Spectroscopic Ellipsometry Studies of CuPc and Other Materials for Organic Light-Emitting Devices

Red top-emitting organic light-emitting device with improved efficiency and saturated color

“…I 0 (l) is the free-space (no cavity) electroluminescence intensity at l, which is difficult to determine exactly and can be approximated with electroluminescent spectra of emitter. In our calculation, the optical constants of metals are taken from the literature [10], while those of the organic materials are measured using a variable angle spectroscopic ellipsometer [11]. The resonant wavelength of the measured device is 636 nm, which is close to the calculated result depicted in Fig.…”

Optical response and emission waveguiding in rubrene crystals

“…[1][2][3][4][5] While its high carrier mobility is well documented, there are relatively few studies on the optical properties of crystalline rubrene, which are fundamental for developing new strategies in device design. To date, ellipsometry measurements have been reported 6 and the isotropic dielectric function deduced only in the case of polycrystalline rubrene films deposited by evaporation on silicon substrates. In the single crystal form, its strong anisotropy has prevented a full optical characterization, thus limiting the understanding of the intermolecular interactions in the solid.…”

Interfacial processes in small molecule organic solar cells

“…If the thickness of organic film is less than the absorption length of the material at the wavelength of the laser beam, the initial transient photovoltage of exction dissociation could not be observed. For sample [ITO/CuPc(105 nm)/Al](absorption length of CuPc ∼ 120 nm [23], only positive photovoltage signal is observed, as shown in Figure 7. This indicates that the negative signal from exciton dissociation at the ITO/CuPc interface is surpassed by the strengthened positive signal.…”

“…Because of the different separation distance of these two processes, compared to the carrier separation, the exciton dissociation is a fast process which only takes several nanoseconds. For these samples [ITO/organic layer/cathode], the thickness of organic layer is much larger than the absorption length of the material (NPB ∼ 117 nm, CuPc ∼ 120 nm [23], C 60 ∼ 35 nm [8]) at the wavelength of the laser beam (355 nm). The excited excitons are mainly created in the area adjacent to the ITO/organic interface.…”