Graphenic carbon (GC) provides a potential ability as photovoltaic material due to its tunable properties. Here, we investigate the optical energy gap and the thickness of B-GC material as a p-type in solar cell application. The GC was prepared from old charcoal powders of coconut shells by heating process at 400°C and B-GC powders were prepared by wet mixing method using boric acid as B atom source. B-GC films were then prepared by employing nebulizer as a nanospraying method. All samples were examined through various characterization techniques such as X-Ray Diffarction (XRD), SEM cross section, and UVVis spectroscopy. The amorphous characteristic of B-GC is confirmed by broad peaks in XRD patterns, similar to that of reduced graphene oxide (rGO). The present of B along with O and dominant C elements is determined by SEM-EDX result. The B dopants affect the optical bandgap energy (Eg) of GC as an intrinsic material. The thickness of B-GC films was found to be thinner than in a previous study that used a similar method but different equipment. The average thickness of B-GC films is in the range of 127 to 420 nm, followed by an increase in the deposition time for 5 to 20 s. Estimation of the Eg value indicated that B-GC has an energy gap around 2 eV, which is most suitable as a window layer in solar cell applications.