Pulsed laser deposition of CuInS2 quantum dots on one-dimensional TiO2 nanorod arrays and their photoelectrochemical characteristics

• The CuInS2 QDs are deposited on TiO2 nanorods by PLD technique for the first time.
• The size of CuInS2 QD can be controlled by adjusting the laser energy.
• The photovoltaic device exhibits high stability in air.
• The CuInS2 QDSSCs obtained a high energy conversion efficiency of 3.95%.

In the typical solution-based synthesis of colloidal quantum dots (QDs), it always resorts to some surface treatment, ligand exchange processing or post-synthesis processing, which might involve some toxic chemical regents injurious to the performance of QD sensitized solar cells. In this work, the CuInS2 QDs are deposited on the surface of one-dimensional TiO2 nanorod arrays by the pulsed laser deposition (PLD) technique. The CuInS2 QDs are coated on TiO2 nanorods without any ligand engineering, and the performance of the obtained CuInS2 QD sensitized solar cells is optimized by adjusting the laser energy. An energy conversion efficiency of 3.95% is achieved under one sun illumination (AM 1.5, 100 mW cm−2). The improved performance is attributed to enhanced absorption in the longer wavelength region, quick interfacial charge transfer and few chance of carrier recombination with holes for CuInS2 QD-sensitized solar cells. Moreover, the photovoltaic device exhibits high stability in air without any specific encapsulation. Thus, the PLD technique could be further applied for the fabrication of QDs or other absorption materials.

The possible mechanism for the improved performance of CuInS2 quantum dots sensitized solar cells is that CuInS2 quantum dots could be easily excited and generate photoelectrons and holes. Electrons transfer to the conduction band of TiO2 and holes transport into the opposite direction. The higher conduction band edge of CuInS2 is advantageous to electron injection and hole recovery, which eventually enhances the energy conversion efficiency.Figure optionsDownload as PowerPoint slide