Tuning of Interfacial Charge Transport in Organic Heterostructures via Aryl Electrografting for Efficient Gas Sensors.

Fiche publication

Date publication

janvier 2024

Journal

ACS applied materials & interfaces

Auteurs

Membres identifiés du Cancéropôle Est :
Pr LESNIEWSKA Eric

Tous les auteurs :
Kumar A, Nwosu ID, Meunier-Prest R, Lesniewska E, Bouvet M

Lien Pubmed

https://www.ncbi.nlm.nih.gov/pubmed/38224467

Résumé

Modulation of interfacial conductivity in organic heterostructures is a highly promising strategy to improve the performance of electronic devices. In this endeavor, the present work reports the fabrication of a bilayer heterojunction device, combining octafluoro copper phthalocyanine (CuFPc) and lutetium bis-phthalocyanine (LuPc) and tunes the charge transport at the Cu(FPc)-(LuPc) interface by aryl electrografting on the device electrode to improve the device NH-sensing properties. Dimethoxybenzene (DMB) and tetrafluoro benzene (TFB) electrografted by an aryldiazonium electroreduction method form a few-nanometer-thick organic film on ITO. The conductivity of the heterojunction devices formed by coating a Cu(FPc)/LuPc bilayer over the aryl-grafted electrode strongly varies according to the electronic effects of the substituents in the aryl. Accordingly, DMB increases while TFB decreases the mobile charges accumulation at the Cu(FPc)-(LuPc) interface. This is explained by the perfect alignment of the frontier molecular orbitals of DMB and Cu(FPc), facilitating charge injection into the Cu(FPc) layer. On the contrary, TFB behaves like a strong acceptor and reduces the mobile charges accumulation at the Cu(FPc)-(LuPc) interface. Such interfacial conductivity variation influences the device NH-sensing properties, which increase because of DMB grafting and decrease in the presence of TFB. DMB-based heterojunction devices contain four times higher active sites for NH adsorption and could detect NH down to 1 ppm with limited interference from humidity, making them suitable for real environment NH detection.