Photoelectric effects in insulating polymers and their relation to conduction processes

The photoelectric response of high polymers is different in four separate spectral regions. In the infrared, photocapacitive effects occur. In the near ultraviolet, there is injection of electrons and/or holes, with marked dependence upon the electrode material and strong time variations. In the far ultraviolet, interband excitation and photoemission experiments give estimates of band gap (9 eV) and work function (4 eV) which agree with other measurements of these quantities. In the gamma region there are immediate and delayed effects. Trapping of charge may be of importance in these materials, but it is difficult to obtain definitive evidence by optical means. Despite the differences between polymers, and between various samples of the same polymer, there are a surprising number of common features to the optical response.