Functional two-dimensional nanoarchitectures based on chemically converted graphene oxide and hematoporphyrin under the sulfuric acid treatment

• A covalent functionalization of graphene oxide is proposed.
• A novel graphene oxide hybrid material was created.
• A stable pH HP/GO nanocomposite has been obtained.
• An esterification reaction was catalyzed by sulfuric acid.

A model photosensitizer, hematoporphyrin (HP), captured by graphene oxide (GO) nanocarrier with and without the treatment by sulfuric acid was investigated for UV–VIS absorption, luminescence properties and Raman scattering. We demonstrate that combination of optical techniques can be efficiently used to detect an interfacial structure of hematoporphyrine/graphene oxide (HP/GO) nanoensembles. Finally, stable in aqueous media at neutral pH HP/GO nanocomposite were obtained as a result of esterification reaction catalyzed by sulfuric acid. The nanocomposite with stronger absorption and emission represents a layered structure composed of hematoporphyrine oligomers adsorbed on the surface of GO in monolayer through electrostatic and π-stacking interactions. The formation of such hybrid structures, where graphene oxide plays a role of a non-toxic sheet-like nanocarrier, open the way to create a functional nanocomposites with a high level of selective emission and efficient photosensitizing ability utilizing unique graphene properties as singlet oxygen generation enhancer.

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