Strong Coupling of Colloidal Quantum Dots via Self‐Assemble Passivation for Efficient Infrared Solar Cells

Zheng, Siyu; Wang, Yunfei; Jia, Donglin; Tian, Lei; Chen, Jingxuan; Shan, Lianwei; Dong, Limin; Zhang, Xiaoliang

doi:10.1002/admi.202100489

Cited by 12 publications

(12 citation statements)

References 53 publications

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“…26 Recent work has shown that the binding energy of the core level Pb 4f spectrum will shift to a higher energy in the presence of PbI 2 on the PbS QD surface. 38 We also found that the binding energy of the Pb 4f core level peak in the PbAc-MAAc film shifts to a higher energy toward the reference PbI 2 peak position, consistent with the interpretation that MAPbI 3−x Ac x decomposes upon heating, leaving behind PbI 2 in the QD film (see Figure S6). SWIR Photodiode Performances.…”

Section: ■ Results and Discussionsupporting

confidence: 86%

“…As shown in Figure a, the absence of the nitrogen peaks in the XPS spectra confirms the thermal decomposition of MAPbI 3– x Ac x as the presence of MA cations should be associated with the nitrogen peaks in the XPS spectra . Recent work has shown that the binding energy of the core level Pb 4f spectrum will shift to a higher energy in the presence of PbI 2 on the PbS QD surface . We also found that the binding energy of the Pb 4f core level peak in the PbAc-MAAc film shifts to a higher energy toward the reference PbI 2 peak position, consistent with the interpretation that MAPbI 3– x Ac x decomposes upon heating, leaving behind PbI 2 in the QD film (see Figure S6).…”

Section: Resultssupporting

confidence: 75%

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Enhanced Surface Passivation of Lead Sulfide Quantum Dots for Short-Wavelength Photodetectors

Yin

Ding

et al. 2022

Chem. Mater.

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Lead sulfide (PbS) quantum dots are promising solution-processed materials for short-wave infrared (SWIR) photodetectors due to their tunable band gap and solution processability. Phase-transfer ligand exchange is a common method to prepare quantum dot (QD) inks used in device fabrication. For large-sized PbS QDs used for SWIR detection, the conventional phase-transfer ligand exchange has been problematic due to the densely packed organic ligands and charge-neutral (100) facets.Here, we report a new strategy to carry out the efficient phasetransfer ligand exchange in large-sized QDs. Specifically, using lead acetate trihydrate (PbAc 2 •3H 2 O) as a precursor and methylammonium acetate (MAAc) as an additive in the ligand solution, we can facilitate the efficient phase-transfer ligand exchange and epitaxial growth of perovskite intermediate (MAPbI 3−x Ac x ) on the (100) facets, resulting in a significant improvement in film quality suitable for device fabrication. The resulting photodiodes show a 2.5× enhancement in external quantum efficiency (EQE) compared to devices using QD inks obtained using the conventional method. Considering the low transmittance of the ITO electrode in the SWIR regime, our devices exhibit an internal quantum efficiency of over 90%.

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Section: ■ Results and Discussionsupporting

confidence: 86%

Section: Resultssupporting

confidence: 75%

Enhanced Surface Passivation of Lead Sulfide Quantum Dots for Short-Wavelength Photodetectors

Yin

Ding

et al. 2022

Chem. Mater.

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“…Due to the combined advantages of perovskites and quantum dots (QDs), such as low cost, solution processability, tunable bandgap energy (E g ) and high stability [1][2][3][4][5][6][7][8][9], perovskite QDs (PQDs) have received increasing attention for application in light-emitting diodes [10,11], photodetector [12][13][14], and solar cells [15,16]. Since the first PQD solar cells (PQDSCs) were successfully fabricated by Swarnkar et al in 2016 [17], with the material synthesis improvement [18][19][20], post-treatment of PQDs [21][22][23][24][25], and tuning device structure of solar cells [26][27][28][29], the performance of inorganic CsPbI 3 PQDSCs has considerably improved.…”

Section: Introductionmentioning

confidence: 99%

Ligand exchange engineering of FAPbI3 perovskite quantum dots for solar cells

Fan

Gao

Mei

et al. 2022

Front. Optoelectron.

