Metal-Insulator-Semiconductor Anodes for Ultrastable and Site-Selective Upconversion Photoinduced Electrochemiluminescence

Photoinduced electrochemiluminescence (PECL) allows the electrochemically assisted conversion of low-energy photons into high-energy photons at an electrode surface. This concept is expected to have important implications, however, it is dramatically limited by the stability of the surface, impeding future developments. Here, a series of metal-insulator-semi-conductor (MIS) junctions, using photoactive n-type Si (n-Si) as a light absorber covered by a few-nanometer-thick protective SiOx/metal (SiOx/M, with M=Ru, Pt, and Ir) overlayers are investigated for upconversion PECL of the model co-reactant system involving the simultaneous oxidation of tris(bipyridine)ruthenium(II) and tri-n-propylamine. We show that n-Si/SiOx/Pt and n-Si/SiOx/Ir exhibit high photovoltages and record stabilities in operation (35 h for n-Si/SiOx/Ir) for the generation of intense PECL with an anti-Stokes shift of 218 nm. We also demonstrate that these surfaces can be employed for spatially localized PECL. These unprecedented performances are extremely promising for future applications of PECL.

Automated summary

This paper investigates the application of photoinduced electrochemiluminescence (PECL) in metal-insulator-semiconductor structures. By covering the surface of n-type silicon with a protective SiOx/metal layer, efficient PECL emission and spatial localization have been achieved. These findings are highly promising for future PECL applications.