Improving photodetector performance of PANI nanofiber by adding rare-earth La2O3 nanoparticles

Nanocomposites based on Polyaniline (PANI) nanofibers (NFs) and Lanthanum oxide (La2O3) nanoparticles (NPs) were successfully synthesized using hydrothermal and chemical methods, respectively. Thin films of pure PANI and PANI/La2O3 nanocomposites have been deposited by spin-coating technique on both n-Si and glass substrates. The prepared thin films have been tested using XRD, FE-SEM, and UV-Vis and were examined as photodetectors. The XRD pattern showed the crystalline nature of PANI NFs' film and the cubic structure of PANI/La2O3 films. FE-SEM images of pure PANI proved that the film prepared has a nanofiber-like structure, whereas the PANI/La2O3 nanocomposite films proved that La2O3 NPs capped with PANI NFs. The UV-Vis spectrum of pure PANI showed the absorption peaks of B and Q bands at 340 and 651 nm, while for PANI/La2O3 films, the position of the two bands shifted to 320 and 620 nm revealing a charge transfer between the PANI NFs and La2O3 NPs. The optical band gap value of PANI/La2O3 hybrid nanocomposite films decreases from 2.97 to 2.81 eV for B-band and from 1.49 to 1.43 eV for Q-band upon increasing the La2O3 content from 1 to 4 vol.% in the PANI NFs. On the other hand, incorporating La2O3 into PANI showed remarkably improved photodetector performance of the system. The maximum sensitivity values of the photoconductive detectors were observed for PANI/La2O3 nanocomposites deposited on an n-Si substrate which were approximately 342.72 and 5069.69% at 660 and 965 nm, respectively.

Automated summary

Nanocomposites of PANI nanofibers and La2O3 nanoparticles were synthesized and deposited as thin films. The structure and optical properties of the films were characterized, showing successful encapsulation of La2O3 by PANI NFs. The addition of La2O3 resulted in a decrease in the optical band gap and improved photodetector performance, with maximum sensitivity observed for films deposited on n-Si substrates.