Semiempirical modeling of a three sublayer photoanode for highly efficient photoelectrochemical water splitting: Parameter and electrolyte optimizations
By Ristova, Mimoza M.; Zhu, Wei; Yu, Kin Man; Walukiewicz, Wladyslaw
Published in Solar Energy Materials and Solar Cells
NULL
2016
Abstract
Abstract Below we present semiempirical modeling of conceptually new three-sublayer photoanode, composed of Absorber, Grading and Barrier sublayers, for highly efficient photoelectrochemical water dissociation. The modeling resulted into Absorber (Sub-A) made of Cd0.55Zn0.45O due to its favorable positions of the band extrema to the water splitting potentials and a band gap 2.0 eV. The Grading layer (Sub-G) was composed of CdxZn1?xO with a gradual decrease of x across the profile, changing from 0.2 to 0.55, aiming to photon absorption from 2.0 to 3.0 eV. At the same time, Sub-G furnishes the profile with an implanted electrical field that improves the hole-transport. The electron Barrier layer (Sub-B) deposited above the Sub-A, was engineered to provide 1 eV high barrier in the conduction band. It comprised of a 50 nm thick Ni0.4Cd0.6O film with Eg 3.0 eV with a valence band aligned to the one of the Sub-A, providing a barrier-free hole-flow. In this paper, we provide evidence that the proposed three-sublayer concept clearly represents a new paradigm for an improved efficiency for photocatalytic water dissociation. The highest photocatalytic activity of the optimized profile was achieved with an optimized electrolyte: 87% 1 M {K2HPO4} and 13% 1 M Na2SO3 (known to act as a hole scavenger or sacrificial agent) at pH=10. A noteworthy feature of this study is that under optimized profile parameters and customized electrolyte conditions the photocurrent yields increased from 0.05 mA/cm2 to 20 mA/cm2 at +1.2 V for visible light. The observed Incident Photon-to-Current Efficiency (IPCE) was about 50% measured at a photon energy of 3 eV.
Microsoft is Ending Support for Windows 7
Microsoft will discontinue support for Windows 7 on January 14, 2020 which means Gamry will also be discontinuing support for Windows 7. If you are upgrading to Windows 10, like many companies and institutions, you need to be running Version 7 of our s oftware . Please note that only USB and Ethernet-based instruments can run in Version 7. Eligible users can download the latest version of our software through our online Client Portal .
If you haven't already registered your instrument, you can do so through the Client Portal .
Please email Technical Support if you have any questions regarding this transition. Please be sure to include your instrument model and serial number when contacting us.