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Increased efficiency in small molecule organic solar cells through the use of a 56-π electron acceptor--methano indene fullerene.

Ryan JW, Matsuo Y - Sci Rep (2015)

Bottom Line: The challenge, however, is to prevent the typical concomitant decrease in the short circuit current density (JSC) when using a higher LUMO fullerene.In this communication, we address the issue by applying methano indene fullerene, MIF, a bis-functionalised C60 fullerene that has a LUMO level 140 mV higher than PCBM, in solution processed SMOSCs with a well known small molecule donor, DPP(TBFu)2.MIF-based devices show an improved VOC of 140 mV over PC61BM and only a small decrease in the JSC, with the PCE increasing to 5.1% (vs. 4.5% for PC61BM).

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

ABSTRACT
Organic solar cells (OSCs) offer the possibility of harnessing the sun's ubiquitous energy in a low-cost, environmentally friendly and renewable manner. OSCs based on small molecule semiconductors (SMOSCs)--have made a substantial improvement in recent years and are now achieving power conversion efficiencies (PCEs) that match those achieved for polymer:fullerene OSCs. To date, all efficient SMOSCs have relied on the same fullerene acceptor, PCBM, in order to achieve high performance. The use of PCBM however, is unfavourable due to its low lying LUMO level, which limits the open-circuit voltage (VOC). Alternative fullerene derivatives with higher lying LUMOs are thus required to improve the VOC. The challenge, however, is to prevent the typical concomitant decrease in the short circuit current density (JSC) when using a higher LUMO fullerene. In this communication, we address the issue by applying methano indene fullerene, MIF, a bis-functionalised C60 fullerene that has a LUMO level 140 mV higher than PCBM, in solution processed SMOSCs with a well known small molecule donor, DPP(TBFu)2. MIF-based devices show an improved VOC of 140 mV over PC61BM and only a small decrease in the JSC, with the PCE increasing to 5.1% (vs. 4.5% for PC61BM).

No MeSH data available.


Related in: MedlinePlus

Device architecture and molecular structure of DPP and MIF together with their HOMO-LUMO levels.
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f1: Device architecture and molecular structure of DPP and MIF together with their HOMO-LUMO levels.

Mentions: Here we apply a 56-π bis-functionalised fullerene (MIF), where one adduct is an indene group and the other is methanediyl group9, in SMOSCs using the well known DPP(TBFu)2 as a donor27, with the aim of improving the VOC due to the higher LUMO of this 56-π fullerene (−3.66 eV vs. 3.80 eV for PC61BM)9. The indene group provides for a good “alkyl chain-free” solubilizing group while the methanediyl adduct is the smallest possible adduct a fullerene can be functionalized with. This combination of adducts was chosen to reduce the conjugation of the fullerene in a manner that provides adequate solubility without using bulky adducts or adducts containing long alkyl chain substituents that could prevent, or at least limit, the formation of well-ordered DPP(TBFu)2 domains. Fig. 1 shows the device architecture and molecular structures and energy levels of DPP(TBFu)2 and MIF. We found that MIF does indeed improve VOC and maintains high JSC values, the latter being explained by the device morphology and DPP(TBFu)2 crystallinity, which are very similar to DPP(TBFu)2:PC61BM, as evidenced by atomic force microscopy (AFM) and X-ray diffraction (XRD).


Increased efficiency in small molecule organic solar cells through the use of a 56-π electron acceptor--methano indene fullerene.

Ryan JW, Matsuo Y - Sci Rep (2015)

Device architecture and molecular structure of DPP and MIF together with their HOMO-LUMO levels.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321161&req=5

f1: Device architecture and molecular structure of DPP and MIF together with their HOMO-LUMO levels.
Mentions: Here we apply a 56-π bis-functionalised fullerene (MIF), where one adduct is an indene group and the other is methanediyl group9, in SMOSCs using the well known DPP(TBFu)2 as a donor27, with the aim of improving the VOC due to the higher LUMO of this 56-π fullerene (−3.66 eV vs. 3.80 eV for PC61BM)9. The indene group provides for a good “alkyl chain-free” solubilizing group while the methanediyl adduct is the smallest possible adduct a fullerene can be functionalized with. This combination of adducts was chosen to reduce the conjugation of the fullerene in a manner that provides adequate solubility without using bulky adducts or adducts containing long alkyl chain substituents that could prevent, or at least limit, the formation of well-ordered DPP(TBFu)2 domains. Fig. 1 shows the device architecture and molecular structures and energy levels of DPP(TBFu)2 and MIF. We found that MIF does indeed improve VOC and maintains high JSC values, the latter being explained by the device morphology and DPP(TBFu)2 crystallinity, which are very similar to DPP(TBFu)2:PC61BM, as evidenced by atomic force microscopy (AFM) and X-ray diffraction (XRD).

Bottom Line: The challenge, however, is to prevent the typical concomitant decrease in the short circuit current density (JSC) when using a higher LUMO fullerene.In this communication, we address the issue by applying methano indene fullerene, MIF, a bis-functionalised C60 fullerene that has a LUMO level 140 mV higher than PCBM, in solution processed SMOSCs with a well known small molecule donor, DPP(TBFu)2.MIF-based devices show an improved VOC of 140 mV over PC61BM and only a small decrease in the JSC, with the PCE increasing to 5.1% (vs. 4.5% for PC61BM).

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

ABSTRACT
Organic solar cells (OSCs) offer the possibility of harnessing the sun's ubiquitous energy in a low-cost, environmentally friendly and renewable manner. OSCs based on small molecule semiconductors (SMOSCs)--have made a substantial improvement in recent years and are now achieving power conversion efficiencies (PCEs) that match those achieved for polymer:fullerene OSCs. To date, all efficient SMOSCs have relied on the same fullerene acceptor, PCBM, in order to achieve high performance. The use of PCBM however, is unfavourable due to its low lying LUMO level, which limits the open-circuit voltage (VOC). Alternative fullerene derivatives with higher lying LUMOs are thus required to improve the VOC. The challenge, however, is to prevent the typical concomitant decrease in the short circuit current density (JSC) when using a higher LUMO fullerene. In this communication, we address the issue by applying methano indene fullerene, MIF, a bis-functionalised C60 fullerene that has a LUMO level 140 mV higher than PCBM, in solution processed SMOSCs with a well known small molecule donor, DPP(TBFu)2. MIF-based devices show an improved VOC of 140 mV over PC61BM and only a small decrease in the JSC, with the PCE increasing to 5.1% (vs. 4.5% for PC61BM).

No MeSH data available.


Related in: MedlinePlus