Novel post-synthesis purification strategies and the ligand exchange processes in simplifying the fabrication of PbS quantum dot solar cells

Abstract

Quantum dots (QDs) solids with iodide passivation are a key component for most of the well-performing PbS QDs solar cells.

Real-Time X-ray Scattering Discovers Rich Phase Behavior in PbS Nanocrystal Superlattices during In Situ Assembly

“…To observe the effect of the ligand coverage on the self-organized NC superlattice, in this study, we utilize well-purified (4 washing cycles, see the Experimental Section) oleic acid-stabilized 8.2 nm in diameter (with 10% size dispersity) PbS NCs dispersed in heptane as a sample system (Figure c). Such a degree of purification is typically applied to semiconductor nanoparticles for the subsequent utilization in optoelectronic device fabrication. , At this point, it has to be noted that after 4 washing cycles the NCs could be still well suspended in heptane, whereas one more additional precipitation step resulted in ligand-deficient nanoparticles that could not be redispersed homogeneously in the corresponding solvent. The ligand grafting density of PbS NCs after 4 washing cycles was determined using the thermogravimetric analysis to be 2.71 ± 0.27 molecules/nm 2 considering a cuboctahedral shape of the inorganic core (for details see the Supporting Information and Figure S2).…”

Quantum-Size-Effect Tuning Enables Narrowband IR Photodetection with Low Sunlight Interference

“…Tetrabutylammonium iodide (TBAI) passivated CQD have been demonstrated as a large bandgap absorber layer. , We found that this strategy did not translate to small bandgap CQD solids (Figures S3 and S4), but we did assess the potential of TBAI-passivated CQD as photodetector ETLs. TBAI provides n-type doping and increases the electron affinity of the layer, ,, making it potentially suitable for electron extraction. Furthermore, the ligand is exchanged through solid-state methods using ethanol.…”

Nanocrystals as performance-boosting materials for solar cells

“…[121][122][123] Meanwhile, TiO 2 NCs have been widely applied in n-i-p solar cells using chalcogenide NC as light harvesters, such as CdSe, CdS, and PbS. [124][125][126][127][128][129][130] Similarly, ZnO NCs were used as ETL for n-i-p PbS- Review Nanoscale Advances based NC-LHSCs, 30,32,35,39,40,44,45,58,[131][132][133][134][135][136][137][138][139][140][141][142][143][144][145] PSCs, 146 and OSCs. [147][148][149] SnO NCs as ETL for DSSCs, [150][151][152][153][154][155][156] for OSCs, [157][158][159] and for PSCs, 173 NCs have been used as IFL for NC-LHSCs,…”