High‐qality self‐assembled heterostructures for polymer LEDs have been fabricated from PPV and newly synthesized copolymers of PPV and naphthalene. It is shown that the layer‐by‐layer self‐assembly of multilayer structures has advantages with respect to control of the thickness and homogeneity of the polymer films compared to the conventional spin coating technique. The fabrication and characterization of the heterostructures are detailed and features of the electroluminescence and photoluminescence discussed.

A fluorinated poly(p-phenylenevinylene) analogue, co(TFPV-PV), has been prepared by copolymerization of fluorinated and nonfluorinated bissulfonium salt monomers. Conversion and yield decreased as a function of fluorine substitution. The UV-vis absorption was strongly shifted to the blue with increasing fluorine content. Complementary shifts in photoluminescence spectra were not observed, presumably because the fluorinated segments of the copolymer are very weakly luminescent relative to nonfluorinated segments. The photoluminescence spectra are therefore similar to those found for poly(p-phenylenevinylene) in the past. The co(TFPV-PV) compounds showed electroluminscence at an ac potential of ∼10 V (rms, 600 Hz) between ITO and Al electrodes. Maxima were shifted slightly to the blue with an increase in fluorine.

We describe a method to microfabricate a light emitting diode array with pixels based on conjugated electroluminescent polymers sandwiched between appropriate electrodes. This method, based on direct photoablation with the 193 nm emission of an excimer laser, maintains the properties of these unique polymers. The technique as described here has already achieved an array of 20 μm×20 μm pixels with enhanced electroluminescence (EL) from these pixels and possible spectral tuning of the EL by the application of varying external field. This method can be extended to achieve nanometer dimensionalities using near-field nanolithography.

We present photoluminescence (PL), UV absorption, electroluminescence and x-ray reflectivity studies of self-assembled multilayer films containing alternate layers of conjugated copolymers, and nonconjugated insulating polymers. We show that the PL emission properties of these organic quantum wells can be ‘‘tuned’’ by a proper choice of the conjugated copolymer and the thickness of the insulating layers. Particularly, some of the self-assembled ultrathin films containing thin (∼7 Å) insulating polymeric layers exhibit a blue shift upon decreasing the thickness of the assembly. The PL shift is roughly proportional to 1/d2 where d is the thickness of the assembly, as expected for confined photogenerated electron-hole pair in an infinite square potential well. In contrast, the PL emission of similar assemblies but containing thick (∼40 Å) insulating layers is independent of the assembly thickness and exhibit emission in the blue. This may suggest a strong spatial confinement. Light emitting diodes based on self-assembled multilayer films with improved efficiency and stability and with threshold voltage as low as 2.6 V could be fabricated.

Color tuning of the electro‐ and photoluminescence from naphthalenevinylene–PPV–based light‐emitting diodes between yellow‐green and red is reported. Band structure considerations are employed to explain that chemical selectivity and selective band‐gap tuning are observed in some of the copolymers studied but not in others. It is also found that light emission can be tuned by changing the thickness of the copolymer film in the LED.