Boron-Doped Graphene Quantum Dots (BGQDs) from Spent Coffee Ground for Glucose Sensor

Figure 3

UV-vis absorption of (a) GQDs and (c) BGQDs prepared from SCG (200°C) and excitation-dependent PL behavior of (b) GQDs from 280 to 400 nm and (d) BGQDs from 280 to 430 nm. Inset photographs of GQDs solution in (a) and BGQDs solution in (c) were taken under visible and 365 nm UV light, respectively.

(a)

(b)

(c)

(d)