He is best known for his seminal role in the development of polyelectrolyte multilayers, which is today known as “layer-by-layer (LbL) assembly”,[4] a simple yet powerful nanofabrication method that has enabled the development of entirely new technologies, such as biocompatible coatings on medical devices, ultrastrong nanocomposites, neural interfaces, charge-storage devices, gas separation, fire retardants, and gene delivery platforms.

[6] Decher's work on the self-assembly and buildup of multilayer films by alternating application of anionic and cationic components during the early 1990s[7] is generally credited for the revitalization of the layer-by-layer assembly technique and its current prevalence in nanoscience.

Prior to completing his Diploma thesis with Gernot Boche on the NMR spectroscopy of carbanions, he spent a year working with William Russey at Juniata College in Pennsylvania.

In 1986 he obtained his PhD in organic chemistry from Johannes Gutenberg University of Mainz, Germany, working in the laboratory of Helmut Ringsdorf on drug-carrying polymers and lyotropic liquid crystals.

From 1988 to 1994 Decher was an Assistant Professor with Helmuth Möhwald at Johannes Gutenberg University of Mainz, where he began his research on the development of layer-by-layer assembly as part of his Habilitation in physical chemistry.