A general method for the formation of a broad family of silicon nanotube arrays (Si NTAs) relevant to diverse fields--ranging from energy storage to therapeutic platforms--is described. Such nanotubes demonstrate a thickness-dependent dissolution behavior important to its potential use in drug delivery. Under selected conditions, novel porous silicon nanotubes can be prepared when the shell thickness is on the order of 12 nm or less, capable of being loaded with small molecules such as luminescent ruthenium dyes associated with dye-sensitized photovoltaic devices.