Nonlinear Elements with Polyacetylenes

Nearly thirty papers have been published on the possible polyacetylene applications as nonlinear elements including rectifying cells [105, 128-134] and heterojunctions [135-139]. 

Schottky photovoltaic elements were proposed because of the good conformity of the solar spectrum with the polyacetylene forbidden gap. The photovoltaic spectra for (CH)n-Al structure and volt-current characteristic for (CH) -nCdS heterojunction are presented in Fig. 19 and Fig. 20 respectively. 

The energy conversion efficiency is estimated to be 0.3% relative to the energy absorbed within the depletion layer region. This conversion efficiency is remarkably higher than that of PVC-TNF. The rectification factor is 103, short circuit current 50 pA-cm-2, open circuit voltage 0.8 V, fill factor 0.25. 

The heterojunctions of the polyacetylene were realized not only with inorganic photoconductors but also with organic polymers [139]. The results obtained show good similarity with barrier and heterojunction characteristics for inorganic semiconductors. Photoelectrochemical cell for solar energy conversion with polyacetylene electrodes and Na2S, electrolyte had an efficiency of 1 % at 2.4 eV [140], The complicated phenomena take place at the electrodeelectrolyte interface. 

In conclusion, one can say that the possibility of a sharp change of the polyacetylene conductivity opens vast perspectives for new technologies in the field of molecular electronics. The cheap, simply made devices can be designed with small power consumption and broad excellent physico-chemical properties. 

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