Solid-State Succinonitrile/Sulfide Hole Transport Layer and Carbon Fabric Counter Electrode for a Quantum Dot Solar Cell

Abstract

A solid-state quantum dot solar cell (QDSC) is implemented with cadmium sulfide (CdS) quantum dots (QDs) tethered to titanium oxide (TiO 2 ) as photoanode, carbon fabric (C-fabric) as counter electrode (CE), and a solid electrolyte of succinonitrile/Na 2 S mixed in a 2:1 molar ratio (SN/S 2− ) as the hole transport material. Electron transfer and recombination processes are investigated by intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS) for a TiO 2 /CdS/ZnS-SN/S 2− -C-fabric (solid state) and TiO 2 /CdS/ZnS-S 2− -C-fabric (liquid junction) devices at different white light intensities. IMPS and IMVS studies show that the electron transport rate and electron recombination decrease with an increase in the intensity of light. The champion cell with a TiO 2 /CdS/ZnS photoanode and C-fabric as CE delivers a power conversion efficiency (PCE) of 5.2% with a solid electrolyte of SN/S 2− , and a PCE of 6.3% is obtained with the liquid aqueous electrolyte of 0.1 M Na 2 S. The effects of temperature on solar cell performance and the thermal dependence of ionic conductivity for the solid electrolyte are studied in detail. This study shows that the succinonitrile based solid electrolyte is a good substitute for the traditional liquid electrolyte.

Review of recent progress in the development of electrolytes for Cd/Pb-based quantum dot-sensitized solar cells: performance and stability

“…Kokal, Ramesh K. et al developed a solid-state electrolyte based on succinonitrile/Na 2 S for a CdS QDSSC with a maximum PCE of 6.3%, V oc of 753 V, J sc of 13 mA cm −2 , and FF of 61. 88 According to their work, solid-state electrolytes have increased thermal, electrical, and ionic conductivity. Raising the electrolyte temperature increases the electron density and electron mobility.…”

Quantum Dots and Their Applications: What Lies Ahead?

“…Devices for photovoltaics have long incorporated nanomaterials in order to boost the energy conversion efficiency . Nevertheless, new strategies to accomplish that goal have been reported, including those involving CdS QDs and CdSe and CdSe/CdS core–shell QDs . Also, new methods for capping PbS QDs with atomic ligands and improving passivation of CdSe/CdS/ZnS core–shell–shell QDs thin films have been described .…”

Quantum dots for temperature sensing.

“…The synthesis procedures as well as the energy structure determining absorption and Pl mechanisms in II-VI QDs are well developed and understood [6][7][8][9], therefore these NPs are already used as a good down-conversion material of LEDs [10], photodetectors [11], catalysts [12], in photovoltaics [13] and bioimaging [14]. However, the heavy metals included in their composition concern one about carcinogenicity and other chronic health risks, as well as disposal hazards.…”