Yan Gao

Jul 25, 2024 | nature.com | Li Zhang |Yingzi Yuan |Ziqiang Xin |Yan Gao |Wenjing Wang |Chuangsheng Chen | +1 more

To examine the role of inequality in academic achievement, we analyse a cross-national dataset including data from three cycles from 2012 to 2018 from the PISA, an international assessment of 15-year-old students’ math, reading, and science performance. The Gini coefficient and gender inequality index (GII) were used as metrics for a country’s economic inequality and gender inequality, respectively. The results show that gender inequality has a negative association with academic achievement for both boys and girls. Moreover, gender inequality has a stronger association with academic achievement than does economic inequality. We also find that gender inequality in reproductive health may contribute substantially to the association between gender inequality and academic achievement. Despite substantial advances in gender equality worldwide, multisectoral and multilevel approaches from the community to the country level are needed to ensure substantial long-term reductions in economic, gender, and educational inequalities.

Feb 26, 2024 | nature.com | Kai Zhang |Yan Gao |Hongguang Meng |Zhengjie Zhu |Wei Peng |Zhenhuang Su | +1 more

The manufacturing of perovskite solar cells under ambient conditions is desirable, yet the efficiency of p–i–n perovskite solar cells fabricated in air still lags behind those made in an inert atmosphere. Here we introduce an ionic pair stabilizer, dimethylammonium formate (DMAFo), into the perovskite precursor solution to prevent the degradation of perovskite precursors. DMAFo inhibits the oxidization of iodide ions and deprotonation of organic cations, improving the crystallinity and reducing defects in the resulting perovskite films. We show the generation of additional p-type defects during ambient air fabrication that suggests the need for improving bulk properties of the perovskite film beyond surface passivation. Upon addition of DMAFo, we demonstrate that the efficiency of inverted p–i–n solar cells based on perovskite layers with 1.53-eV and 1.65-eV bandgaps fabricated under ambient conditions (25–30 °C, 35–50% relative humidity) increases by 15–20%. We achieve a certified stabilized efficiency of 24.72% for the 1.53-eV cell, on a par with state-of-the-art counterparts fabricated in an inert atmosphere. Manufacturing of perovskite solar cells under ambient conditions is desirable. Meng et al. show that dimethylammonium formate suppresses halide oxidation and deprotonation of organic cations, enabling air-processed inverted solar cells with 24.7% efficiency.