On the photoconductivity behavior of emeraldine-salt polyaniline films

Deep and shallow traps play a fundamental role in the photoresponse profile of organic devices. Here we present an investigation on emeraldine-salt polyaniline films concerning structural, optical, and electrical properties by X-rays diffraction, optical and electron microscopies, and optical spectroscopies as Fourier Transform Infrared Spectroscopy (FTIR), absorption, and photoluminescence (PL). Photoconductivity measurements show signatures related to localized states near-edge absorption and the efficient transition between polaron bands. The photoconductive profile is dependent on the excitation intensity and presents negative photoconductivity (NPC) for higher intensities. A rate equations model attributes the NPC to shallow traps while the increase of response and recovery times are associated with deep traps.

Automated summary

The study demonstrates the important role of deep and shallow traps in the photoresponse profile of organic devices. The photoconductive profile depends on excitation intensity and shows negative photoconductivity for higher intensities.