3.4.2. Inhibition of *A. niger* Spores under Alternating Visible-Light Irradiation and Dark Conditions

The as-prepared samples, including the original bamboo, TB, AB-10, AB-30, ATB-5, ATB-10, ATB-30, and ATB-200 samples, were used for the antifungal test to inhibit *A. niger* spores under visible-light irradiation. The samples were tested under light radiation for 6 h every day, and then the light source was turned off. Figure 7 shows that the original bamboo and AB-10 samples were almost entirely covered with mycelia after incubation for five days, indicating poor resistance to *A. niger* under visible light. However, in addition to the original bamboo and AB-10, the TB and AB-30 samples also failed to inhibit the growth of *A. niger* after incubation for 28 days, even under visible-light irradiation. Optical images showed that their surfaces were almost entirely covered with mycelia (Figure 7(a1,c1)), indicating that they had no resistance to *A. niger*. Multiple fungal clusters were observed on the surface of ATB-5 after incubation for 28 days (Figure 7(b1), right). However, the ATB-10 and ATB-30 samples showed better antifungal activity than other samples, as *A. niger* mycelia failed to cover the entire surface of the samples after incubation for 28 days (Figure 7(d1,e1)). Note that ATB-200 exhibited better antifungal activity for *A. niger* under visible-light irradiation (Figure 7(f1), right) than under dark conditions (Figure 6(f1), left). This may be due to the plasmonic resonance effect of Ag metal under visible-light irradiation, inhibiting the growth of *A. niger* spores [39].
