Increased performance of an organic light-emitting diode by employing a zinc phthalocyanine based composite hole transport layer

We demonstrate that the electroluminescent performances of organic light-emitting diodes are significantly improved by employing a zinc phthalocyanine （ZnPc）-based composite hole transport layer （c-HTL）. The optimum ris-（8-hydroxyquinoline）aluminum （Alq3）-based organic light-emitting diode with a c-HTL exhibits a lower turn-on voltage of 2.8 V, a higher maximum current efficiency of 3.40 cd/A and a higher maximum power efficiency of 1.91 lm/W, which are superior to those of the conventional device （turn-on voltage of 3.8 V, maximum current efficiency of 2.60 cd/A, and maximum power efficiency of 1.21 lm/W）. We systematically studied the effects of different kinds of N’-diphenyl-N,N’-bis（1-naphthyl）（1,1’-biphenyl）-4,4’diamine （NPB）：ZnPc c-HTL. Meanwhile, we also investigate their mechanisms different from that in the case of using ZnPc as buffer layer. The specific analysis is based on the absorption spectra of the hole transporting material and current density–voltage characteristics of the corresponding hole-only devices.

Hierarchical porous carbon derived from one-step self-activation of zinc gluconate for symmetric supercapacitors with high energy density

Porous carbons with high specific area surfaces are promising electrode materials for supercapacitors.However,their production usually involves complex,time-consuming,and corrosive processes.Hence,a straightforward and effective strategy is presented for producing highly porous carbons via a self-activation procedure utilizing zinc gluconate as the precursor.The volatile nature of zinc at high temperatures gives the carbons a large specific surface area and an abundance of mesopores,which avoids the use of additional activators and templates.Consequently,the obtained porous carbon electrode delivers a satisfactory specific capacitance and outstanding cycling durability of 90.9%after 50000 cycles at 10 A·g^(-1).The symmetric supercapacitors assembled by the optimal electrodes exhibit an acceptable rate capability and a distinguished cycling stability in both aqueous and ionic liquid electrolytes.Accordingly,capacitance retention rates of 77.8%and 85.7%are achieved after 50000 cycles in aqueous alkaline electrolyte and 10000 cycles in ionic liquid electrolyte.Moreover,the symmetric supercapacitors deliver high energy/power densities of 49.8 W·h·kg^(-1)/2477.8 W·kg^(-1) in the Et4NBF4 electrolyte,outperforming the majority of previously reported porous carbon-based symmetric supercapacitors in ionic liquid electrolytes.

合理设计多电子转移机制实现更好的水系锌-有机电池

由于环境相容性好、分子结构可定制和有机物资源丰富等优势,水系锌-有机物电池(AZOBs)成为构建新一代大规模储能系统的关键技术.然而,电导率差、有机物溶解和单一活性基团等问题严重限制了有机物正极材料的倍率性能、稳定性和比容量.因此,具备多氧化还原中心和稳定骨架的有机物正极材料对于实现高性能有机物正极材料至关重要.这些多官能团有机物可协同作用并激发基于多电子转移的氧化还原反应,进而促进H^(+)/Zn^(2+)共嵌以显著提升电池性能.本文探索了多官能团有机物电极的分子结构与其氧化还原反应机理之间的构效关系.本文综述了多官能团有机正极材料在提高氧化还原电位、比容量、动力学以及稳定性等方面面临的挑战和解决策略,为进一步开发先进AZOBs的关键正极材料提供了重要基础.