Poly visible spectrum

It was noted early in our studies of monomeric analogs of I that significant changes occurred in the visible spectrum upon conversion between oxidation states changes which translate into vivid, visual differences in color. These differences in color are also very apparent in poly-I and thus make it of interest as an e 1 ectrochromic material (61. 

Polymer photodetectors, on the other hand, are rapidly becoming feasible for commercial applications. Recently a full-color optical scanner was made from an array of 102 polymer photodiodes [315]. Poly(3-octyl thiophene), P30T, was chosen as the polymer for the scanner because its band gap is 1.9 eV (650 nm), which allows it to absorb light at all wavelengths in the visible spectrum. Red, green, or blue filters were placed in front of the photodiodes to make them sensitive to a particular color. This prototype scanner demonstrates the feasibility of making large two-dimensional full-color detector arrays on a wide variety of surfaces. 

Andersson and coworkers have prepared solar cells based on blends of poly(2,7-(9-(2 -ethylhexyl)-9-hexyl-fluorene)-fl/t-5,5-(4, 7 -di-2-thienyl-2, l, 3 -benzothiadiazole) (223) and PCBM [416]. The polymer shows a Amax (545 nm) with a broad optical absorption in the visible spectrum and an efficiency of 2.2% has been measured under simulated solar light. The same group has also reported the synthesis of low bandgap polymers 200 (1 = 1.25 eV) and 224 (1 = 1.46 eV) which have been blended with a soluble pyrazolino[70]fiillerene and PCBM, respectively, to form bulk heterojunction solar cells of PCE of 0.7% [417] and 0.9% [418]. Incorporation of an electron-delident silole moiety in a polyfluorene chain affords an alternating conjugated copolymer (225) with an optical bandgap of 2.08 eV. A solar cell based on a mixture 1 4 of 225 and PCBM exhibits 2.01% of PCE [419]. 

Poly(p-phenylene) (PPP) is an interesting material for electrooptical applications as its bandgap is in the blue region of the visible spectrum and its thermal stability is combined with high PL. However, it is insoluble and infusible making it difficult to fabricate thin films. In the early stages of the search for PPP synthesis the limitations were related to the difficulties in the preparation of polymers possessing a defined architecture. Since rally a few classical ... 

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