Gradient doping – a case study with Ti-Fe2O3 towards an improved photoelectrochemical response. Issue 48 (23rd November 2016)

• Record Type: Journal Article
• Authors: Srivastav, Anupam; Verma, Anuradha; Banerjee, Anamika; Khan, Saif A.; Gupta, Mukul; Satsangi, Vibha Rani; Shrivastav, Rohit; Dass, Sahab
• Is Part Of: Physical chemistry chemical physics. Volume 18:Issue 48(2016)
• Page Start: 32735
• Page End: 32743
• Publication Date: 2016-11-23
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c6cp05515j
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The effect of gradient doping on modifying the photoelectrochemical response of Ti-doped Fe2 O3 photoanodes for their use in sunlight based water splitting for hydrogen evolution is investigated. Abstract : The present study investigates the effect of gradient doping on modifying the photoelectrochemical response of Ti-doped Fe2 O3 photoanodes for their use in sunlight based water splitting for hydrogen evolution. The deposition of a thin film over the ITO (tin doped indium oxide) substrate was carried out using a spray pyrolysis method. The concentration of dopant was varied from 0.5–8.0 at% and two sets of samples were also prepared with low to high (0.5–8%) and high to low (8–0.5%) dopant concentrations in the direction towards the substrate. The prepared thin films were characterized using X-ray Diffractometry (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) Spectroscopy, Secondary Ion Mass Spectroscopy (SIMS), X-ray Photoelectron Spectroscopy (XPS) and UV-visible Spectroscopy. The photoelectrochemical studies revealed that the deposition of dopant layers with a low to high concentration towards the substrate exhibited a highly improved photoresponse (200 times) in comparison to the pristine sample and a two fold enhancement in comparison to 2% Ti-doped Fe2 O3 . The improvement in the photoresponse has been attributed to the values of a high flat band potential, low resistance, high open circuit voltage, carrier separation efficiency, applied bias photon-to-current conversion efficiency (ABPE), and incident photon-to-current conversion efficiency (IPCE). A reduced charge transfer resistance has been demonstrated with Nyquist plots.