| 1. |
- Zhang, Xiaoliang, et al.
(författare)
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Inorganic CsPbI3 Perovskite Coating on PbS Quantum Dot for Highly Efficient and Stable Infrared Light Converting Solar Cells
- 2018
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Ingår i: Advanced Energy Materials. - : Wiley-VCH Verlagsgesellschaft. - 1614-6832 .- 1614-6840. ; 8:6
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Tidskriftsartikel (refereegranskat)abstract
- Solution-processed colloidal quantum dot (CQD) solar cells harvesting the infrared part of the solar spectrum are especially interesting for future use in semitransparent windows or multilayer solar cells. To improve the device power conversion efficiency (PCE) and stability of the solar cells, surface passivation of the quantum dots is vital in the research of CQD solar cells. Herein, inorganic CsPbI3 perovskite (CsPbI3-P) coating on PbS CQDs with a low-temperature, solution-processed approach is reported. The PbS CQD solar cell with CsPbI3-P coating gives a high PCE of 10.5% and exhibits remarkable stability both under long-term constant illumination and storage under ambient conditions. Detailed characterization and analysis reveal improved passivation of the PbS CQDs with the CsPbI3-P coating, and the results suggest that the lattice coherence between CsPbI3-P and PbS results in epitaxial induced growth of the CsPbI3-P coating. The improved passivation significantly diminishes the sub-bandgap trap-state assisted recombination, leading to improved charge collection and therefore higher photovoltaic performance. This work therefore provides important insight to improve the CQD passivation by coating with an inorganic perovskite ligand for photovoltaics or other optoelectronic applications.
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| 2. |
- Yuan, Lin, et al.
(författare)
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Four-Terminal Tandem Solar Cell with Dye-Sensitized and PbS Colloidal Quantum-Dot-Based Subcells
- 2020
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Ingår i: ACS Applied Energy Materials. - : AMER CHEMICAL SOC. - 2574-0962. ; 3:4, s. 3157-3161
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Tidskriftsartikel (refereegranskat)abstract
- In this work, high-performance four-terminal solution-processed tandem solar cells were fabricated by using dye-sensitized solar cells (DSSCs) as top-cells and lead sulfide (PbS) colloidal quantum dot solar cells (CQDSCs) as bottom-cells. For dye-sensitized top-cells, three different dye combinations were used while the titanium dioxide (TiO2) scattering layer was removed to maximize the transmission. For the PbS bottom-cells, quantum dots with different sizes were compared. Over 12% power conversion efficiency has been achieved by using the XL dye mixture and 890 nm PbS QDs, which shows a significant efficiency enhancement when compared to single DSSC or CQDSC subcells.
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| 3. |
- Öberg, Viktor A., et al.
(författare)
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Cubic AgBiS2 Colloidal Nanocrystals for Solar Cells
- 2020
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Ingår i: ACS APPLIED NANO MATERIALS. - : American Chemical Society (ACS). - 2574-0970. ; 3:5, s. 4014-4024
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Tidskriftsartikel (refereegranskat)abstract
- Recent progress in colloidal quantum dot (CQD)-based solar cells indicates that low-toxicity materials such as AgBiS2 nanocrystals (NCs) show potential in replacing toxic PbS and CdS CQDs in solar cell applications. In this study, an investigation on the importance of the composition and sensitivity toward synthesis conditions was performed by adjusting concentrations and ratios of Ag and Bi precursors-first, by varying the ratio of Ag toward Bi precursors and, second, by varying the concentration of Ag with a constant ratio toward Bi precursors in the solution. Furthermore, elemental XPS studies and TEM imaging together with solar cell analysis indicated a strong correlation between the concentration of Ag precursor and the NC properties and, moreover, the solar cell properties based on these NCs. In short, a large amount of Ag precursor resulted in smaller Ag-rich NCs, which resulted in solar cells with high photovoltage but low photocurrent density, while a lower amount of Ag precursor resulted in larger NCs and solar cells with a lower photovoltage. The Ag:Bi:S ratio of 0.72:0.9:1 resulted in almost stoichiometric NCs but with a slight excess of Ag, which in turn resulted in solar cells with the highest performance. This work therefore gives insight into how the elemental composition and size of the NCs can be tuned by the precursor ratios and how this, in turn, affects the performance of the solar cell devices.
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| 4. |
- Öberg, Viktor A., et al.
(författare)
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Hot-Injection Synthesized Ag2S Quantum Dots with Broad Light Absorption and High Stability for Solar Cell Applications
- 2018
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Ingår i: ChemNanoMat. - : Wiley. - 2199-692X. ; 4:12, s. 1223-1230
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Tidskriftsartikel (refereegranskat)abstract
- A hot-injection synthesis method was used to synthesize low-toxicity Ag2S colloidal quantum dots (CQDs) with strong and broad light absorption as an ultra-thin photo-absorber in CQD heterojunction solar cells. By using iodide and sulfur linkers it was possible to accomplish efficient charge carrier extraction, resulting in a high photocurrent due to the broad absorption spectrum. Transient photovoltage decay measurements were used to obtain information about trap states in the CQDs and the effect on the lifetime of the photoinduced carriers. The devices show very promising stability under constant long-term illumination and they are stable under ambient storage conditions with low losses to the performance over a period of over two months. These results show that Ag2S CQDs have high potential within solar cell applications, and point the direction for further improvements.
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| 5. |
- Öberg, Viktor A., et al.
(författare)
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Solution-Processed Environmentally Friendly Ag2S Colloidal Quantum Dot Solar Cells with Broad Spectral Absorption
- 2017
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Ingår i: Applied Sciences. - : MDPI AG. - 2076-3417. ; 7:10
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Tidskriftsartikel (refereegranskat)abstract
- A facile heat-up synthesis route is used to synthesize environmentally friendly Ag2S colloidal quantum dots (CQDs) that are applied as light absorbing material in solid state p-i-n junction solar cell devices. The as-synthesized Ag2S CQDs have an average size of around 3.5 nm and exhibit broad light absorption covering ultraviolet, visible, and near infrared wavelength regions. The solar cell devices are constructed with a device architecture of FTO/TiO2/Ag2S CQDs/hole transport material (HTM) /Au using a solution-processed approach. Different HTMs, N2,N2,N2′,N2′,N7,N7,N7′,N7′-octakis(4-methoxyphenyl)-9,9′-spirobi(9H-fluorene)-2,2′,7,7′ tetramine (spiro-OMeTAD), poly(3-hexylthiophene-2,5-diyl) (P3HT), and poly((2,3-bis(3-octyloxyphenyl)-5,8-quinoxalinediyl)-2,5-thiophenediyl) TQ1 are studied for maximizing the device photovoltaic performance. The solar cell device with P3HT as a hole transport material gives the highest performance and the solar cell exhibit broad spectral absorption. These results indicate that Ag2S CQD have high potential for utilization as environmentally friendly light absorbing materials for solar cell application and that the hole transport material is critical to maximize the solar cell photovoltaic performance.
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| 6. |
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