LEWIS ACID MEDIATED FUNCTIONALIZATION OF POROUS SILICON WITH SUBSTITUTED ALKENES AND ALKYNES

Silicon surface chemistry is of fundamental importance because of the ubiquitous role of silicon in modern technology and yet is only just beginning to be investigated.1 Virtually all microprocessor chips in electronic products are based upon crystalline silicon wafers.2 Control of silicon surface chemistry is crucial to allow access to technologically interesting thin films for fabrication of new electronic devices.3 Canham and co-workers showed in 1990 that silicon wafers could be etched to produce a microns-thick porous layer (termed porous silicon) which exhibits photoluminescence upon exposure to UV light.4 Potential applications for porous silicon include use as chemical sensors,5 optoelectronic devices6 such as electroluminescent displays,7 photodetectors,8 and as a matrix for photopumped tunable lasers.9 As a result, modification and characterization of photoluminescent porous silicon surfaces has become an area of intense interest.10 In this work we report a mild and general approach for covalent modification of the surface of porous silicon through EtAlCl2 mediated hydrosilylation of readily available alkynes and alkenes which yields surface bound vinyl and alkyl groups, respectively, as outlined in eqs 1 and 2.11