Synthesis, electrochromic properties and flash memory behaviors of novel D-A-D polyazomethines containing EDOT and thiophene units

A series of novel polyazomethines containing EDOT and thiophene units coded as PEDOTs (PEDOT-TPA, PEDOT-TDD, PEDOT-THIO, PEDOT-APM) and PTHIOs (PTHIO-TPA, PTHIO-TDD, PTHIO-THIO, PTHIO-APM) were synthesized successfully. They were gained in short time, low cost and mild reaction conditions by a straightforward synthetic path. It can be easily found from the electrochemical properties of these polymers that the polymers containing 3,4-ethylenedioxythiophene (EDOT) unit (PEDOTs) have lower initial oxidation potentials as compared to the polymers containing thiophene unit (PTHIOs). Spectroelectrochemical properties reveal that all of the polymer films exhibit outstanding multielectrochromic behaviors, distinct color contrast and excellent electrochemical stabilities. Kinetic studies show that the PEDOT-TPA film has the shortest response time (a color switching time of 4.54 s and a bleaching time of 3.88 s at 428 nm) and the PEDOT-THIO film exhibits the highest CE of 343.56 cm 2  C −1 . Typical I-V characteristics of the ITO/plymer/Al memory devices exhibit that all the memory devices based on PEDOTs and PTHIOs exhibited nonvolatile flash memory characteristics, with an ON/OFF current density ratio of 10 3 -10 4 and low threshold voltages (around 1 V). Thus, these characteristics illustrate that these novel polymers have great potential in optoelectronics applications as electrochromic materials and memory devices.