

All‐inorganic perovskite CsPbI₃ contains no volatile organic components and is a thermally stable photoactive material for wide‐bandgap perovskite solar cells (PSCs); however, CsPbI₃ readily undergoes undesirable phase transitions due to the hygroscopic nature of the ionic dopants used in commonly used hole transport materials. In the current study, the popular donor material PM6 in organic solar cells is used as a hole transport layer (HTL). The benzodithiophene‐based backbone‐conjugated polymer requires no dopant and leads to a higher power conversion efficiency (PCE) than 2,2′,7,7′‐tetrakis[N,N‐di(4‐methoxyphenyl)amino]‐9,9′‐spirobifluorene (Spiro‐OMeTAD). Moreover, PM6 also shows priorities in hole mobility, hydrophobicity, cascade energy level alignment, and even defect passivation of perovskite films. With PM6 as the dopant‐free HTL, the PSCs achieve a champion PCE of 18.27% with a competitive fill factor of 82.8%. Notably, the present PCE is based on the dopant‐free HTL in CsPbI₃ PSCs reported thus far. The PSCs with PM6 as the HTL retain over 90% of the initial PCE stored in a glovebox filled with N₂ for 3000 h. In contrast, the PSCs with Spiro‐OMeTAD as the HTL maintain ≈80% of the initial PCE under the same conditions.

The defects at the surface and grain boundary of perovskite films are detrimental to constructing highly stable and efficient perovskite solar cells (Pero-SCs). Here, we propose a facile additive-associated antisolvent engineering (AAE) method to acquire high-quality perovskite films. The additives and antisolvent adopt in the current study are zwitterionic taurine and chlorobenzene. It has been proven that the AAE method can slow down the nucleation process during thermal annealing and consequently passivate the defects of perovskite films via coordination and hydrogen bonding. After being treated with AAE, the champion power conversion efficiency of p–i–n Pero-SCs based on Cs_0.05(FA_0.92MA_0.08)_0.95Pb(I_0.92Br_0.08)₃ is improved from 19.73% to 22.54%. Concomitantly, the device stability is also improved. Being stored in a glovebox filled with N₂, the unencapsulated Pero-SCs treated with AAE maintain 80% and 94% of the initial PCEs in 2500 h at 70 °C and in 3200 h at room temperature, respectively.

Defects at the grain boundaries and surfaces of perovskite thin films are the key factors that cause nonradiative recombination, thus restricting the performance of perovskite solar cells (Pero-SCs). By introducing foreign additives to manage the chemical environment of the precursor, perovskite films can obtain optimized morphology and reduced defects, thereby enhancing the photovoltaic performance and stability of derived Pero-SCs. Herein, we report the bifunctional molecule metformin hydrochloride (MetHCl), whose multidentate structure is capable of simultaneously passivating several sorts of defects in perovskite films. Concurrently, the strong binding ability to Pb²⁺ makes it impressive in regulating perovskite crystallization. The nonvolatile MetHCl can remain in the perovskite film, contributing to acquiring a high-quality film with denser grains and fewer pinholes. Finally, p-i-n Pero-SCs containing the MetHCl additive exhibited enhanced stability and achieved a champion power conversion efficiency of 21.59% with an open-circuit voltage of 1.17 V.