Improved photon management in a photoelectrochemical cell with Nd-modified TiO2 thin film photoanode

Photon management involving particularly an up-conversion process is proposed as a relatively novel strategy for improving the efficiency of hydrogen generation in photoelectrochemical cells (PEC) with wide-band gap photoanodes. Optically active photoanode has been constructed by electrodeposition of titanium dioxide nanopowders containing Nd3+ ions, synthesized via a sol-gel method, onto ITO/TiO2(thin film) substrates. Thin films of TiO2 have been deposited by means of RF magnetron sputtering in an ultra-high-vacuum system. X-ray diffraction, scanning electron microscopy, UV-VIS-NIR spectrophotometry, and photoluminescence have been applied to assess the properties of photoanodes. In experiments involving photon-assisted water splitting, an external up-converter containing Yb3+/Er3+ rare-earth ions has been used. Photocurrent as a function of voltage (V-B) under illumination with white light is relatively high (280 mu A at V-B = 0 V) for pure TiO2 thin films and it is not affected by the electrodeposition of TiO2:Nd3+ powders. NIR-driven up-conversion with laser excitation at lambda = 980 nm has been found responsible for a 13-fold increase in photocurrent at V-B = 0 V in the modified PEC configuration. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.

Automated summary

Photon management involving up-conversion process is proposed to improve hydrogen generation efficiency in photoelectrochemical cells with wide-band gap photoanodes. Optically active photoanodes constructed with up-conversion technology show increased photocurrent output.