Flexible and efficient ultraviolet photodetectors based on one dimensional MWCNT filled thermoplastic polyurethane nanocomposite freestanding films

Abstract

Flexible ultraviolet (UV) photodetectors have attracted attention for many applications. Thermoplastic polyurethane (TPU) matrix nanocomposites have been prepared via solution mixing method with varying wt.% (0.1, 0.3, 0.5, and 1.0 wt.%) of MWCNTs. Surface morphology of MWCNTs/TPU nanocomposite films with 0.1 wt.% to 1.0 wt.% have been studied using scanning electron microscopy (SEM), which show the uniform dispersion of MWCNTs in TPU matrix, and coating of TPU on the surface of MWCNTs. UV photodetection performance and its mechanism of these MWCNTs/TPU nanocomposite films have also been studies. It was found that the highest responsivity of 1.710 A/W, and highest EQE of 579.84% is found for the device made from PUCNT1.0 sample. The detectivity of all the devices made from MWCNTs/TPU nanocomposite films have also been measured, which suggests that the highest detectivity of 8.09×10¹¹ Jones was observed for the device made from PUCNT1.0 sample. As the concentration of the MWCNT increases in the TPU matrix, the detectivity increases. These results provide us the clear guidelines to prepare the MWCNTs filled TPU nanocomposites for making free standing, flexible, and efficient UV photo-detecting devices.