Enhancing Quantum Dot Solar Cells Stability with a Semiconducting Single‐Walled Carbon Nanotubes Interlayer Below the Top Anode

Abstract

Semiconducting single‐walled carbon nanotubes (s‐SWNTs) are used as a protective interlayer between the lead sulfide colloidal quantum dot (PbS CQD) active layer and the anode of the solar cells (SCs). The introduction of the carbon nanotubes leads to increased device stability, with 85% of the initial performance retained after 100 h exposure to simulated solar light in ambient condition. This is in sharp contrast with the behavior of the device without s‐SWNTs, for which the photoconversion efficiency, the open circuit voltage, the short‐circuit current, and the fill factor all experiencing a sharp decrease. Therefore, the inclusion of s‐SWNT as interlayer in CQD SCs, give rise to SCs of identical efficiency (above 8.5%) and prevents their performance degradation.

Stability of Quantum Dot Solar Cells: A Matter of (Life)Time

“…Efforts to replace the EDT layer have been made through choosing different ligands or introducing an additional layer. [73][74][75][76] For example, inserting an ultrathin NiO layer between the EDT and the gold electrodes strongly enhances the stability of the solar cells, which maintain 95% of their initial performance after heating to 80 °C for 2 h. [77] Alternatively, one can reduce the number of access sites for oxygen absorption by using a different size of PbS QDs in the EDT layer versus the PbX active layer. [78] A particularly promising route to replace EDT was recently suggested by Biondi et al, who used malonic acid instead of EDT, leading to an increase in the photovoltaic performance and device stability.…”

Functionalized rGO Interlayers Improve the Fill Factor and Current Density in PbS QDs-Based Solar Cells

“…As seen from Figure 5a, the density of states in the region of 0.30-0.35 eV is much lower for both devices with f-rGO. It is known that rGO [17] and other allotropic forms of carbon [38] increase the stability of photovoltaic devices with employed architecture due to the protection from atmospheric moisture. This correlates with our results because the devices were fabricated and measured in ambient conditions.…”

Recent Advances in Applications of Sorted Single‐Walled Carbon Nanotubes

“…In this context, the use of carbonaceous materials such as carbon paste and graphene have been introduced as a promising approach to enhance the efficiency and the stability of CQDs solar cells. Very recently, Loi's group introduced s‐SWCNTs as a single thin layer sandwiched between PbS CQD active layer and the Au top anode ( Figure a) . Here, the upper part of the active layer was treated with tetrabutylammonium iodide (TBAI), while the bottom part was treated with ethanedithiol (EDT) to induce n‐ and p‐type characteristics, respectively.…”

“…b) EQE spectra and c) PCEs of the devices with (black curves) and without (red curves) s‐SWCNT thin layer. Reproduced with permission . Copyright 2018, Wiley‐VCH.…”