Li Yang, Wang Junting, Yuan Yi, Zhang Min, Dong Xiandui, Wang Peng
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Department of Chemistry, Zhejiang University, Hangzhou 310028, China.
Phys Chem Chem Phys. 2017 Jan 18;19(3):2549-2556. doi: 10.1039/c6cp07916d.
Two perylene dyes characteristic of electron-donors phenanthrocarbazole (PC) and carbazyl functionalized PC are selected to study the complicated dynamics of excited states and charge carriers, which underlie the photovoltaic parameters of dye-sensitized solar cells (DSCs). We have combined femtosecond fluorescence up-conversion and time-resolved single-photon counting techniques to probe the wavelength-dependent photoluminescence dynamics of dye molecules not only dissolved in THF but also grafted on the surface of oxide nanoparticles. Excited state relaxation and electron injection both occur on a similar timescale, resulting in a very distributive kinetics of electron injection. It is also found that the carbazyl ancillary electron-donor causes a faster electron injection, which over-compensates the adverse impact of a slightly shorter lifetime of the equilibrium excited state. Nanosecond transient absorption and transient photovoltage decay measurements have shown that conjugating carbazyl to PC can effectively slow down the kinetics of charge recombination of electrons in titania with both photo-oxidized dye molecules and triiodide anions, improving the cell photovoltage.
选择两种具有电子供体菲咯并咔唑（PC）和咔唑基官能化PC特性的苝染料，以研究激发态和电荷载流子的复杂动力学，这些动力学是染料敏化太阳能电池（DSC）光伏参数的基础。我们结合了飞秒荧光上转换和时间分辨单光子计数技术，不仅探测溶解在四氢呋喃中的染料分子，还探测接枝在氧化物纳米颗粒表面的染料分子的波长依赖性光致发光动力学。激发态弛豫和电子注入都发生在相似的时间尺度上，导致电子注入的动力学非常分散。还发现咔唑辅助电子供体导致更快的电子注入，这过度补偿了平衡激发态寿命略短的不利影响。纳秒瞬态吸收和瞬态光电压衰减测量表明，将咔唑与PC共轭可以有效减缓二氧化钛中电子与光氧化染料分子和三碘化物阴离子的电荷复合动力学，提高电池光电压。
