Solar Cells

Increasing demands for energy and environmental concern have caused many researchers to look to alternative sources of energy. Solar energy has been a main area of focus as this energy is highly abundant and has the potential to solve the problem. Many solar farms today use silicon based solar panels, but these types of solar panels are costly both energetically and financially. Inorganic thin film light absorbing layers, such as CuInGaSe2 (CIGS), CuInS2 (CIS) and Cu2 ZnSnS4 (CZTS) are showing great promise as a replacement. These are CIGS based layers with the Ga removed (CIS) or the In from CIS replaced with Zn and Sn. They have reported lab efficiencies of around 10%. The drawback of these two materials is the high temperature annealation in sulfur atmosphere needed to achieve the high efficiency cells. We are trying to overcome this barrier with a one-pot, annealation free synthesis of the CIS and CZTS layers. A photoelectrochemical (PEC) measurement is performed on the material so the starting stoichiometry can be optimized to give the material with the largest photocurrent density. Further characterization is utilized to investigate their morphology (SEM and TEM), composition (XRF,XPS, EDX, HRTEM), structure (XRD, HRTEM), optical properties (UV- Vis, action spectra) and the kinetics of the photoreaction (PEC IMPS). After optimization, different methods of depositing not only the light-absorbing layer but also the other layers that compose a full solar device will be tested layer-by-layer. These methods include printing techniques, electrophoretic deposition and chemical bath deposition.

CZTS shows the most promise as a new absorbing layer. It is composed of earth abundant low cost element and if it can be synthesized in a way that is scalable, environmentally friendly, relatively cheap with comparable efficiencies to the current solar options it may be a solution to the energy crisis.

  1. Harati, M.; Love, D.; Lau, L. W. M.; Ding, Z., Prep of Crystall Zinc Oxide Films by One-step Electrodep in Reline. Mater Lett 2012, 89 (0), 339-342.
  2. Tapley, A.; Vaccarello, D.; Hedges, J.; Jia, F.; Love, D. A.; Ding, Z., Prep & Charact of CuInS2 NCs for Light-absorbing in Solar Cells. Phys Chem Chem Phys 2012, DOI:10.1039/C2CP42753B.
  3. Harati, M.; Jia, J.; Giffard, K.; Pellarin, K.; Hewson, C.; Love, D. A.; Lau, W. M.; Ding, Z., One-pot electrodeposition, characterization & photoactivity of CIGS thin films for solar cells. Phys Chem Chem Phys 2010, 12 (46), 15282-15290.