Haijun Tao

碳基无空穴传输层钙钛矿太阳能电池(C-PSCs)因其替换了昂贵的贵金属电极, 以及去掉了稳定性差的空穴传输材料而受到广泛关注. 但是C-PSCs内部载流子分离和传输性能差阻碍了效率的提高, 而内建电场的增强可以改善载流子传输性能从而提升电池光电性能. 本文将铁电材料钛酸钡(BaTiO₃)粉末作为添加剂引入钙钛矿前驱液中制备C-PSCs, 改善钙钛矿薄膜形态, 降低薄膜缺陷密度及提高C-PSCs载流子传输性能. 结果表明, 当BaTiO₃质量分数为1.0%时, 钙钛矿薄膜均匀致密, 电池的光电转换效率最高. 对薄膜施加正向电压极化处理后, 铁电材料BaTiO₃剩余极化电场增大了内建电场, 为载流子输运和萃取提供充足的动力, 从而抑制非辐射复合的发生; 同时耗尽层宽度增大, 反向饱和电流减小, 电池性能显著提升, 优化后最佳器件效率为9.02%. 本文为钙钛矿吸收层掺杂实现内建电场调控提供了一种有效策略.

Scientists are increasingly paying attention to using theoretical design as a guide combined with modern in‐situ characterization techniques to develop catalysts with high activity, low cost, and long‐term life. The review discusses the progress of catalyst theoretical design and corresponding experiments based on three typical oxygen evolution catalytic mechanisms, including the adsorbate evolution, lattice oxygen‐mediated, and unconventional bifunctional mechanisms. This work briefly describes the commonly used tools and descriptors in theory as well as the electrochemical techniques and characterizations in experiments. Our purpose is to sort out the ways to closely integrate the theoretical method and experimental verification from the perspective of reaction mechanism, and to provide some experience reference for the future development of theoretical tools and experimental technologies.

The well-designed planar micro-supercapacitors can be manufactured through a variety of techniques for the applications in flexible electronics, biosensors, power grids and integrated chips.

During polarization treatment, the residual polarization electric field generated by BaTiO₃ increased E_bi of the cells and width of the depletion layer, promoted extraction and separation of carriers, and improved photoelectric performance of PSCs.

The hierarchical nanosheet-based Ni ₃ S ₂ microspheres directly grew on Ni foam using a two-step hydrothermal method. The microsphere with a diameter of ∼1 microns and a rough surface was well connected to each other without any binders to provide a larger specific surface area, shorter ion/electron diffusion paths, richer electroactive sites as a supercapacitor electrode. As a three-electrode supercapacitor, it delivers a high specific capacity of 981.8 F g ⁻¹ at 2 A g ⁻¹ , an excellent rate capability of 436.4 F g ⁻¹ at 12 A g ⁻¹ , and a good cycling stability of 950.9 F g ⁻¹ with 96.9% retention after 1000 cycles at 2 A g ⁻¹ . Furthermore, an asymmetric supercapacitor based on Ni ₃ S ₂ -microsphere as a positive electrode and active carbon as a negative electrode shows a high energy density of 29.4 Wh kg ⁻¹ at 324.5 W kg ⁻¹ and a high power density of 3197.6 W kg ⁻¹ at 15.1 Wh kg ⁻¹ . This work demonstrates that nanosheet-based Ni ₃ S ₂ microspheres coated Ni foam can be an effective electrode for a real supercapacitor.