Scalable PbS Quantum Dot Solar Cell Production by Blade Coating from Stable Inks

Abstract

The recent development of phase transfer ligand exchange methods for PbS quantum dots (QD) has enhanced the performance of quantum dots solar cells and greatly simplified the complexity of film deposition. However, the dispersions of PbS QDs (inks) used for film fabrication often suffer from colloidal instability, which hinders large-scale solar cell production. In addition, the wasteful spin-coating method is still the main technique for the deposition of QD layer in solar cells. Here, we report a strategy for scalable solar cell fabrication from highly stable PbS QD inks. By dispersing PbS QDs capped with CH3NH3PbI3 in 2,6-difluoropyridine (DFP), we obtained inks that are colloidally stable for more than 3 months. Furthermore, we demonstrated that DFP yields stable dispersions even of large diameter PbS QDs, which are of great practical relevance owing to the extended coverage of the near-infrared region. The optimization of blade-coating deposition of DFP-based inks enabled the fabrication of PbS QD solar cells with power conversion efficiencies of up to 8.7%. It is important to underline that this performance is commensurate with the devices made by spin coating of inks with the same ligands. A good shelf life-time of these inks manifests itself in the comparatively high photovoltaic efficiency of 5.8% obtained with inks stored for more than 120 days.

Matching Charge Extraction Contact for Infrared PbS Colloidal Quantum Dot Solar Cells

“…[16] This method mainly consists of two steps, the first step is the synthesis of ZnS QDs (Figure S1, Supporting Information), and the other step is the exchange of zinc cations with Pb ions in the PbCl 2 precursor solution. Unlike the traditional hot injection method, [17] the nucleus and size growth of present synthesis are independently controlled in order to improve the QD quality. Figure 2a shows the absorption and PL spectra of as-synthesized PbS QDs solution.…”

Suppressing the Dark Current in Quantum Dot Infrared Photodetectors by Controlling Carrier Statistics

“…Exten sive studies have been conducted to improve light absorbance by utilizing the microcavity effect of oxide/metal/oxide multi layers, [23] plasmonic effect of metal nanostructures, [24,25] and blade coating which increases the active layer thickness. [26,27] Energy band engineering and doping strategies have also been developed between the n + n and the n-p junction to effectively dissociate the generated exciton by doping ZnO with K or Cs [28,29] and PbS with halide. [30] Postchemical treatment, [15,31] or surface passivation methods, [13,18] have been investigated to improve the carrier mobility and lifetime for efficient charge transport.…”

Performance Enhancement of Polycrystalline Silicon Solar Cell through Sputter Coated Molybdenum Disulphide Surface Films

“…The energy band gap of MoS2 is found to be 1.8 eV [10]. Thin film ARC can be deposited over solar cell surface through various techniques such asslot-die coating [11], blade coating [12], spin coating [13], sputter coating [4], electrospinning [14,15], spray pyrolysis [16] etc.…”