轨道能级差
色素敏化染料
氧化还原
化学
电解质
吸收(声学)
超快激光光谱学
光化学
电化学
吸收光谱法
离子
材料科学
无机化学
光谱学
电极
物理化学
分子
有机化学
光学
物理
量子力学
复合材料
作者
Chao Teng,Xichuan Yang,Shifeng Li,Ming Cheng,Anders Hagfeldt,Li‐Zhu Wu,Licheng Sun
标识
DOI:10.1002/chem.201000460
摘要
Abstract A series of novel metal‐free organic dyes TC301 – TC310 with relatively high HOMO levels were synthesized and applied in dye‐sensitized solar cells (DSCs) based on electrolytes that contain Br − /Br 3 − and I − /I 3 − . The effects of additive Li + ions and the HOMO levels of the dyes have an important influence on properties of the dyes and performance of DSCs. The addition of Li + ions in electrolytes can broaden the absorption spectra of the dyes on TiO 2 films and shift both the LUMO levels of the dyes and the conduction band of TiO 2 , thus leading to the increase of J sc and the decrease of V oc . Upon using Br − /Br 3 − instead of I − /I 3 − , a large increase of V oc is attributed to the enlarged energy difference between the redox potentials of electrolyte and the Fermi level of TiO 2 , as well as the suppressed electron recombination. Incident photon to current efficiency (IPCE) action spectra, electrochemical impedance spectra, and nanosecond laser transient absorption reveal that both the electron collection yields and the dye regeneration yields ( Φ r ) depend on the potential difference (the driving forces) between the oxidized dyes and the Br − /Br 3 − redox couple. For the dyes for which the HOMO levels are more positive than the redox potential of Br − /Br 3 − sufficient driving forces lead to the longer effective electron‐diffusion lengths and almost the same efficient dye regenerations, whereas for the dyes for which the HOMO levels are similar to the redox potential of Br − /Br 3 − , insufficient driving forces lead to shorter effective electron‐diffusion lengths and inefficient dye regenerations.
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