4-KETO-BACTERIORHODOPSIN FILMS AS A PROMISING PHOTOCHROMIC AND ELECTROCHROMIC BIOLOGICAL-MATERIAL

Photochromic and electrochromic spectral properties of 4-keto-bacterio rhodopsin (4-keto-BR) embedded in a polymer matrix were studied. The l ight-induced spectral changes were found to be similar to those for 4- keto-BR in suspension, but the duration of the photocycle is substanti ally longer (up to ten bf h). Application of a constant electric field induces a bathochromic shift of the main absorption band, the amplitu de of the field-induced spectral changes, showing a quadratic dependen ce on the field strength. Polymer films containing bacteriorhodopsin a nalogs show promise as new spectrally-selective photochromic and elect rochromic materials.