Improved Performance of CuInS₂ Quantum Dot-Sensitized Solar Cells Based on a Multilayered Architecture

Abstract

This article describes a CuInS2 quantum dot (QD)-sensitized solar cell (QDSSC) with a multilayered architecture and a cascaded energy-gap structure fabricated using a successive ionic-layer adsorption and reaction process. We initially used different metal chalcogenides as interfacial buffer layers to improve unmatched band alignments between the TiO2 and CuInS2 QD sensitizers. In this design, the photovoltaic performance, in terms of the short-circuit current density (JSC), open-circuit voltage (VOC), fill factor (FF), and power conversion efficiency (PCE), was significantly improved. Both JSC and VOC were improved in CuInS2-based QDSSCs in the presence of interfacial buffer layers because of proper band alignment across the heterointerface and the negative band edge movement of TiO2. The PCE of CuInS2-based QDSSCs containing In2Se3 interfacial buffer layers was 1.35%, with JSC=5.83 mA/cm2, VOC=595 mV, and FF=39.0%. We also examined the use of alternative CdS and CdSe hybrid-sensitized layers, which were sequentially deposited onto the In2Se3/CuInS2 configuration for creating favorable cascaded energy-gap structures. Both JSC (11.3 mA cm(-2)) and FF (47.3%) for the CuInS2/CdSe hybrid-sensitized cells were higher than those for CuInS2-based cells (JSC=5.83 mA cm(-2) and FF=39.0%). In addition, the hybrid-sensitized cells had PCEs that were 1.3 times those of cells containing identically pretreated In2Se3 interfacial buffer layers. Additionally, we determined that ZnSe served as a good passivation layer on the surface of CuInS2/CdSe hybrid-sensitized QDs, prevented current leakage from the QDs to electrolytes, and lowered interfacial charge recombination. Under simulated illumination (AM 1.5, 100 mW cm(-2)), multilayered QDSSCs with distinct architectures delivered a maximum external quantum efficiency of 80% at 500 nm and a maximum PCE of 4.55%, approximately 9 times that of QDSSCs fabricated with pristine CuInS2.

MoS2 Nanosheet‐Modified CuInS2 Photocatalyst for Visible‐Light‐Driven Hydrogen Production from Water

“…85-1575;I -42D), respectively. [43] It should be noticed that no typical diffractionp eaks of MoS 2 are observed in the XRD pattern of MoS 2 /CuInS 2 composites, which mayr esult from the low amounta nd relativelyl ow diffraction intensity of MoS 2 .T he presence of MoS 2 in the MoS 2 / CuInS 2 composites can be confirmed by the high-resolution TEM (HRTEM) and X-ray photoelectron spectroscopy (XPS) analyses, as discussed below.…”

“…As for the pure CuInS 2 sample, the typical diffraction peaks of CuInS 2 located at 2 θ =27.5°, 33.2°, 46.7°, and 54.8° are observed, which can be attributed to the (1 1 2), (2 0 0), (2 1 4), and (1 1 6) crystal planes of chalcopyrite‐type CuInS 2 (JCPDS card No. 85‐1575; I‐42D), respectively . It should be noticed that no typical diffraction peaks of MoS 2 are observed in the XRD pattern of MoS 2 /CuInS 2 composites, which may result from the low amount and relatively low diffraction intensity of MoS 2 .…”

Cu5FeS4 Nanoparticles With Tunable Plasmon Resonances for Efficient Photothermal Therapy of Cancers

“…In Figure 1D, it exhibited the high-resolution Cu 2p spectrum (red line) and Fe 2p spectrum (blue line) for the CFS nanoparticles. The binding energy peaks at 931.8 and 951.7 eV could belong to Cu (I) coordinated to Cu in CFS nanoparticles (Chang et al, 2013). Generally speaking, the existence of Cu(II) in copper-based photothermal agents could contribute to the defect structure, thus resulting in NIR absorption (Li et al, 2015).…”

Comparative advantages of Zn–Cu–In–S alloy QDs in the construction of quantum dot-sensitized solar cells

“…As for other surface passivation method, it is common to implement photoanode posttreatment by depositing ZnS layer over the sensitized electrode via successive ionic layer adsorption and reaction (SILAR) route to reduce the TiO 2 /QD/electrolyte interfaces charge recombination and consequently improve the photovoltaic performance of the cell devices. [23][24][25][26][27] However, the retardation of charge recombination based on SILAR route is less efficient because ZnS layer is deposited as a loose particle-packing network around the exposed surface of QD sensitizers and therefore cannot effectively minimize the intrinsic defects inside QDs. Meanwhile, the post-deposited ZnS layer by SILAR route cannot serve as an energetic barrier layer at TiO 2 /QD interface to reduce the charge recombination at these interfaces.…”