摘要
本文利用密度泛函(DFT)和含时密度泛函理论(TD-DFT),研究了单一染料(C239、C259和修饰的C259(C259-N))以及共敏化染料(C239+C259和C239+C259-N)的电子结构和光学性能.结果表明,单一和共敏化条件下,新设计的含二噻吩并吡咯单元(DTP)的C259-N表现出与含环戊二噻吩单元(CPDT)的C259相近的光学性质.与单一染料相比,共敏化染料的光捕获率曲线未出现低谷,且在最大吸收处,其摩尔吸光率也有所提高.对共敏化染料/TiO_2复合物的研究表明,由3个O-Ti键和1个氢键形成的A共敏化模式下的共敏化体系稳定性较高,其中,含苯甲酸染料的垂直吸附一方面有利于染料/TiO_2界面的电子注入,另一方面可有效减轻界面的电荷复合.本文结果可为设计更加高效的有机共敏化剂提供理论依据.
By using density functional theory(DFT) and time-dependent DFT(TD-DFT) methods,the electronic structures and optical properties of a single dye(C239,C259 and C259-N) and co-sensitized dyes(C239+C259 and C239+C259-N) were studied.It is found that the effect of the replacement of dithienopyrrole(DTP) with cyclopentadithiophene(CPDT) in C259 on dye performance is negligible.There is no valley in the light-harvesting efficiency curve for the co-sensitized dyes,and the molar absorbtivity of the co-sensitized dyes at the maximum absorption has been improved compared with a single dye.Further investigations on the co-sensitized dye/TiO_2complexes show that the A co-sensitization mode with the formation of three O-Ti bonds and a new hydrogen bond is more stable.The co-sensitized dye with the benzoic acid group can stay perpendicular on the titanium surface,this is favourable for electron injection and can weaker electron-hole recombination at dye/TiO_2 interface.Our results can supply a guideline for experimental design of more efficient co-sensitized organic dyes for dye-sensitized solar cells(DSSCs).
出处
《中国科学:化学》
CAS
CSCD
北大核心
2015年第12期1254-1262,共9页
SCIENTIA SINICA Chimica
基金
国家重点基础研究发展计划(2011CBA00701)
国家自然科学基金(21473010)的资助
关键词
染料敏化太阳能电池
有机染料
共敏化
吸收光谱
光捕获率
dye-sensitized solar cell
organic dye
co-sensitization
absorption spectrum
light-harvesting efficiency