Study of the back recombination processes of PbS quantum dots sensitized solar cells

• Published in: Superlattices and microstructures 2016-12, Vol.100, p.694-702
• Main Authors: Badawi, Ali, Al-Hosiny, N., Merazga, Amar, Albaradi, Ateyyah M., Abdallah, S., Talaat, H.
• Format: Article
• Language: English
• Subjects: Back recombination process; Quantum dots sensitized solar cell; SILAR; Time constant
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1016/j.spmi.2016.10.029

In this study, the back recombination processes of PbS quantum dots sensitized solar cells (QDSSCs) has been investigated. PbS QDs were adsorbed onto titania electrodes to act the role of sensitizers using successive ionic layer adsorption and reaction (SILAR) technique. The energy band gaps of the synthesized PbS QDs/titania are ranged from 1.64 eV (corresponding to 756 nm) to 3.12 eV (397 nm) matching the whole visible solar spectrum. The hyperbolic band model (HBM) was used to calculate PbS QDs size and it ranges from 1.76 to 3.44 nm. The photovoltaic parameters (open circuit voltage Voc, short circuit current density Jsc, fill factor FF and efficiency η) of the assembled PbS QDs sensitized solar cells (QDSSCs) were determined under a solar illumination of 100 mW/cm2 (AM 1.5 conditions). The open circuit voltage-decay (OCVD) rates of the assembled PbS QDSSCs were measured. The time constant (τ) for PbS QDSSCs (4 SILAR cycles) shows one order of magnitude larger than that of PbS QDSSCs (8 SILAR cycles) as a result of a decreased electron-hole back recombination. •Back recombination rates in PbS QDSSCs (4 cycles) is slower than those for 8 cycles.•The open circuit voltage-decay rates of PbS QDSSCs have been investigated.•Harvesting the visible solar spectrum by tuning the band gap of PbS QDs is studied.