Photocurrent characteristics of solution-processed mercury sulfide nanoparticles--thin films on plastic substrates

In this study, we synthesize mercury sulfide (HgS) nanoparticles (NPs) by the colloidal method and investigate the optoelectronic characteristics of the resulting HgS NPs-thin films on plastic substrates in air at room temperature. The HgS NPs with a size of about 6-nm show quantum confinement effects in the absorption and photoluminescence spectra of the HgS NPs-thin film. The flexible optoelectronic device is constructed with the HgS NPs-thin film on finger-pattered Au electrodes. When 325-nm wavelength light is irradiated on the HgS NPs-thin film, charge carriers are photogenerated and transported by the hopping mechanism, thereby giving birth to a photocurrent in the film. The photocurrent efficiency at a bias voltage of 5 V is estimated to be 1.6 microA/W x cm2 and the photocurrent efficiency in the 1000 cycles-bending test changes by less than one order of magnitude compared to its initial value before bending.