CAJ | 학술논문

以染料分子D5为原型,采用不同类型和数量的共轭桥单元来设计D-π-A型有机分子.采用密度泛函理论(DFT)和含时密度泛函理论(TDDFT)来模拟计算分子的形貌、分子轨道能级以及紫外-可见光谱,为染料敏化太阳能电池(DSSCs)的敏化分子寻找适合的共轭桥.采用“次甲基链”、“呋喃环”或“噻吩环”、“次甲基链和呋喃环”或“次甲基链和噻吩环”作为共轭桥单元,使得分子的吸收光谱依次红移.随着共轭桥单元的增加,分子的吸收光谱有剧烈的红移,但随着共轭桥单元数量的进一步增加,分子吸收光谱的红移现象减弱.分子的最低未占据分子轨道(LUMO)能级逐渐降低,而最高占据分子轨道(HOMO)能级逐渐升高.采用3个“次甲基链和呋喃环”或者“次甲基链和噻吩环”作为共轭桥时, HOMO能级已经高于氧化还原电解质的能级,而在极性溶液中,由2个“次甲基链和噻吩环”单元作为有机分子的共轭桥时,分子的 HOMO 能级已经高于氧化还原电解质的能级了.采用“次甲基链和呋喃环”或“次甲基链和噻吩环”单元作为有机分子的共轭桥时,吸收光谱有明显的红移,但对于DSSCs的敏化分子,这样的共轭桥单元只能有1-2个,不宜过多.
이염료분자D5위원형,채용불동류형화수량적공액교단원래설계D-π-A형유궤분자.채용밀도범함이론(DFT)화함시밀도범함이론(TDDFT)래모의계산분자적형모、분자궤도능급이급자외-가견광보,위염료민화태양능전지(DSSCs)적민화분자심조괄합적공액교.채용“차갑기련”、“부남배”혹“새분배”、“차갑기련화부남배”혹“차갑기련화새분배”작위공액교단원,사득분자적흡수광보의차홍이.수착공액교단원적증가,분자적흡수광보유극렬적홍이,단수착공액교단원수량적진일보증가,분자흡수광보적홍이현상감약.분자적최저미점거분자궤도(LUMO)능급축점강저,이최고점거분자궤도(HOMO)능급축점승고.채용3개“차갑기련화부남배”혹자“차갑기련화새분배”작위공액교시, HOMO능급이경고우양화환원전해질적능급,이재겁성용액중,유2개“차갑기련화새분배”단원작위유궤분자적공액교시,분자적 HOMO 능급이경고우양화환원전해질적능급료.채용“차갑기련화부남배”혹“차갑기련화새분배”단원작위유궤분자적공액교시,흡수광보유명현적홍이,단대우DSSCs적민화분자,저양적공액교단원지능유1-2개,불의과다.
Taking dye D5 molecules as the prototype, different types and different elemental quantities of conjugate π bridge was used to design D-π-A organic molecules. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) were adopted to simulate the geometric structures, molecular orbital energy levels, and UV-Vis absorption spectra of the molecules, with the aim of finding conjugate π bridge in the sensitizer molecules for dye-sensitized solar cel s (DSSCs). The absorption spectra of the molecules using“methenyl chains”,“furan rings”or“thiophene rings”,“methenyl chains and furan rings”, or“methenyl chains and thiophene rings”as conjugate π bridge showed a gradual y increasing red-shifting trend. With increases in the number of conjugate π bridge elements, the absorption spectrum showed an intense red-shift, which weakened gradual y; under the same conditions, the lowest unoccupied molecular orbital (LUMO) energy level of the molecules gradual y decreased, and the highest occupied molecular orbital (HOMO) energy level gradual y increased. The HOMO energy levels of the molecules with three“methenyl chain and furan ring”or“methenyl chain and thiophene ring”elements as conjugate π bridge were higher than the energy level of the redox electrolyte; in polar solutions, the HOMO energy levels of the molecules adopting two“methenyl chain and furan ring”or“methenyl chain and thiophene ring”elements as conjugate π bridge were higher than the energy level of the redox electrolyte. The absorption spectra of the organic sensitizer molecules with several“methenyl chain and furan ring”or“methenyl chain and thiophene ring”elements as conjugate π bridge showed an intense red-shift. These results showed that for DSSCs sensitizer molecules, it is not necessary to have many conjugate π bridge elements; one to two elements is typical y enough.