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Formamidinium lead triiodide (FAPbI3) perovskite quantum dots (PQDs) show great advantages in photovoltaic applications due to their ideal bandgap energy, high stability and solution processability. The anti-solvent used for the post-treatment of FAPbI3 PQD solid films significantly affects the surface chemistry of the PQDs, and thus the vacancies caused by surface ligand removal inhibit the optoelectronic properties and stability of PQDs. Here, we study the effects of different anti-solvents with different polarities on FAPbI3 PQDs and select a series of organic molecules for surface passivation of PQDs. The results show that methyl acetate could effectively remove surface ligands from the PQD surface without destroying its crystal structure during the post-treatment. The benzamidine hydrochloride (PhFACl) applied as short ligands of PQDs during the post-treatment could fill the A-site and X-site vacancies of PQDs and thus improve the electronic coupling of PQDs. Finally, the PhFACl-based PQD solar cell (PQDSC) achieves a power conversion efficiency of 6.4%, compared to that of 4.63% for the conventional PQDSC. This work provides a reference for insights into the surface passivation of PQDs and the improvement in device performance of PQDSCs. Graphical abstract

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“…CQDs were synthesized using a modified Schlenk line process in a nitrogen atmosphere 16 . Pb(AC)2 (1.55 g), OA (3 mL), and ODE (20 mL) were added to a flask (250 mL).…”

Section: Ligand Exchange Of Pbs Cqdsmentioning

confidence: 99%

“…Colloidal quantum dot (CQD) is one of the most competitive infrared optoelectronic materials for emerging infrared applications [1][2][3] , such as photodetectors [4][5][6][7] , light-emitting devices (LEDs) [8][9][10] , and solar cells [11][12][13][14][15][16] , due to its strong infrared absorption, high stability, solution processibility and sizedependent bandgap energy [17][18][19][20][21] . In particular, for photovoltaic applications, the multi-exciton generation (MEG) of the CQD makes it possible to break through the Shockley-Queisser efficient limitation of single-junction solar cells that more than one electron-hole pair could be produced after absorption of one high energy photon 22,23 .…”

mentioning

confidence: 99%

Colloidal Quantum Dot Solids with a Diminished Epitaxial PbI<sub>2</sub> Matrix for Efficient Infrared Solar Cells

Zhang¹,

Zhou²,

Mei³

et al. 2022

Acta Physico Chimica Sinica

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Colloidal quantum dots (CQDs) are extremely promising infrared optoelectronic materials for efficient solar cells owing to their strong infrared absorption with tunable spectra. However, the liquid-state ligand exchange of CQDs using ammonium acetate (AA) as an additive generally resulted in intensive charge-transport barriers within the CQD solids. This is induced by the highbandgap PbI2 matrix, which considerably affects the charge-carrier extraction of CQD solar cells (CQDSCs), and thus their photovoltaic performance. Herein, dimethylammonium iodide (DMAI) was used as an additive instead for the liquidstate ligand exchange, substantially eliminating the PbI2 matrix capping the CQDs and simultaneously restraining CQD fusion during the ligand exchange, thereby reducing the barriers for the charge-carrier transport within the CQD solids. Extensive experimental studies and theoretical calculations were performed to link the surface chemistry of the CQDs with the charge-carrier dynamics within the CQD solids and full solar cell devices. The theoretical calculation results reveal that DMAI which possess small dissociation energy could finely regulate the ligand exchange of CQDs, resulting in the suppressed energetic disorder and diminished charge-transport barriers in the CQD solids compared to those of the CQD solids prepared using AA. The DMAI-treated quantum dots were characterized and analyzed by transmission electron microscopy, X-ray photoelectron spectroscopy, and 2D grazing-incidence wide-and small-angle X-ray scattering spectrometry. The results show PbI2-related Bragg peaks in the AA-treated CQD solid films, indicating a thick layer of PbI2 crystal matrix being formed in the CQD solids, whereas there was no obvious PbI2 signal observed in DMAI-treated CQD solids. These results also demonstrate that DMAI provides additional I − , improving the surface passivation of the CQDs and reducing trap-assisted recombination. For the infrared photovoltaic applications, the CQDSC devices were fabricated, which shows that the photovoltaic performance of CQDSCs was significantly improved. The power conversion efficiency of DMAI-based CQDSCs was improved by 17.8% compared with that of the AA-based CQDSC. The charge-carrier dynamics in both CQD solids and full solar cell devices were analyzed in detail, revealing that the improved photovoltaic performance in DMAI-based CQDSCs was attributed to the facilitated charge-carrier transport within the CQD solids and suppressed trap-assisted recombination, resulting from eliminated charge-transport barriers and improved surface passivation of CQDs, respectively. This work provides a new avenue to controlling the surface chemistry of infrared CQDs and a feasible approach to substantially diminishing the charge transfer barriers of CQD solids for infrared solar cells.

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Strong Coupling of Colloidal Quantum Dots via Self‐Assemble Passivation for Efficient Infrared Solar Cells

Cited by 12 publications

References 53 publications

Enhanced Surface Passivation of Lead Sulfide Quantum Dots for Short-Wavelength Photodetectors

Enhanced Surface Passivation of Lead Sulfide Quantum Dots for Short-Wavelength Photodetectors

Ligand exchange engineering of FAPbI3 perovskite quantum dots for solar cells

Colloidal Quantum Dot Solids with a Diminished Epitaxial PbI<sub>2</sub> Matrix for Efficient Infrared Solar Cells

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