TY - JOUR
T1 - Chalcopyrite CuIn(S1- xSex)2 for Photoelectrocatalytic H2 Evolution
T2 - Unraveling the Energetics and Complex Kinetics of Photogenerated Charge Transfer in the Semiconductor Bulk
AU - Frick, Jessica J.
AU - Cava, Robert Joseph
AU - Bocarsly, Andrew Bruce
N1 - Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/7/10
Y1 - 2018/7/10
N2 - Cu(In,Ga)(S,Se)2 (CIGS) chalcopyrites and their derivatives are potential candidates for use in photoelectrochemical (PEC) H2 generation because of their well-matched solar absorption properties and agreeable band positions relative to the water reduction redox potential. In this work, we present the photoelectrochemical characterization and H2 evolution performance of the highly tunable anion CIGS derivative series CuIn(S1-xSex)2. The photocathodes were subjected to Mott-Schottky analysis and chopped-light irradiation to determine their flat band potential. With excellent agreement between the two techniques, the flat band potentials were determined to increase successively with increasing x in CuIn(S1-xSex)2, with all band positions possessing appropriate energetics for the thermodynamic requirement of reducing H2O to H2. The photocathodes were then subjected to identical bulk H2 evolution conditions for 10-12 h, maintaining ∼90% faradaic efficiency. The rates of photoelectrocatalysis were found to vary significantly within the CuIn(S1-xSex)2 series, ranging over 2 orders of magnitude using a constant light intensity of 100 mW/cm2. Carrier transport behavior beyond the space charge region where charge diffusion dominates is suggested as a limiting factor for the H2 evolution rate of these p-type materials through the indirect influence of the majority carrier concentration.
AB - Cu(In,Ga)(S,Se)2 (CIGS) chalcopyrites and their derivatives are potential candidates for use in photoelectrochemical (PEC) H2 generation because of their well-matched solar absorption properties and agreeable band positions relative to the water reduction redox potential. In this work, we present the photoelectrochemical characterization and H2 evolution performance of the highly tunable anion CIGS derivative series CuIn(S1-xSex)2. The photocathodes were subjected to Mott-Schottky analysis and chopped-light irradiation to determine their flat band potential. With excellent agreement between the two techniques, the flat band potentials were determined to increase successively with increasing x in CuIn(S1-xSex)2, with all band positions possessing appropriate energetics for the thermodynamic requirement of reducing H2O to H2. The photocathodes were then subjected to identical bulk H2 evolution conditions for 10-12 h, maintaining ∼90% faradaic efficiency. The rates of photoelectrocatalysis were found to vary significantly within the CuIn(S1-xSex)2 series, ranging over 2 orders of magnitude using a constant light intensity of 100 mW/cm2. Carrier transport behavior beyond the space charge region where charge diffusion dominates is suggested as a limiting factor for the H2 evolution rate of these p-type materials through the indirect influence of the majority carrier concentration.
UR - http://www.scopus.com/inward/record.url?scp=85048705465&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85048705465&partnerID=8YFLogxK
U2 - 10.1021/acs.chemmater.8b01827
DO - 10.1021/acs.chemmater.8b01827
M3 - Article
AN - SCOPUS:85048705465
SN - 0897-4756
VL - 30
SP - 4422
EP - 4431
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 13
ER -