Long-term durability is critically important for the commercialization of perovskite solar cells (PSCs). The ionic character of the perovskite and the hydrophilicity of commonly used additives for the hole-transporting layer (HTL), such as lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) and tertbutylpyridine (tBP), render PSCs prone to moisture attack, compromising their long-term stability. Here we introduce a trifluoromethylation strategy to overcome this drawback and to boost the PSC's solar to electric power conversion efficiency (PCE). We employ 4-(trifluoromethyl)benzylammonium iodide (TFMBAI) as an amphiphilic modifier for interfacial defect mitigation and 4-(trifluoromethyl)pyridine (TFP) as an additive to enhance the HTL's hydrophobicity. Surface treatment of the triple-cation perovskite with TFMBAI largely suppressed the nonradiative charge carrier recombination, boosting the PCE from 20.9% to 23.9% and suppressing hysteresis, while adding TFP to the HTL enhanced the PCS's resistance to moisture while maintaining its high PCE. Taking advantage of the synergistic effects resulting from the combination of both fluoromethylated modifiers, we realize TFMBAI/TFP-based highly efficient PSCs with excellent operational stability and resistance to moisture, retaining over 96% of their initial efficiency after 500 h maximum power point tracking (MPPT) under simulated 1 sun irradiation and 97% of their initial efficiency after 1100 h of exposure under ambient conditions to a relative humidity of 60−70%.

Three hole-transporting materials (HTMs) based on the phenothiazine core containing 4,4-dimethyltriphenylamine (Z28), N-ethylcarbazole (Z29), and 4,4-dimethoxytriphenylamine (Z30) as the peripheral groups connected by double bonds were designed and synthesized. The HTMs were tested in mixed cation/anion perovskite solar cells (PSCs) of the composition [(FAPbI 3 ) 0.85 (MAPbBr 3 ) 0.15 ]. A power conversion efficiency (PCE) of 19.17% under 100 Mw cm −2 standard AM 1.5G solar illumination was obtained using Z30. Importantly, the devices based on Z30 show better stability compared to those using Z28 and Z29 when aged under ambient air of 40% relative humidity in the dark for 1008 h and under continuous sunlight soaking without encapsulation for 600 h. These results indicate that the 4,4-dimethoxytriphenylamine is a promising peripheral group in combination with the phenothiazine core, providing an alternative to develop small molecular HTMs for efficient and stable PSCs.

A rapid and simple process to prepare CH3NH3PbI3 perovskite solar cells in ambient air by adding 2-pyridylthiourea in the precursor solution was reported. The newly developed PSC exhibited an enhanced PCE of 18.2% along with enhanced stability under heat and humidity.

The toxicity of Pb and the instability of lead halide perovskites are the main obstacles to the practical application of lead-based nanocrystals (NCs). In this paper, all-inorganic Zn2+-doped lead-free perovskite (CsMn1–x Zn x Cl3) NCs were synthesized by a hot-injection method. Mn2+ ions were partially replaced by Zn2+ ions, and the energy transfer between Mn2+ was effectively suppressed. Because of this, excitons are more advantageously confined to the [MnCl6]4– octahedron. Target CsMn0.95Zn0.05Cl3 NCs were endowed with red emission at 654 nm with CIE coordinates of (0.70, 0.30) closing to the standard value of NTSC, and their photoluminescence quantum yield was increased to 77.1%, which is higher than those of Mn-based lead-free perovskites previously reported. Finally, a white light-emitting diode (LED) with adjustable emission from warm to cold white was realized by mixing Cs3MnBr5, CsMn0.95Zn0.05Cl3, and a blue phosphor on a 382 nm ultraviolet LED chip.