Precursor Chemistry Enables the Surface Ligand Control of PbS Quantum Dots for Efficient Photovoltaics

The surface ligand environment plays a dominant role in determining the physicochemical, optical, and electronic properties of colloidal quantum dots (CQDs). Specifically, the ligand‐related electronic traps are the main reason for the carrier nonradiative recombination and the energetic losses in colloidal quantum dot solar cells (CQDSCs), which are usually solved with numerous advanced ligand exchange reactions. However, the synthesis process, as the essential initial step to control the surface ligand environment of CQDs, has lagged behind these post‐synthesis ligand exchange reactions. The current PbS CQDs synthesis tactic generally uses lead oxide (PbO) as lead precursor, and thus suffers from the water byproducts issue increasing the surface‐hydroxyl ligands and aggravating trap‐induced recombination in the PbS CQDSCs. Herein, an organic‐Pb precursor, lead (II) acetylacetonate (Pb(acac)2), is used instead of a PbO precursor to avoid the adverse impact of water byproducts. Consequently, the Pb(acac)2 precursor successfully optimizes the surface ligands of PbS CQDs by reducing the hydroxyl ligands and increasing the iodine ligands with trap‐passivation ability. Finally, the Pb(acac)2‐based CQDSCs possess remarkably reduced trap states and suppressed nonradiative recombination, generating a certified record Voc of 0.652 V and a champion power conversion efficiency (PCE) of 11.48% with long‐term stability in planar heterojunction‐structure CQDSCs.

[1]  T. Sagawa,et al.  The effect of water on colloidal quantum dot solar cells , 2021, Nature Communications.

[2]  Xiaoliang Zhang,et al.  Regulating Thiol Ligands of p-Type Colloidal Quantum Dots for Efficient Infrared Solar Cells , 2021 .

[3]  X. Zu,et al.  Defects, photophysics and passivation in Pb-based colloidal quantum dot photovoltaics , 2021 .

[4]  Shujuan Huang,et al.  Optimizing Surface Chemistry of PbS Colloidal Quantum Dot for Highly Efficient and Stable Solar Cells via Chemical Binding , 2020, Advanced science.

[5]  Joonhyuck Park,et al.  Controllable modulation of precursor reactivity using chemical additives for systematic synthesis of high-quality quantum dots , 2020, Nature Communications.

[6]  Yun‐Hi Kim,et al.  A Tuned Alternating D–A Copolymer Hole‐Transport Layer Enables Colloidal Quantum Dot Solar Cells with Superior Fill Factor and Efficiency , 2020, Advanced materials.

[7]  F. Liu,et al.  Passivation Strategy of Reducing Both Electron and Hole Trap States for Achieving High-Efficiency PbS Quantum-Dot Solar Cells with Power Conversion Efficiency over 12% , 2020 .

[8]  T. Peng,et al.  Fabrication of PbS nanocrystal-sensitized ultrafine TiO2 nanotubes for efficient and unusual broadband-light-driven hydrogen production , 2020 .

[9]  F. Pelayo García de Arquer,et al.  Monolayer Perovskite Bridges Enable Strong Quantum Dot Coupling for Efficient Solar Cells , 2020 .

[10]  Liang Gao,et al.  Facet Control for Trap‐State Suppression in Colloidal Quantum Dot Solids , 2020, Advanced Functional Materials.

[11]  Andrew H. Proppe,et al.  Ligand-Assisted Reconstruction of Colloidal Quantum Dots Decreases Trap State Density. , 2020, Nano letters.

[12]  Fan Yang,et al.  Room-temperature direct synthesis of semi-conductive PbS nanocrystal inks for optoelectronic applications , 2019, Nature Communications.

[13]  Jiang Tang,et al.  Cation‐Exchange Synthesis of Highly Monodisperse PbS Quantum Dots from ZnS Nanorods for Efficient Infrared Solar Cells , 2019, Advanced Functional Materials.

[14]  Haihui Wang,et al.  Self-Crosslinked MXene (Ti3C2Tx) Membranes with Good Anti-Swelling Property for Monovalent Metal Ions Exclusion. , 2019, ACS nano.

[15]  S. Qiao,et al.  Near-Infrared Active Lead Chalcogenide Quantum Dots: Preparation, Post-Synthesis Ligand Exchange, and Applications in Solar Cells. , 2019, Angewandte Chemie.

[16]  Shuchi Gupta,et al.  High-efficiency colloidal quantum dot infrared light-emitting diodes via engineering at the supra-nanocrystalline level , 2018, Nature Nanotechnology.

[17]  Fan Yang,et al.  High‐Efficiency PbS Quantum‐Dot Solar Cells with Greatly Simplified Fabrication Processing via “Solvent‐Curing” , 2018, Advanced materials.

[18]  Aram Amassian,et al.  2D matrix engineering for homogeneous quantum dot coupling in photovoltaic solids , 2018, Nature Nanotechnology.

[19]  M. Loi,et al.  In Situ Passivation for Efficient PbS Quantum Dot Solar Cells by Precursor Engineering , 2018, Advanced materials.

[20]  Oleksandr Voznyy,et al.  Mixed-quantum-dot solar cells , 2017, Nature Communications.

[21]  Jizheng Wang,et al.  Bilayer PbS Quantum Dots for High‐Performance Photodetectors , 2017, Advanced materials.

[22]  Aram Amassian,et al.  Hybrid organic-inorganic inks flatten the energy landscape in colloidal quantum dot solids. , 2017, Nature materials.

[23]  Oleksandr Voznyy,et al.  10.6% Certified Colloidal Quantum Dot Solar Cells via Solvent-Polarity-Engineered Halide Passivation. , 2016, Nano letters.

[24]  G. Gigli,et al.  The Dynamic Organic/Inorganic Interface of Colloidal PbS Quantum Dots. , 2016, Angewandte Chemie.

[25]  Gerasimos Konstantatos,et al.  The role of surface passivation for efficient and photostable PbS quantum dot solar cells , 2016, Nature Energy.

[26]  Illan J. Kramer,et al.  Passivation Using Molecular Halides Increases Quantum Dot Solar Cell Performance , 2016, Advanced materials.

[27]  M. Bawendi,et al.  Identifying and Eliminating Emissive Sub‐bandgap States in Thin Films of PbS Nanocrystals , 2015, Advanced materials.

[28]  Stefan Thiemann,et al.  Light-Emitting Quantum Dot Transistors: Emission at High Charge Carrier Densities , 2015, Nano letters.

[29]  Noah D Bronstein,et al.  Hydroxylation of the surface of PbS nanocrystals passivated with oleic acid , 2014, Science.

[30]  Moungi G. Bawendi,et al.  Improved performance and stability in quantum dot solar cells through band alignment engineering , 2014, Nature materials.

[31]  E. Alarousu,et al.  Real-Time Observation of Ultrafast Intraband Relaxation and Exciton Multiplication in PbS Quantum Dots , 2014 .

[32]  Aram Amassian,et al.  Hybrid passivated colloidal quantum dot solids. , 2012, Nature nanotechnology.

[33]  I. Moreels,et al.  Size-dependent optical properties of colloidal PbS quantum dots. , 2009, ACS nano.

[34]  Gregory D. Scholes,et al.  Colloidal PbS Nanocrystals with Size‐Tunable Near‐Infrared Emission: Observation of Post‐Synthesis Self‐Narrowing of the Particle Size Distribution , 2003 .