We report a write-once-read-many polymeric memory device that can be read by both electrical and optical methods. The device consists of two layers of conjugated polymer blends sandwiched between a metal electrode and a transparent electrode. One of the polymer blends functions as an ion-trapping, electrochromic layer, while the other polymer blend functions as a light-emitting electrochemical cell. Recording is facilitated by applying a negative writing voltage on the device. Reading can be performed by either probing with a low positive voltage, probing with a laser beam, or by measuring the light emission intensity from the device.
Full-color polymer light-emitting diode (PLED) arrays presently are mainly produced by ink-jet printing. Here, we
report a new approach for fabricating full-color PLED arrays that takes advantage of the low-cost and high throughput
spin-coating and photo-patterning processes. Compared to previous approaches that also employed photo-patterning, our
approach does not require wet processing steps, and the spectra of the colors emitted are not sensitive to the photopatterning
time. Because the photo-pattering is a traditional technology which was proved to be successfully used in
producing liquid crystal displays and other electrical productions, this method may provide a low-cost and high
throughput procedure to manufacture polymeric flat-panel display devices.
The reorientational mobilities of molecules in nonlinear optical (NLO) polymers poled by thermal-assisted (TAP) and photo-assisted (PAP) electric-field poling are compared by measuring the temporal development of the NLO properties under a secondary poling voltage at a temperature below the glass transition temperature of the polymer. By comparing the experimental results with a theoretical model that is based on independent chromophores with a distribution of relaxation times, it was found that the secondary poling profile for a polymer poled by PAP is very well described by the theory. This shows that the chromophores can indeed be regarded as independent to each other as far as their relaxations are concerned. The secondary poling profile for a polymer poled by TAP, on the other hand, did not agree with the theory. The discrepancy of the behaviors between the two poling methods suggests that the relaxation patterns observed for polymers poled by TAP may be affected by factors not intrinsic to the polymer properties. This result may have an impact on the assessment of the long-term reliability of photonic devices based on thermally poled NLO polymers.