| 1. |
- Xiong, Shaobing, et al.
(författare)
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Defect-Passivation Using Organic Dyes for Enhanced Efficiency and Stability of Perovskite Solar Cells
- 2020
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Ingår i: Solar RRL. - : WILEY-V C H VERLAG GMBH. - 2367-198X. ; 4:5
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite solar cells are a highly competitive candidate for next-generation photovoltaic technology. Defects in the perovskite grain boundaries and on the film surfaces however have significant impacts on both the device efficiency and environmental stability. Herein, a strategy using organic dyes as additives to passivate the defect states and produce more n-type perovskite films, thereby improving charge transport and decreasing charge recombination, is reported. Based on this strategy, the power conversion efficiency of the perovskite solar cell is significantly increased from 18.13% to 20.18% with a negligible hysteresis. Furthermore, the rich hydrogen bonds and carbonyl structures in the organic dye can significantly enhance device stability both in terms of humidity and thermal stress. The results present a promising pathway using abundant and colorful organic dyes as additives to achieve high-performance perovskite solar cells.
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| 2. |
- Xiong, Shaobing, et al.
(författare)
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Engineering of the Back Contact between PCBM and Metal Electrode for Planar Perovskite Solar Cells with Enhanced Efficiency and Stability
- 2019
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Ingår i: Advanced Optical Materials. - : WILEY-V C H VERLAG GMBH. - 2162-7568 .- 2195-1071. ; 7:19
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Tidskriftsartikel (refereegranskat)abstract
- The cathode interface plays a critical role in achieving high-performance fullerene/perovskite planar solar cells. Herein, the simple molecule Isatin and its derivatives are introduced at the back contact [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/Al as a cathode modification interlayer. It is revealed that the Isatin interlayers facilitate electron transport/extraction and suppress electron recombination, attributed to the formation of negative dipole potential steps and the passivation of the interfacial trap density. The average power conversion efficiencies of the resulting devices are significantly improved by 11% from 17.68% to 19.74%, with an enhancement in all device parameters including short-circuit current, open-circuit voltage, and fill factor. The hysteresis index is found to disappear. In addition, such interlayer enhances device stability under ambient conditions compared to the control devices due to suppression of moisture-induced degradation of the perovskite films. These findings provide a comprehensive understanding of the engineering of the back contact between PCBM and the metal electrode to improve efficiency and stability of perovskite solar cells.
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| 3. |
- Yang, Jianming, et al.
(författare)
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Energetics and Energy Loss in 2D Ruddlesden-Popper Perovskite Solar Cells
- 2020
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Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 10:23
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Tidskriftsartikel (refereegranskat)abstract
- 2D Ruddlesden-Popper perovskites (RPPs) are emerging as potential challengers to their 3D counterpart due to superior stability and competitive efficiency. However, the fundamental questions on energetics of the 2D RPPs are not well understood. Here, the energetics at (PEA)(2)(MA)(n)-1PbnI3n+1/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) interfaces with varying n values of 1, 3, 5, 40, and infinity are systematically investigated. It is found that n-n junctions form at the 2D RPP interfaces (n = 3, 5, and 40), instead of p-n junctions in the pure 2D and 3D scenarios (n = 1 and infinity). The potential gradient across phenethylammonium iodide ligands that significantly decreases surface work function, promotes separation of the photogenerated charge carriers with electron transferring from perovskite crystal to ligand at the interface, reducing charge recombination, which contributes to the smallest energy loss and the highest open-circuit voltage (V-oc) in the perovskite solar cells (PSCs) based on the 2D RPP (n = 5)/PCBM. The mechanism is further verified by inserting a thin 2D RPP capping layer between pure 3D perovskite and PCBM in PSCs, causing the V-oc to evidently increase by 94 mV. Capacitance-voltage measurements with Mott-Schottky analysis demonstrate that such V-oc improvement is attributed to the enhanced potential at the interface.
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| 4. |
- Zhou, Zichun, et al.
(författare)
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High-efficiency small-molecule ternary solar cells with a hierarchical morphology enabled by synergizing fullerene and non-fullerene acceptors
- 2018
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Ingår i: NATURE ENERGY. - : NATURE PUBLISHING GROUP. - 2058-7546. ; 3:11, s. 952-959
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Tidskriftsartikel (refereegranskat)abstract
- Using combinatory photoactive blends is a promising approach to achieve high power conversion efficiency in ternary organic photovoltaics. However, the fundamental challenge of how to manipulate the morphology of multiple components and correlate structure details via device performance has not been well addressed. Achieving an ideal morphology that simultaneously enhances charge generation and transport and reduces voltage loss is an imperative avenue to improve device efficiency. Here, we achieve a high power conversion efficiency of 13.20 +/- 0.25% for ternary solar cells by using a combination of small molecules with both fullerene and non-fullerene acceptors, which form a hierarchical morphology consisting of a PCBM transporting highway and an intricate non-fullerene phase-separated pathway network. Carrier generation and transport find an optimized balance, and voltage loss is simultaneously reduced. Such a morphology fully utilizes the individual advantages of both fullerene and non-fullerene acceptors, demonstrating their indispensability in organic photovoltaics.
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