| 1. |
- Alharbi, Essa A., et al.
(författare)
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Formation of High-Performance Multi-Cation Halide Perovskites Photovoltaics by delta-CsPbI3/delta-RbPbI3 Seed-Assisted Heterogeneous Nucleation
- 2021
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Ingår i: Advanced Energy Materials. - : John Wiley & Sons. - 1614-6832 .- 1614-6840. ; 11:16
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Tidskriftsartikel (refereegranskat)abstract
- The performance of perovskite solar cells is highly dependent on the fabrication method; thus, controlling the growth mechanism of perovskite crystals is a promising way towards increasing their efficiency and stability. Herein, a multi-cation halide composition of perovskite solar cells is engineered via the two-step sequential deposition method. Strikingly, it is found that adding mixtures of 1D polymorphs of orthorhombic delta-RbPbI3 and delta-CsPbI3 to the PbI2 precursor solution induces the formation of porous mesostructured hexagonal films. This porosity greatly facilitates the heterogeneous nucleation and the penetration of FA (formamidinium)/MA (methylammonium) cations within the PbI2 film. Thus, the subsequent conversion of PbI2 into the desired multication cubic alpha-structure by exposing it to a solution of formamidinium methylammonium halides is greatly enhanced. During the conversion step, the delta-CsPbI3 also is fully integrated into the 3D mixed cation perovskite lattice, which exhibits high crystallinity and superior optoelectronic properties. The champion device shows a power conversion efficiency (PCE) over 22%. Furthermore, these devices exhibit enhanced operational stability, with the best device retaining more than 90% of its initial value of PCE under 1 Sun illumination with maximum power point tracking for 400 h.
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| 2. |
- Cappel, Ute B., et al.
(författare)
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A broadly absorbing perylene dye for solid-state dye-sensitized solar cells.
- 2009
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 113:33, s. 14595-14597
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Tidskriftsartikel (refereegranskat)abstract
- We present a new perylene sensitizer, ID 176, for dye-sensitized solar cells (DSCs). The dye has the capability for very high photocurrents due to strong absorption from 400 to over 700 rim. Photocurrents Of LIP to 9 mA cm(-2) were achieved in solid-state DSCs employing the hole conductor 2,2'7,7'-tetrakis-(NN-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-MeOTAD), with a conversion efficiency of 3.2%. In contrast, the sensitizer did not perform well in conjunction with liquid iodide/tri-iodide electrolytes, suggesting a difference in the injection and regeneration mechanisms in these two types of dye-sensitized solar cells.
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| 3. |
- Edvinsson, Tomas, et al.
(författare)
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Intramolecular charge-transfer tuning of perylenes : Spectroscopic features and performance in Dye-sensitized solar cells
- 2007
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 111:42, s. 15137-15140
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Tidskriftsartikel (refereegranskat)abstract
- Five novel perylene molecules with different intramolecular charge-transfer (ICT) characters have been synthesized. The relation between the ICT character for different donating groups and the results for their electro- and photochemical properties as well as their performance in nanostructured dye-sensitized solar cells (nDSC) are reported. With the stronger donors, we obtain a shift of the lowest unoccupied molecular orbital (LUMO) to more negative potential versus normal hydrogen electrode (NHE) as well as an increase the charge separation in the dye upon excitation. Ab initio calculations were used to analyze the effects on orbital energies and electron distribution with the different donors. Incorporating the dyes in nDSCs, we see a drastical improvement in the performance for the more polar dyes. In particular, we find a much improved photovoltage because of higher LUMO levels, allowing conduction band tuning in the TiO2 as well as a contribution from the permanent dipoles in the dyes. The photocurrent improves remarkably with increasing ICT character of the dyes. The external quantum efficiency reached over 70%, and the overall solar-to-electrical energy conversion efficiency was improved to almost 4% for the dye with highest ICT character, which can be compared with devices with the standard N719 dye (Ru(dcbPY)(2)(NCS)(2)) showing 6% under similar conditions. The performance is a significant improvement compared to previous reports for perylenes and lifts the performance from modest to promising. Initial stability tests show that the dye with the highest performance was spectrally stable after more than 2000 h of irradiation in a solar-cell device.
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| 4. |
- Edvinsson, Tomas, et al.
(författare)
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Photoinduced electron transfer from a terrylene dye to TiO2 : Quantification of band edge shift effects
- 2009
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Ingår i: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 357:1-3, s. 124-131
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Tidskriftsartikel (refereegranskat)abstract
- A terrylene chromophore exhibiting a high extinction coefficient has been developed as a sensitizer for photovoltaic applications. The photophysical and photochemical properties of the dye were analyzed both experimentally and theoretically. Terrylene-sensitized nanocrystalline TiO2 solar cells yielded good photocurrents providing more than 60% in external quantum efficiency. The photoinduced electron transfer from the dye to TiO2 was found to be very sensitive to conduction band edge shifts in TiO2 induced, either by changes in the composition of the redox electrolyte or by UV-illumination. This sensitivity was observed in quantum efficiencies for photocurrent generation of terrylene-sensitized solar cells and in photoinduced absorption experiments. The conduction band shifts were quantified using charge extraction methods. The observed sensitivity of the injection efficiency suggests that photoinduced electron transfer occurs from the relaxed excited state, possibly due to poor electronic coupling between TMIMA excited states and TiO2 conduction band states.
