Limiting regimes of MOF modified semiconductor Amol Kumar , Jingguo Li, Anna M. Beiler, and Sascha Ott Department of Chemistry – Ångström Laboratory, Uppsala University, Box 523, 75237 Uppsala, Sweden Metal-organic frameworks (MOFs) have shown great potential in supporting large photovoltages in photoelectrochemical (PEC) applications. Surface modification of semiconductors using MOFs can improve PEC performance by promoting efficient interfacial charge transfer. This hybrid photocathode takes advantage of semiconductors by harvesting solar energy to absorb photons and drive the redox reactions at a lower energetic cost, whereas MOF provides well-defined tunable active sites and long-term stability. Here we examine the photocurrent densities supplied by the MOF-modified system, with special emphasis on the limiting factors governing the activity of a surface-modified PEC construct. Typically, electroactive MOFs have low diffusion coefficients, on the order of 10 -8 to 10 -14 cm 2 s -1 , which can slow down the charge transport. Despite this, a catalytically active MOF can still support higher current densities by sweeping away the photogenerated charges into a final product, even if the diffusion remains slow. References 1. Beiler, A.M., McCarthy, B.D., Johnson, B.A., Ott, S. Enhancing photovoltages at p-type semiconductors through a redox- active metal-organic framework surface coating. Nat Commun 11 , 5819 (2020) 2. Roy, S.; Huang, Z.; Bhunia, A.; Castner, A.; Gupta, A. K.; Zou, X.; Ott, S. Electrocatalytic Hydrogen Evolution from a Cobaloxime-Based Metal–Organic Framework Thin Film. J. Am. Chem. Soc. 2019, 141 (40), 15942-15950.
P120
© The Author(s), 2025
Made with FlippingBook Learn more on our blog