The Tauc equation was used to calculate the materials' optical band gap (Eg), and the corresponding graphs are provided in the supplementary information (Figure ). The band gap (Eg) values of ZIF-8, CPB NCs, and CPB/ZIF-8 were determined to be 5.34 eV, 2.32 eV, and 2.32 eV, respectively. The optical band gap analysis indicates no significant change between the CPB NCs and the CPB/ZIF-8 composite, confirming that the CPB NCs contribute significantly to the composite's optical activity.