N,N′-Bis(l-alanine tert-butylester)-3,4:9,10-perylene diimide molecule for volatile organic vapor detection

Abstract

Langmuir–Blodgett (LB) thin films were prepared using an N,N′-bis(L-alanine tert-butylester)-3,4:9,10-perylene diimide derivative to determine the optimum thin film forming conditions and their sensing properties towards volatile organic vapors. Our results showed that highly uniform LB films could be transferred onto gold substrates and were highly sensitive to dichloromethane and chloroform vapors with a high response and short recovery time. Structure–function relationships suggest that hydrogen bonding between the perylene diimide and the vapor molecules plays a significant role in determining the performance of perylene diimide sensing devices. Diffusion processes were investigated using Fick's second law. The diffusion of dichloromethane and chloroform vapors into the LB film structure yielded larger responses than other vapors. The interactions were reversible, and purging caused the vapor molecules to escape from the LB films.