Charge transfer assisted nonlinear optical and photoconductive properties of CdS-AgInS2 nanocrystals grown in semiconducting polymers

Abstract

Anisotropic CdS-AgInS2 nanocrystals are directly grown into benzothiadiazole-based semiconducting polymer solution. Their nonlinear optical absorption and nonlinear scattering are investigated with 7-ns laser pulses of 532-nm wavelength for optical limiting applications. Optical limiting is found to be enhanced in the polymer-CdS-AgInS2 nanocomposites, as compared to pure polymer or CdS-AgInS2 nanocrystals. The observation is explained quantitatively using a numerical model which includes one-photon-induced excited state absorption, two-photon absorption, and nonlinear scattering. Presence of charge transfer in polymer-CdS-AgInS 2 nanocomposites is found from zero-biased photoconduction experiments, which plays an important role in the enhancement of nonlinear optical properties. In addition, it is also demonstrated that these nanocomposite films can be utilized for photodetection with large and fast photoconductive responses. © 2013 American Institute of Physics.