Significance of defect engineering and hetero-junction engineering to improve the photoelectrochemical properties of ZnO nanorods photoanode
The significance of defect engineering in tuning the visible light driven photoelectrochemical properties due to alkali metal (Li, Na, K) doping into ZnO nanorods (NRs) photoanode is investigated. Large concentration of oxygen-vacancies introduced because of alkali doping serve as the light absorbing donor sites and also photoelectron recombination centres resulting enhanced photocurrent and hole separation in the valance band, respectively. The lattice strain developed in the nanorods due to doping contributes in easy electron transportation and mobility. Defect engineering also tunes the electronic structure of the photoanodes boosting charge carrier migration and reduced electron-hole pair recombination resulting enhanced oxygen evolution reaction. On the other hand, the design of multidimensional nano-heterostructures based photoelectrode is demonstrated by coupling the multilayered two-dimensional (2D) structure of MoS2 and MoO3 on the well aligned arrays of one-dimensional (1D) ZnO nanorods template expecting the effective synergic effects. The advantages of catalytically active sites of 2D layered structure of transition metal dichalcogenides/oxides is integrated with the distinctive dimensionality dependent phenomena of 1D structure to achieve enormous surface area for light harvesting and photoelectrochemical reaction along with favorable photocarrier dynamics required for water splitting.
K. Karmakar, A. Sarkar, K. Mandal and G. G.Khan. Investigating the role of oxygen vacancies and lattice strain defects on enhanced photoelectrochemical property of alkali metal (Li, Na and K) doped ZnO nanorods photoanodes. ChemElectroChem 2018, 5, 1147 –1152.
K. Karmakar, D. Maity, D. Pal, G. G. Khan and K. Mandal. Photo-induced Exciton Dynamics and Broadband Light Harvesting in ZnO Nanorod Templated Multilayered 2D MoS2/MoO3 Photoanodes for Solar Fuel Generation. (Under Review)