Hierarchical nanostructuring of porous silicon with electrochemical and regenerative electroless etching

Research output: Contribution to journalArticlepeer-review


  • Ermei Mäkilä
  • Anne-mari Anton Willmore
  • Haibo Yu
  • Marianna Irri
  • Mark Aindow
  • Tambet Teesalu
  • Kurt W. Kolasinski
  • Jarno Salonen

Colleges, School and Institutes

External organisations

  • Turku University
  • University of Tartu
  • University of Connecticut
  • West Chester University


Hierarchically nanostructured silicon was produced by regenerative electroless etching (ReEtching) of Si powder made from pulverized anodized porous silicon. This material is characterized by ∼15 nm mesopores, into the walls of which tortuous 2–4 nm pores have been introduced. The walls are sufficiently narrow that they support quantum-confined crystallites that are photoluminescent. With suitable parameters, the ReEtching process also provides control over the emission color of the photoluminescence. Ball milling and hydrosilylation of this powder with undecylenic acid produces nanoparticles with hydrodynamic diameter of ∼220 nm that exhibit robust and bright luminescence that can be excited with either one ultraviolet/visible photon or two near-infrared photons. The long-lived, robust visible photoluminescence of these chemically passivated porous silicon nanoparticles is well-suited for bioimaging and theranostic applications.


Original languageEnglish
Pages (from-to)13056-13064
Number of pages9
JournalACS Nano
Issue number11
Early online date31 Oct 2019
Publication statusPublished - 26 Nov 2019


  • porous silicon, two-photon fluorescence, photoluminescence, etching, hierarchical nanostructure, nanoparticle