RESUMEN
Organic light emitting devices, in particular, properties of polymer light-emitting transistors with printed electrodes and bilayer printed devices with in-plane emission have been investigated and discussed. The semitransparent device based on poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) with Ag-nanowire source/drain and transparent carbon nanotube gate electrodes exhibits ambipolar and light-emitting characteristics. For the devices with oriented poly(9,9-dioctylfluorene) (F8) films, enhanced electron and hole field-effect mobilities have been achieved by aligning the polymer chains parallel to the transport direction. The bilayer device using F8BT lower layer and oriented F8 upper layer with the channel direction parallel to the polymer orientation exhibits improved EL intensity and higher external quantum efficiency than that with the channel direction perpendicular to the polymer chains orientation. The optical pulses of more than 100 Hz frequency are generated by directly modulating a bilayer device with an in-plane emission pattern.
RESUMEN
Organic position-sensitive detector (OPSD) based on copper phthalocyanine CuPc:fullerene C60 bulk-heterojunction with an inverted structure have been fabricated using aluminum doped ZnO (ZnO:Al) as a resistive layer, which is prepared by sol-gel method. The resistance length of the one-dimensional PSD is fixed at 5 mm, and the Ag common electrode is fabricated by vacuum evaporation within the 100-µm width. The current density-voltage characteristics with different structures of photodetector, the influence of ZnO:Al resistivity on the thickness and the position characteristics of PSDs are investigated. The experimental results indicate that the architecture, which uses an inverted structure, increases sensitivity under red light illumination compared to the conventional structure. In addition, the thickness of the ZnO:Al has influence on the position characteristics. The resistivity of ZnO:A film with Al doping concentration of 2 mol% prepared in this study is around 150 Ωcm and it increases from less than approximately 400 nm-thickness. These characteristics seem to be correlated with the properties of ZnO:AI resistive layer. For a device with a 620 nm-thick ZnO:Al layer, the measured position values obtained from the output photocurrent agree with the actual position values under red laser light illumination. CuPc:C60 OPSD with an inverted structure exhibits red light sensitivity, high incident-photon-to-current conversion efficiency of above 80% at -3 V and linearity error of 5.9% at -2 V.