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N,N′-二苯基-N,N′-二(3-甲苯基)-1,1′-联苯-4,4′-二胺(TPD)分子已证明能够在掺杂和非掺杂平面波导结构中产生受激发射,然而对于该分子激射特性的机理却很模糊.为了得到其激射特性的微观解释,我们通过实验和量化理论研究TPD分子的吸收、光致发光、受激发射以及与TPD分子结构类似的两个分子:1,4-二(二苯胺基)联苯(DDB)和N,N′-二苯基-N,N′-二(1-萘基)-1,1′-联苯-4,4′-二胺(NPB).我们发现,DDB分子具有与TPD分子相似的自发辐射放大(ASE)特性,然而NPB分子却没有ASE特性,尽管其斯托克斯位移较大,约0.754eV.量子化学计算分析中,我们利用密度泛函理论(DFT)和弗朗克-康登(Franck-Condon)原理研究分子在电子基态和激发态的分子构型以及电子基态的振动能级.理论分析表明,对于TPD和DDB分子,一些苯环中的较强高频拉伸模式(1199～1664cm-1)对PL谱中的第一振动带(0-1跃迁)有显著贡献,该振动带有利于形成激光的四能级系统.而对于NPB分子,相对大的萘基基团取代了TPD和DDB分子外围的甲基与苯环,会产生一些较强的分子低频振动模式(11～689cm-1),这些低频振动模式则会破坏激光四能级系统.研究结果有助于深刻理解有机分子的激射特性,为新型激射材料的设计和应用提供了理论基础.
N, N’-diphenyl-N, N’-bis (3-methylphenyl) -1,1’-biphenyl-4,4’-diamine (TPD) molecules have been shown to be capable of both doped and non- However, the mechanism of the molecular lasing behavior is very vague.In order to obtain a microscopic explanation of the lasing properties, we study the absorption and photoluminescence of TPD molecules through experiments and quantitative theories Excimer radiation and two molecules similar in structure to the TPD molecule: 1,4-bis (diphenylamino) biphenyl (DDB) and N, N’-diphenyl-N, -1,1’-biphenyl-4,4’-diamine (NPB). We found that DDB molecules have spontaneous emission amplification (ASE) similar to that of TPD molecules, whereas NPB molecules have no ASE properties, The TOKs shift is larger, about 0.754eV. In quantum chemical calculation, we use the density functional theory (DFT) and the Franck-Condon principle to study the molecular structure of the ground state and the excited state And the vibrational energy levels of the ground state of the electron.The theoretical analysis shows that for the TPD and DDB molecules, the first high frequency band (1199 ~ 1664cm-1) 1 transition) has made a significant contribution to that For NPB molecules, a relatively large naphthyl group replaces the methyl and benzene rings at the periphery of the TPD and DDB molecules, resulting in some stronger modes of molecular low frequency vibration (11 ~ 689cm-1), these low-frequency vibration modes will destroy the laser four-level system.The results contribute to a deep understanding of the lasing characteristics of organic molecules and provide a theoretical basis for the design and application of new lasing materials.