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| 5. |
- Jeong, Jaeki, et al.
(författare)
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Pseudo-halide anion engineering for α-FAPbI3 perovskite solar cells
- 2021
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 592:7854, s. 381-385
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Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites of the general formula ABX(3)-where A is a monovalent cation such as caesium, methylammonium or formamidinium; B is divalent lead, tin or germanium; and X is a halide anion-have shown great potential as light harvesters for thin-film photovoltaics(1-5). Among a large number of compositions investigated, the cubic a-phase of formamidinium lead triiodide (FAPbI(3)) hasemerged as the most promising semiconductor for highly efficient and stable perovskite solar cells(6-9), and maximizing the performance of this material in such devices is of vital importance for the perovskite researchcommunity. Here we introduce an anion engineering concept that uses the pseudo-halide anion formate (HCOO-) to suppress anion-vacancy defects that are present at grain boundaries and at the surface of the perovskite films and to augment the crystallinity of the films. Theresulting solar cell devices attain a power conversion efficiency of 25.6 per cent (certified 25.2 per cent), have long-term operational stability (450 hours) and show intense electroluminescence with external quantum efficiencies of more than 10 per cent. Our findings provide a direct route to eliminate the most abundant and deleterious lattice defects present in metal halide perovskites, providing a facile access to solution-processable films with improved optoelectronic performance.
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| 6. |
- Kim, Minjin, et al.
(författare)
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Conformal quantum dot-SnO2 layers as electron transporters for efficient perovskite solar cells
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 375:6578, s. 302-306
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Tidskriftsartikel (refereegranskat)abstract
- Improvements to perovskite solar cells (PSCs) have focused on increasing their power conversion efficiency (PCE) and operational stability and maintaining high performance upon scale-up to module sizes. We report that replacing the commonly used mesoporous-titanium dioxide electron transport layer (ETL) with a thin layer of polyacrylic acid-stabilized tin(IV) oxide quantum dots (paa-QD-SnO2) on the compact-titanium dioxide enhanced light capture and largely suppressed nonradiative recombination at the ETL-perovskite interface. The use of paa-QD-SnO2 as electron-selective contact enabled PSCs (0.08 square centimeters) with a PCE of 25.7% (certified 25.4%) and high operational stability and facilitated the scale-up of the PSCs to larger areas. PCEs of 23.3, 21.7, and 20.6% were achieved for PSCs with active areas of 1, 20, and 64 square centimeters, respectively.
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| 7. |
- Krishna, Anurag, et al.
(författare)
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Mitigating the Heterointerface Driven Instability in Perovskite Photovoltaics
- 2023
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 8:8, s. 3604-3613
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Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites have thepotential to revolutionizethefield of photovoltaics, though limited stability has impeded commercialexploitation. The soft heterointerface between the perovskite andcharge-transporting layer is one of the major bottlenecks that limitsoperational stability. Here, we present rationally designed molecularmodulators that synergistically improve the stability of the & alpha;-FAPbI(3)-based perovskite solar cells while retaining power conversionefficiency (PCE) of 24.0% with a high open-circuit voltage (V (OC)) of & SIM;1.195 V. The interfacially modifiedphotovoltaic cells exhibit high operational stability, whereby thechampion device retains & SIM;88% of initial performance after 2000h of maximum power point tracking at 40 & DEG;C and 1 sun illumination.The molecular origins of such enhanced stability and device performanceare corroborated by multiscale characterization techniques and modeling,providing insights into the origins of performance and stability enhancements.
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| 8. |
- Krishna, Anurag, et al.
(författare)
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Nanoscale interfacial engineering enables highly stable and efficient perovskite photovoltaics
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 14:10, s. 5552-5562
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Tidskriftsartikel (refereegranskat)abstract
- We present a facile molecular-level interface engineering strategy to augment the long-term operational and thermal stability of perovskite solar cells (PSCs) by tailoring the interface between the perovskite and hole transporting layer (HTL) with a multifunctional ligand 2,5-thiophenedicarboxylic acid. The solar cells exhibited high operational stability (maximum powering point tracking at one sun illumination) with a stabilized T-S80 (the time over which the device efficiency reduces to 80% after initial burn-in) of approximate to 5950 h at 40 degrees C and a stabilized power conversion efficiency (PCE) over 23%. The origin of high device stability and performance is correlated to the nano/sub-nanoscale molecular level interactions between ligand and perovskite layer, which is further corroborated by comprehensive multiscale characterization. These results provide insights into the modulation of the grain boundaries, local density of states, surface bandgap, and interfacial recombination. Chemical analysis of aged devices showed that molecular passivation suppresses interfacial ion diffusion and inhibits the photoinduced I-2 release that irreversibly degrades the perovskite. The interfacial engineering strategies enabled by multifunctional ligands can expedite the path towards stable PSCs.
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