Abstract: The present invention describes a method for the preparation of graphene or graphenic material films by the carbonization of biopolymers. The method comprises the following stages: preparation of an aqueous solution of a non-crystallizable water-soluble biopolymer or a derivative of said biopolymer at the suitable pH, coating of the substrate with the aqueous solution of the biopolymer prepared in the previous stage by immersion of the substrate in said solution or by using the spin coating technique, conditioning of the aqueous solution of the biopolymer by means of a hydrothermal process consisting of subjecting the coated surface to a flow of nitrogen saturated with water vapor at the temperature of between 100 and 250° C. for a time between 30 minutes and several hours, thermal decomposition of the biopolymer deposited on the substrate in the absence of oxygen at temperatures below 1200° C.

Abstract: Method for obtaining solid samples or suspensions of graphene optionally doped with heteroatoms from synthetic or natural polymers, which are subjected to pyrolysis in a furnace without oxygen at temperatures of between 400° C. and 1,200° C. and subsequently to a liquid-phase exfoliation phase. The polymers used are preferably polysaccharides, such as chitosan, alginate and alginic acid, which can be optionally doped with any heteroatom. The invention is intended primarily for use in microelectronics and photovoltaic devices in which graphene sheets are very useful. In addition, the graphene prepared cn be uses as an additive for polymers and ceramic materials.