Enhancing Electron and Hole Extractions for Efficient PbS Quantum Dot Solar Cells

Abstract

Exploring ways capable of enhancing photocarrier extraction is crucial in further developing the current PbS quantum dots (QDs) solar cells with a standard architecture of ITO/ZnO/PbS‐TBAI/PbS‐EDT/Au, which are drawing enormous attention due to their high air stabilities and already achieved high power conversion efficiencies. Here, a thin layer of carbon QDs (CQDs) is employed to modify the ZnO film surface to improve photoelectron extraction, and a thin film of PbS QDs treated by a mixed ligand solution of EDT:CuI (PbS‐EDT:CuI) is used to replace the PbS‐EDT film to improve photohole extraction. This designed device (ITO/ZnO/CQDs/PbS‐TBAI/PbS‐EDT:CuI/Au) presents significantly improved PCE of 9.95% compared to 8.60% of the reference device (ITO/ZnO/PbS‐TBAI/PbS‐EDT/Au). In addition, the designed device shows very high air stability.

Studies of Graphdiyne‐ZnO Nanocomposite Material and Application in Polymer Solar Cells

“…The GDZO solution (12 mg mL −1 in trifluoroethanol) was spin‐coated on ITO at 2000 rpm 60 s. After thermal annealing at 100 °C for 15 min in air, GDZO film is formed. To investigate the morphology and surface wettability of GDZO, SEM, and contact angle of water measurements were performed, as shown in Figure (b–g) . Through the comparison of Figure (b) (ZnO film) and (e) (GDZO film), we can observe that GDZO film is more dense and smooth.…”

Quantum Dot Solar Cells: Small Beginnings Have Large Impacts

“…Analogously, increased p-type doping of the HTL via molecular doping [18] and sodium hydrosulphide (NaHS) treatment [209] has also shown to increase the depletion width in the absorber layer in addition to improving band bending at the interface during the maximum power point condition leading to high fill factors (FF) and high PCE solar cells. Introducing extra electron transport layers (ETLs) and HTLs [196,[210][211][212][213] at these interfaces have also been reported to improve device performance. ETLs are chosen such that they passivate the surface defects present in the metal oxide layer and also promote favorable band bending at the interface between the metal oxide layer and the n type QD films that improves the built-in and open circuit voltage.…”

“…ETLs are chosen such that they passivate the surface defects present in the metal oxide layer and also promote favorable band bending at the interface between the metal oxide layer and the n type QD films that improves the built-in and open circuit voltage. These ETLs can be self-assembled monolayers (SAMs) formed by treating the metal oxide layer with organic solutions like tetrahydrofuran [184] and aminobenzoic acid [197] or other intermediate buffer layers made of materials like carbon QDs [212], CdSe QDs [214], mixed nanocrystals [188], magnesium-doped ZnO [215] or other organic buffers [216] that have given rise to devices with PCEs >9%. While all these ETLs are used in conjunction with a metal oxide layer, recently, CdS has also been successfully used as an n-type electrode instead of a metal oxide to make a heterojunction QDSC with a PCE of 8% [217].…”

Ligand dependent oxidation dictates the performance evolution of high efficiency PbS quantum dot solar cells

“…Consequently, it has become routine in literature to perform preconditioning procedures, such as exposure to air prior to photovoltaic characterization. 8,15,[20][21][22][23] However, these procedures are not standardized and a clear understanding of the evolution of the photovoltaic performance upon exposure to environmental factors has not emerged.…”