Electrogenerated Chemiluminescence: 34. Photo‐Induced Electrogenerated Chemiluminescence and Up‐Conversion at Semiconductor Electrodes

Abstract

Photosensitized oxidations or reductions at p‐ and n‐type normalGaAs and normalInP semiconductor electrodes of aromatic species in aprotic solvents leading to electrogenerated chemiluminescence (ECL) are described. The energy of the irradiating light equal to the bandgap energy of the semiconductor and the electrical energy input couple to produce excited states which eventually produce emission at shorter wavelengths. Intense ECL is observed by alternately generating radical cations and radical anions at an illuminated semiconductor electrode with smaller potential excursions than required on metal (platinum) electrodes.

Luminescence Amplification at BiVO4 Photoanodes by Photoinduced Electrochemiluminescence

“…Moreover, the system fundamentally differs from previous studies where FL was avoided by using an incident wavelength, l exc , higher than the absorption band (l exc > l abs ) of the ECL emitter. [14][15][16] Here, we show that anodic PECL of this system can be induced at a potential as low as À0.4 V to amplify the overall luminescence (i.e. FL + PECL) in a precise manner.…”

“…SC photoelectrochemistry and ECL) opens new possibilities, among which, a considerable decrease in the potential required for light emission and original light conversion schemes. This unique concept, referred to as photoinduced electrochemiluminescence (PECL), has been only demonstrated in a few studies . In PECL, ECL is induced at the surface of an illuminated SC photoelectrode and the incident wavelength that is used to excite the SC ( λ exc ) is converted by the ECL reaction into the emission wavelength ( λ em ).…”

“…A major challenge of PECL is to overcome the competing photocorrosion mechanisms, which particularly pronounced in aqueous electrolytes and degrade SC electrodes, preventing ECL emission . PECL has been so far reported for designing electrochemically assisted up‐conversion systems ( λ exc > λ em ) at Si and III–V SC photoelectrodes using organic luminophores dissolved in dried organic electrolytes, or, more recently, in water with the co‐reactant system Ru(bpy) 3 2+ /tri‐n‐propylamine. The latter example allowed light production at a potential of +0.5 V vs. Ag/AgCl (all the potentials of this study are reported vs. this reference electrode) which is much lower than the typical potentials >1 V typically required with conventional electrodes .…”

Luminescence Amplification at BiVO4 Photoanodes by Photoinduced Electrochemiluminescence

“…This unique concept, referred to as photoinduced electrochemiluminescence (PECL), has been only demonstrated in a few studies. [14][15][16] In PECL, ECL is induced at the surface of an illuminated SC photoelectrode and the incident wavelength that is used to excite the SC (l exc ) is converted by the ECL reaction into the emission wavelength (l em ). A major challenge of PECL is to overcome the competing photocorrosion mechanisms, which particularly pronounced in aqueous electrolytes and degrade SC electrodes, preventing ECL emission.…”

“…A major challenge of PECL is to overcome the competing photocorrosion mechanisms, which particularly pronounced in aqueous electrolytes and degrade SC electrodes, preventing ECL emission. [17] PECL has been so far reported for designing electrochemically assisted up-conversion systems (l exc > l em ) at Si and III-V SC photoelectrodes using organic luminophores dissolved in dried organic electrolytes, [14,15] or, more recently, in water with the co-reactant system Ru-(bpy) 3…”