Tunning of Optoelectronic Properties in Nanohybrids of Peptide-Appended Perylenebisimides and Carbon Nanodots

Abstract

Two hybrid materials based on carbon dots (C-dots) and two perylenebisimide (PBI)-linked peptides with different functionality have been fabricated. These hybrids are designed to facilitate the electronic interaction between the electron donor C-dots and acceptor PBI-appended peptides, and the optoelectronic properties of these nanohybrids are compared. Amazingly, it is observed that the C-dots have exhibited favorable interactions with the PBI molecule (P1) bearing a similar charge (both negative) and have not shown any electronic interaction with the PBI molecule having opposite charges at their termini (P2). The pH of the medium has been found to be the limiting factor that has inhibited the electronic interaction between C-dots and P2. The interaction between C-dots and P1 has been attributed to the noncovalent complex formation. UV–visible and fluorescence spectroscopic study, field emission gun transmission electron microscopy, and time-correlated single-photon counting studies are made for this purpose. This nanohybrid material shows the emergence of good photoswitching behavior with the highest photocurrent gain of 5.14 (Iₒₙ/Iₒff) compared to that of only P1 or C-dots. The increase in the photoswitching property is attributed to efficient charge (electron–hole) separation and holds a future promise for fabricating a new nanohybrid material with a high photocurrent conversion efficiency.