Piangkhwan Wanitchang. Organic light emitting devices based on new anthracene derivatives as light emitting materials. Master's Degree(Physics). Mahidol University. Mahidol University Library and Knowledge Center. : Mahidol University, 2009.
Organic light emitting devices based on new anthracene derivatives as light emitting materials
Abstract:
The characteristics of new anthracene derivatives; 9,10-bis(dodecylthio)
anthracene (ADT) and 9,10-bis(dodecyloxy)anthracene (ADO), were studied. The
melting temperature of ADT and ADO obtained from the differential scanning
calorimetry (DSC) was observed at 76 and 65 °C, respectively. The UV-visible
absorption spectrum showed the absorption edge of ADT and ADO at 431 and 425
nm, respectively, which indicated an approximate energy gap of 2.9 eV. The
photoluminescent spectrum revealed an emission peak of ADT at 450 nm. The
HOMO levels of ADT and ADO calculated from the oxidation onset potential of
cyclic voltammogram were 5.7 and 5.4 eV, respectively. The LUMO levels of
ADT and ADO derived from the measured HOMO levels and the optical energy
gap were 2.8 and 2.5 eV, respectively.
The organic light emitting devices based on new anthracene derivatives as
emitting materials were fabricated and characterized to determine the electrical and
optical characteristics. PEDOT:PSS was used as a hole transporting layer. The
emissive layer was deposited by a spin casting technique with anthracene
derivative doping into polymer host matrix, poly(N-vinyl carbazole) (PVK). When
using ADT as an emitting material, the electroluminescence of ADT doped devices
with various concentrations centered at 460-475 nm. The device with ADT 30
wt% doping in PVK had the highest performance. The maximum luminance of
318 cd/m2 was obtained at 11.5 V and the maximum current efficiency of 0.28
cd/A was exhibited at 9 V. The CIE coordinates of (0.16,0.22) were obtained and
they indicated an emission color in the blue region. When using ADO as emitting
material, the electroluminescence of ADO doped devices with various
concentrations centered around 450-460 nm. The device with ADO 0.5 wt%
doping in PVK had the highest performance. The maximum luminance of 190
cd/m2 was obtained at 11 V and the maximum current efficiency of 0.07 cd/A was
exhibited at 10 V. The CIE coordinates of (0.20,0.17) were obtained and they
indicated an emission color in the blue region.