The high strain cyclopropane as σ block model inserted in organic semiconductors to tune the structures and optical properties was investigated by the density functional theory method. The band gaps and absorption peaks of 1,2-disubstituted cyclopropanes were between the corresponding alkanes and olefins. The cis-isomers had higher steric strain between two substituents and lower symmetry than the trans-isomers in ground-state structures. The electronic transitions (S0→S1) were mainly on the aryl parts, which were stronger coherence with surrounding atoms in cis-isomers, while the trans-isomers were on the cyclopropyl. Furthermore, 1,2-disubstituted cyclopropanes (1A, 1B, 2A, 4B) could respond to the charge stimulation, which are potential materials for organic electronics and mechatronics.
Highly efficient blue phosphorescent organic light-emitting diode (OLED) is achieved by using a blend of biphenyl (spiro[fluorene-9,9'-xanthen]-2-yl) phosphine oxide (SFX2PO) and various of hole- or electron-transporting materials such as di-[4-(N,N-di-p-tolyl-amino)-phenyl]cyclohexane (TAPC), 2,2',2"-(1,3,5-benzinetriyl)-tris(1- phenyl-1-H-benzimidazole) (TPBi) and 4,4',4"-tris(carbazol-9-yl)triphenylamine (TCTA). The results show that TCTA and SFX2PO can partially form exciplex and have better charge carrier balance performance. The driving voltage and efficiency are improved in a multi-player device with TCTA and SFX2PO as the co-host. The device shows a maximum current efficiency of 22.75 cd•A–1, which is nearly two folds over the device using SFX2PO or phosphine oxide spirobifluorene derivative (SPPO1) as a single host.