Preparation of Polyimide/Zinc Oxide Nanocomposite Films via an Ion-Exchange Technique and Their Photoluminescence Properties

Figure 3

SEM images of the Zn²⁺-doped PI films after thermal treatment at 350°C for (a) 0, (b) 3, (c) 5, and (d) 7 h, respectively.

(a)

(b)

(c)

(d)