%0 Journal Article %J Nanoscale %D 2019 %T Nanographene oxide-TiO2 photonic films as plasmon-free substrates for surface-enhanced Raman scattering %A D. Papadakis %A Diamantopoulou, A. %A P.A. Pantazopoulos %A D. Palles %A E. Sakellis %A N. Boukos %A N. Stefanou %A V. Likodimos %X The development of nanostructured semiconductors with tailored morphology and electronic properties for surface-enhanced Raman scattering (SERS) has been attracting significant attention as a promising alternative to conventional coinage metal SERS substrates. In this work, functionalized TiO2 photonic crystals by graphene oxide nanocolloids (nanoGO) are demonstrated as highly sensitive, recyclable, plasmon-free SERS substrates that combine slow-photon amplification effects with the high adsorption capacity and surface reactivity of GO nanosheets. Comparative evaluation of photonic band gap engineered nanoGO-TiO2 inverse opal films was performed on methylene blue SERS detection under different laser excitations in combination with rigorous theoretical simulations of the photonic band structure. A very low detection limit of 6 × 10-7 M and an enhancement factor of 5 × 104 along with excellent self-cleaning performance and reusability could be achieved by the interplay of slow-photon effects assisted by interfacial charge transfer between the analyte and the nanoGO-TiO2 semiconducting substrate. Slow-photon management in combination with judicious engineering of chemical enhancement in photonic nanostructures is accordingly proposed as an advanced approach for the design of efficient dielectric SERS substrates. © 2019 The Royal Society of Chemistry. %B Nanoscale %V 11 %P 21542-21553 %G eng %U https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074965933&doi=10.1039%2fc9nr07680h&partnerID=40&md5=1e1c656e4551debd95f650d88ec88a87 %R 10.1039/c9nr07680h