University of the Witwatersrand

START Co-Investigator: David Billing

START Post-Doc: Francis Otieno

Project: Use of synchrotron techniques to characterize Solid Oxide Fuel Cells thin films and ternary active layer of organic solar cell devices

The first part of the project involves the morphology and performance optimisation of organic ternary blend made of a single polymer (Donor) and fullerene and non-fullerene (Acceptor) mix with complimentary absorption. This will be characterized using different synchrotron techniques such as in situ GIWAXS, GISAXS etc.

The second part explores mixed conducting perovskites (ABO3) thin films containing rare and alkaline earth metals on the A‐site and a transition metal on the B‐site for use as cathodes for solid oxide fuel cells (SOFC). We aim to grow thin films and understand their electrochemical properties using synchrotron techniques.

  1. Francis Otieno, Mildred Airo, Eric G. Njoroge, Rudolph Erasmus, Theodore Ganetsos, Alexander Quandt and Daniel Wamwangi. Effect of implantation of Sm+ ions into RF sputtered ZnO thin film. AIP Advances 9, 045210 (2019).
  2. ii) Francis Otieno, Mildred Airo, Rudolph M. Erasmus, David G. Billing, Alexander Quandt, and Daniel Wamwangi. “Effect of thermal treatment on ZnO: Tb3+ nano-crystalline thin films and application for spectral conversion in inverted organic solar cells.” RSC Advances 8, no. 51 (2018): 29274-29282
  3. Francis Otieno, Mildred Airo, Rudolph M. Erasmus, David G. Billing, Alexander Quandt, and Daniel Wamwangi. “Structural and spectroscopic analysis of ex-situ annealed RF sputtered aluminium doped zinc oxide thin films.” Journal of Applied Physics 122.7 (2017): 075303
  4. Francis Otieno, Bridget Mutuma, Mildred Airo, Kamalakannan Ranganathan, Neil Coville and Daniel Wamwangi, “Enhancement of organic photovoltaic device performance via P3HT:PCBM solution heat treatment.” Thin Solid Films 625 (2017): 62-69
  5. Francis Otieno, Shumbula N Prince, Mildred Airo, Mlambo Mbuso, Nosipho Moloto, Rudolph Erasmus, Alex Quandt and Daniel Wamwangi. “Improved efficiency of organic solar cells using Au NPs incorporated into PEDOT:PSS buffer layer.” AIP Advances. 7.8 (2017): 085302
  6. Otieno, Francis, Mildred Airo, Kamalakannan Ranganathan, and Daniel Wamwangi. “Annealed silver-islands for enhanced optical absorption in organic solar cell.” Thin Solid Films 598 (2016): 177-183
  7. Airo, Mildred, Siziwe Gqoba, Francis Otieno, Makwena Justice Moloto, and Nosipho Moloto. “Structural modification and band-gap crossover in indium selenide nanosheets.” RSC Advances 6.47 (2016): 40777-40784
  8. Airo MA, Rodrigues R, Gqoba S, Ntholeng N, Otieno F, Moloto MJ, Greenshields MW, Hümmelgen IA, Moloto N. Colloidal InSe nanostructures: Effect of morphology on their chemical sensitivity to methanol and formaldehyde fumes. Sensors and Actuators B: Chemical. 2016 Nov 29;236:116-25
  9. F. Otieno, K. Kamalakan, D. Wamwangi, ’Enhancing light absorption and life-time stability of organic solar cells using pentacene encapsulation. Proceedings of SAIP2015 – ISBN: 978-0-620-70714-5
Francis Otieno operating the GXRD Bruker D8 Discover, 40kV, 100 mA at Wits school of Chemistry