| 1. |
- Aitola, Kerttu, et al.
(författare)
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Carbon nanotube-based hybrid hole-transporting material and selective contact for high efficiency perovskite solar cells
- 2016
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 9:2, s. 461-466
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a high efficiency perovskite solar cell with a hybrid hole-transporting material-counter electrode based on a thin single-walled carbon nanotube (SWCNT) film and a drop-cast 2,2,7,-7-tetrakis(N, N-di-p-methoxyphenylamine)-9,90-spirobifluorene (Spiro-OMeTAD) hole-transporting material (HTM). The average efficiency of the solar cells was 13.6%, with the record cell yielding 15.5% efficiency. The efficiency of the reference solar cells with spin-coated Spiro-OMeTAD hole-transportingmaterials (HTMs) and an evaporated gold counter electrode was 17.7% (record 18.8%), that of the cells with only a SWCNT counter electrode (CE) without additional HTM was 9.1% (record 11%) and that of the cells with gold deposited directly on the perovskite layer was 5% (record 6.3%). Our results show that it is possible to manufacture high efficiency perovskite solar cells with thin film (thickness less than 1 mu m) completely carbon-based HTMCEs using industrially upscalable manufacturing methods, such as press-transferred CEs and drop-cast HTMs.
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| 2. |
- Cheng, Ming, et al.
(författare)
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Acceptor Donor Acceptor type ionic molecule materials for efficient perovskite solar cells and organic solar cells
- 2016
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Ingår i: Nano Energy. - : Elsevier BV. - 2211-2855. ; 30, s. 387-397
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite solar cells (PSCs) have attracted significant interest and hole transporting materials (HTMs) play important roles in achieving high efficiency. Here, we report additive free ionic type HTMs that are based on 2-ethylhexyloxy substituted benzodithiophene (BDT) core unit. With the ionization of end-capping pyridine units, the hole mobility and conductivity of molecular materials are greatly improved. Applied in PSCs, ionic molecular material M7-TFSI exhibits the highest efficiency of 17.4% in the absence of additives [lithium bis(trifluor-omethanesulfonyl)imide and 4-tert-butylpyridine]. The high efficiency is attributed to a deep highest occupied molecular orbital (HOMO) energy level, high hole mobility and high conductivity of M7-TFSI. Moreover, due to the higher hydrophobicity of M7-TFSI, the corresponding PSCs showed better stability than that of Spiro-OMeTAD based ones. In addition, the strong absorption and suitable energy levels of materials (M6, M7-13r and M7-TFSI) also qualify them as donor materials in organic solar cells (OSCs) and the devices containing M7-TFSI as donor material displayed an efficiency of 6.9%.
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| 3. |
- Hua, Yong, et al.
(författare)
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Facile synthesis of fluorene-based hole transport materials for highly efficient perovskite solar cells and solid-state dye-sensitized solar cells
- 2016
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Ingår i: Nano Energy. - : Elsevier. - 2211-2855 .- 2211-3282. ; 26, s. 108-113
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Tidskriftsartikel (refereegranskat)abstract
- Two novel low-cost fluorene-based hole transport materials (HTMs) HT1 and HT2 as alternatives to the expensive HTM Spiro-OMeTAD have been designed and synthesized for the application in perovskite solar cells (PSCs) and solid-state dye-sensitized solar cell (ssDSCs). The two HTMs were prepared through a facile two-step reaction from cheap starting material and with a total yield higher than 90%. These HTMs exhibit good solubility and charge-transport ability. PSCs based on HT2 achieved power conversion efficiency (PCE) of 18.04% under air conditions, which is comparable to that of the cell employing the commonly used Spiro-OMeTAD (18.27%), while HT1-based cell showed a slightly worse performance with a PCE of 17.18%. For ssDSCs, the HT2-based device yielded a PCE of 6.35%, which is also comparable to that of a cell fabricated based on Spiro-OMeTAD (6.36%). We found that the larger dimensional structure and molecular weight of HT2 enable better photovoltaic performance than that of the smaller one HT1. These results show that easily synthesized fluorene-based HTMs have great potential to replace the expensive Spiro-OMeTAD for both PSCs and ssDSCs.
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| 4. |
- Sveinbjörnsson, Kári, et al.
(författare)
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Ambient air-processed mixed-ion perovskites for high-efficiency solar cells
- 2016
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 4:42, s. 16536-16545
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Tidskriftsartikel (refereegranskat)abstract
- Mixed-ion (FAPbI(3))(1-x)(MAPbBr(3))(x) perovskite solar cells have achieved power conversion efficiencies surpassing 20%. However, in order to obtain these high efficiencies the preparation is performed in a controlled inert atmosphere. Here, we report a procedure for manufacturing highly efficient solar cells with a mixed-ion perovskite in ambient atmosphere. By including a heating step at moderate temperatures of the mesoporous titanium dioxide substrates, and spin-coating the perovskite solution on the warm substrates in ambient air, a red intermediate phase is obtained. Annealing the red phase at 100 degrees C results in a uniform and crystalline perovskite film, whose thickness is dependent on the substrate temperature prior to spin-coating. The temperature was optimized between 20 and 100 degrees C and it was observed that 50 degrees C substrate temperature yielded the best solar cell performances. The average efficiency of the best device was 17.6%, accounting for current-voltage (I-V) measurement hysteresis, with 18.8% performance in the backward scan direction and 16.4% in the forward scan direction. Our results show that it is possible to manufacture high-efficiency mixed-ion perovskite solar cells under ambient conditions, which is relevant for large-scale and low-cost device manufacturing processing.
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| 5. |
- Zhang, Xiaoliang, et al.
(författare)
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Fine Tuned Nanolayered Metal/Metal Oxide Electrode for Semitransparent Colloidal Quantum Dot Solar Cells
- 2016
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 26:12, s. 1921-1929
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Tidskriftsartikel (refereegranskat)abstract
- Semitransparent photovoltaics have great potential, for example, in buildingintegrationor in portable electronics. However, the front and back contactelectrodes signifi cantly affect the light transmission and photovoltaic performanceof the complete device. Herein, the use of a semitransparentnanolayered metal/metal oxide electrode for a semitransparent PbS colloidalquantum dot solar cell to increase the light transmission and power conversioneffi ciency is reported. The effect of the nanolayered electrode on theoptical properties within the solar cells is studied and compared to a theoreticallymodel to identify the origin of optical losses that lower the devicetransmission. The results show that the light transmission in the visibleregion and the photovoltaic performance are signifi cantly enhanced with thenanolayered electrode. The solar cell shows an effi ciency of 5.4% and averagevisible transmittance of 24.1%, which is an increase by 28.6% and 59.6%,respectively, compared to the device with a standard Au fi lm as the electrode.These results demonstrate that the optical and electrical modifi cation oftransparent electrode is possible and essential for reducing the light refl ectionand absorption of the electrode in semitransparent photovoltaics, and,meanwhile the demonstrated nanolayered materials may provide an avenuefor enhancing the device transparency and efficiency.
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