Photoelectric and flexible poly(styrene- b-ethylene/butylene- b-styrene)-zinc porphyrin-graphene hybrid composite: synthesis, performance, and mechanism

Abstract

Stretchable and flexible photoelectric materials are highly desirable for the development of artificial intelligence products. However, it remains a challenge to fabricate a stable, processable, and cost-efficient material with both high photoelectric sensitivity and remarkable deformability. Herein, a new kind of photoelectric sensitive, highly stretchable and environmentally adaptive materials was developed through in situ synthesis and π-π conjugation design. Specifically, a photoelectric elastomer zinc porphyrin SEBS(Zn-PorSEBS) was synthesized by introducing porphyrin to SEBS chain via a one-pot method. Then, graphene/zinc porphyrin SEBS (G/Zn-PorSEBS) composites were obtained by combing the elastomer with graphene sheets through solution blending. Notably, the resultant flexible composites were capable of capturing light changes with illumination on or off, and the maximum photocurrent density reached 0.13 μA cm^-2. Moreover, the photoelectric composites exhibited a dramatic elongation (more than 1000%) and an excellent tensile strength about 20 MPa. This proposed strategy represents a general approach to manufacture photoelectric and flexible materials.

Fig. 1. (a) The synthesis processes of Zn-PorSEBS elastomer. (b) Fabrication of G/Zn-PorSEBS composites.

Fig. 2. (a) FT-IR spectra of SEBS, Cl-SEBS, ALSEBS and PorSEBS. (b–e) ¹H NMR spectra of SEBS, Cl-SEBS, ALSEBS and PorSEBS. (f) XPS spectra of PorSEBS and Zn-PorSEBS.

Fig. 3. (a) Typical stress–strain curves of Zn-PorSEBS and G/Zn-PorSEBS with different graphene content. Inset photos showing the high stretchability of the sample. (b–f) Pictures giving the different deformation process of G/Zn-PorSEBS composites.

Fig. 4. Photocurrent switching response at 5 s intervals in a 0.3 V 1 M NaOH aqueous solution under 500 W Xenon lamp illumination. (a) Photocurrent response of neat SEBS and Zn-PorSEBS elastomer with different porphyrin grafting ratio. (b–d) Photocurrent response of Zn-PorSEBS elastomer and G/Zn-PorSEBS with different graphene content at the same porphyrin grafting ratio. (e and f) Photographs giving the light on/light off process.

Fig. 5. (a) UV-vis spectra of Zn-PorSEBS matrix and G/Zn-PorSEBS composite. (b) Molecular orbital energy diagram of photo-induced electron transfer from porphyrin to graphene. (c) SEM and (d) EDS mapping images of G/Zn-PorSEBS composite.