Graf Lukas, Liu Fupin, Naumann Marco, Roth Friedrich, Debnath Bipasha, Büchner Bernd, Krupskaya Yulia, Popov Alexey A, Knupfer Martin
IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany.
Institute of Experimental Physics, TU Bergakademeie Freiberg, Leipziger Straße 23, 09599 Freiberg, Germany.
ACS Omega. 2022 Jun 8;7(24):21183-21191. doi: 10.1021/acsomega.2c01987. eCollection 2022 Jun 21.
High-quality single crystals of the organic semiconductor (1,2;8,9)-dibenzopentacene were grown via physical vapor transport. The crystal structure-unknown before-was determined by single-crystal X-ray diffraction; polarization-dependent optical absorption measurements display a large anisotropy in the plane of the crystals. The overall Davydov splitting is ∼110 meV, which is slightly lower than that in the close relative pentacene (120 meV). Momentum-dependent electron energy-loss spectroscopy measurements show a clear exciton dispersion of the Davydov components. An analysis of the dispersion using a simple 1D model indicates smaller electron- and hole-transfer integrals in dibenzopentacene as compared to pentacene. The spectral weight distribution of the excitation spectra is strongly momentum-dependent and demonstrates a strong momentum-dependent admixture of Frenkel excitons, charge-transfer excitons, and vibrational modes.
通过物理气相传输法生长出了高质量的有机半导体（1,2；8,9）-二苯并并五苯单晶。此前未知的晶体结构通过单晶X射线衍射得以确定；偏振相关的光吸收测量表明，在晶体平面内存在很大的各向异性。总的达维多夫分裂约为110毫电子伏，略低于其近亲并五苯（120毫电子伏）。动量相关的电子能量损失谱测量显示出达维多夫分量明显的激子色散。使用简单的一维模型对色散进行分析表明，与并五苯相比，二苯并并五苯中的电子和空穴转移积分更小。激发光谱的光谱权重分布强烈依赖于动量，并表明弗伦克尔激子、电荷转移激子和振动模式存在强烈的动量相关混合。
