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Nonlinear absorption coefficient and modulation depth stand as pivotal properties of nonlinear optical (NLO) materials, while the existing NLO materials exhibit limitations such as low nonlinear absorption coefficients and/or small modulation depths, thereby severely impeding their practical application. Here we unveil that introducing Jahn–Teller distortion in a Mott‐Hubbard system, (MA)2CuX4 (MA=methylammonium; X=Cl, Br) affords the simultaneous attainment of a giant nonlinear absorption coefficient and substantial modulation depth. The optimized compound, (MA)2CuCl4, demonstrates a nonlinear absorption coefficient of (1.5±0.08)×105 cm GW−1, a modulation depth of 60 %, and a relatively low optical limiting threshold of 1.22×10−5 J cm−2. These outstanding attributes surpass those of most reported NLO materials. Our investigation reveals that a more pronounced distortion of the [CuX6]4− octahedron emerges as a crucial factor in augmenting optical nonlinearity. Mechanism study involving structural and spectral characterization along with theoretical calculations indicates a correlation between the compelling performance and the Mott‐Hubbard band structure of the materials, coupled with the Jahn–Teller distortion‐induced d‐d transition. This study not only introduces a promising category of high‐performance NLO materials but also provides novel insights into enhancing the performance of such materials. [ABSTRACT FROM AUTHOR]

Incorporating Jahn– Teller distortion into a Mott– Hubbard system emerges as an effective strategyfor developing high- performance nonlinear optical materials. In their Research Article ( e202406941), Chi Zhang, Zhipeng Huang employ lattice distortion to provide two distinct transition pathways with varying probabilities, while the Mott– Hubbard configuration ensures the transition sequence. This synergistic design unveils the excited- state absorption in ( MA) 2CuX4, enabling these materials to simultaneously exhibit a large nonlinear absorption coefficient and substantial modulation depth. [Extracted from the article]

Electrochemical N2 reduction is an environmentally friendly and sustainable approach for NH3 synthesis under mild conditions, while an efficient electrocatalyst is crucial for the N2 reduction reaction (NRR). Herein, we report Ti3+ self-doped TiO2−x nanowires on Ti mesh (Ti3+–TiO2−x/TM) as an efficient non-noble-metal NRR electrocatalyst with excellent selectivity. In 0.1 M Na2SO4, the Ti3+–TiO2−x/TM achieves a high faradaic efficiency of 14.62% with a NH3 yield of 3.51 × 10−11 mol s−1 cm−2 at −0.55 V vs. the reversible hydrogen electrode. Density functional theory calculations further reveal that introducing Ti3+ decreases the reaction energy barrier and increases the number of active sites on the TiO2 surface for the NRR. [ABSTRACT FROM AUTHOR]

Electrochemical N2 reduction is an environmentally friendly and sustainable approach for NH3 synthesis under mild conditions, while an efficient electrocatalyst is crucial for the N2 reduction reaction (NRR). Herein, we report Ti3+ self-doped TiO2−x nanowires on Ti mesh (Ti3+–TiO2−x/TM) as an efficient non-noble-metal NRR electrocatalyst with excellent selectivity. In 0.1 M Na2SO4, the Ti3+–TiO2−x/TM achieves a high faradaic efficiency of 14.62% with a NH3 yield of 3.51 × 10−11 mol s−1 cm−2 at −0.55 V vs. the reversible hydrogen electrode. Density functional theory calculations further reveal that introducing Ti3+ decreases the reaction energy barrier and increases the number of active sites on the TiO2 surface for the NRR. [ABSTRACT FROM AUTHOR]

The synthesis of NH3 heavily relies on the Haber–Bosch process suffering from a large amount of CO2 emission and energy consumption. Possessing eco-friendly and sustainable characteristics, electrochemical reduction is considered as a promising candidate for artificial N2 fixation under ambient conditions, but efficient electrocatalysts are crucial for the N2 reduction reaction (NRR). In this communication, we report that perovskite La2Ti2O7 nanosheets behave as an efficient NRR electrocatalyst with excellent selectivity under ambient conditions. In 0.1 M HCl, this catalyst achieves a high NH3 yield rate of 25.15 μg h−1 mgcat.−1 with a faradaic efficiency of 4.55% at −0.55 V vs. a reversible hydrogen electrode. Notably, it also shows high electrochemical stability. [ABSTRACT FROM AUTHOR]

Nonlinear absorption coefficient and modulation depth stand as pivotal properties of nonlinear optical (NLO) materials, while the existing NLO materials exhibit limitations such as low nonlinear absorption coefficients and/or small modulation depths, thereby severely impeding their practical application. Here we unveil that introducing Jahn-Teller distortion in a Mott-Hubbard system, (MA) 2 CuX 4 (MA=methylammonium; X=Cl, Br) affords the simultaneous attainment of a giant nonlinear absorption coefficient and substantial modulation depth. The optimized compound, (MA) 2 CuCl 4 , demonstrates a nonlinear absorption coefficient of (1.5±0.08)×10 5  cm GW -1 , a modulation depth of 60 %, and a relatively low optical limiting threshold of 1.22×10 -5  J cm -2 . These outstanding attributes surpass those of most reported NLO materials. Our investigation reveals that a more pronounced distortion of the [CuX 6 ] 4- octahedron emerges as a crucial factor in augmenting optical nonlinearity. Mechanism study involving structural and spectral characterization along with theoretical calculations indicates a correlation between the compelling performance and the Mott-Hubbard band structure of the materials, coupled with the Jahn-Teller distortion-induced d-d transition. This study not only introduces a promising category of high-performance NLO materials but also provides novel insights into enhancing the performance of such materials., (© 2024 Wiley-VCH GmbH.)

Electrochemical N2 reduction is an environmentally friendly and sustainable approach for NH3 synthesis under mild conditions, while an efficient electrocatalyst is crucial for the N2 reduction reaction (NRR). Herein, we report Ti3+ self-doped TiO2-x nanowires on Ti mesh (Ti3+-TiO2-x/TM) as an efficient non-noble-metal NRR electrocatalyst with excellent selectivity. In 0.1 M Na2SO4, the Ti3+-TiO2-x/TM achieves a high faradaic efficiency of 14.62% with a NH3 yield of 3.51 × 10-11 mol s-1 cm-2 at -0.55 V vs. the reversible hydrogen electrode. Density functional theory calculations further reveal that introducing Ti3+ decreases the reaction energy barrier and increases the number of active sites on the TiO2 surface for the NRR.

The synthesis of NH3 heavily relies on the Haber-Bosch process suffering from a large amount of CO2 emission and energy consumption. Possessing eco-friendly and sustainable characteristics, electrochemical reduction is considered as a promising candidate for artificial N2 fixation under ambient conditions, but efficient electrocatalysts are crucial for the N2 reduction reaction (NRR). In this communication, we report that perovskite La2Ti2O7 nanosheets behave as an efficient NRR electrocatalyst with excellent selectivity under ambient conditions. In 0.1 M HCl, this catalyst achieves a high NH3 yield rate of 25.15 μg h-1 mgcat.-1 with a faradaic efficiency of 4.55% at -0.55 V vs. a reversible hydrogen electrode. Notably, it also shows high electrochemical stability.