Novel Integration of Nickel Phthalocyanine/Nickel Oxide-Based Photocathodes and Copper-Encapsulated Carbon-Dot-Cosensitized Photoanodes in Tandem for a Highly Efficient Solar Cell

Abstract

A notable strategy to achieve a dramatically high power conversion efficiency (PCE) of 9.76% for a tandem photovoltaic device has been implemented by the use of a nickel phthalocyanine-tetrasulfonic acid tetrasodium salt (NiPcTs) dye-sensitized p-type nickel oxide (NiO) semiconductor-based photocathode supported over carbon (C)-fabric paired with a photoanode scaffold comprising luminescent and conducting core/shell copper@carbon dots (Cu@C-dots) anchored to cadmium sulfide (CdS) quantum dots tethered to n-type titanium oxide (TiO2). The PCE yielded for the n-type quantum dot-sensitized solar cell (n-QDSC) or photoanode-based half-cell (TiO2/CdS/Cu@C-dots-nS2–/S n 2–-C-fabric) is 6.82% with a significant contribution from the light-harvesting capability of the plasmonic Cu core encased within the C-dot shell. In spite of the long-wavelength light-harvesting NiPcTs enabling easier reduction of the polysulfide electrolyte because of the additional photoexcited charge transfer, the p-type solar cell (p-SC) or photocathode-based half-cell (NiO/NiPcTs-nS2–/S n 2–-C-fabric) delivers a relatively lower PCE of 0.039%, but on coassembling the p- and n-half solar cells in a tandem design (TiO2/CdS/Cu@C-dots-nS2–/S n 2–-NiPcTs/NiO/C-fabric) the cell efficiency gets an immense boost under 1 sun illumination in consequence of the maximized range of light absorption afforded by CdS–Cu@C-dots on one side and NiPcTs on the other. This work rationalizes the synergism between the photoanode and photocathode elaborately to obtain a hitherto unmatched solar energy conversion in tandem solar cells.

Dye-sensitized solar cells strike back

“…Deepa et al reported the most efficient tandem cell to date at 9.76% for a device which included a photocathode with a nickel pthalocyanine dye (NiPcTs) on NiO supported over carbon fabric. 733 The photoanode was assembled from conducting core/shell copper@carbon dots anchored to CdS quantum dots on TiO 2 and a polysulfide electrolyte was used for compatibility with the CdS. The efficiency of the photocathode half-cell was quite low (0.039%) but when incorporated into the hybrid tandem device it improved the efficiency by almost 3% compared to the photoanode device with carbon fabric alone as the counter electrode (6.69%).…”

Manifestation of the Enhanced Photovoltaic Performance in Eco-Friendly AgBiS2 Solar Cells Using Titanium Oxynitride as the Electron Transport Layer

“…The MS curve is fitted using eq 1 C 2 = 2 ε 0 ε A 2 e N normald ( V app − V fb − K B T e ) where C denotes the differential capacitance of the space-charge region, ε denotes the dielectric constant of the material, ε 0 denotes the permittivity of free space, A denotes the active area, e denotes the charge of the electron, N d denotes the electron density, V app denotes the applied voltage, K B denotes the Boltzmann constant, and T denotes the temperature. The flat-band potential represents the potential that emerged as a result of the charge accumulation or depletion in a semiconductor, and therefore, it will not lead to any band bending at the interface region . The fitting parameters show a more negative flat-band potential of −1.24 V for TiON than TiO 2 , which is −1.1 V. Further, the positive slopes of tangent lines in the linear part of the curves represent the n-type behavior of the systems.…”

Carbon-Based Quantum Dots for Photovoltaic Devices: A Review

“…Kolay et al. synthesized Cu/CQDs core/shell nanocomposites as modifications to the TiO 2 /CdS photocathode of a solar cell . Glucose was hydrothermally reacted in a copper NO 3 solution, yielding Cu/CQDs comprising 20–60 nm Cu cores with uniform 5 nm thick graphitic CQDs coatings.…”

“…Kolay et al synthesized Cu/CQDs core/shell nanocomposites as modifications to the TiO 2 /CdS photocathode of a solar cell. 61 Glucose was hydrothermally reacted in a copper NO 3 solution, yielding Cu/CQDs comprising 20−60 nm Cu cores with uniform 5 nm thick graphitic CQDs coatings. The Cu nanocores exhibited localized surface plasmon resonance, which concentrated the incident photons for increased electron−hole pair formation and reduced recombination.…”