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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

Out of plane XRD diffractograms of SVA treated DPP(TBFu)2:MIF and DPP(TBFu)2:PC61BM thin films on ITO/PEDOT:PSS.
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f5: Out of plane XRD diffractograms of SVA treated DPP(TBFu)2:MIF and DPP(TBFu)2:PC61BM thin films on ITO/PEDOT:PSS.

Mentions: The XRD diffractograms of the DPP:MIF and DPP:PC61BM films are shown in Fig. 5 and show a peak at 2θ = 6.19° and 6.09°, respectively, corresponding to an inter-plane spacing of 14.3 Å and 14.5 Å, respectively, which is characteristic of pure DPP(TBFu)2, as seen in previous studies2728. The average crystallite size for DPP(TBFu)2 in the annealed DPP(TBFu)2:MIF film, calculated using the Scherrer equation, was 17.9 nm36, which is very similar to what we calculated for DPP(TBFu)2 blended with PC61BM, 17.8 nm. There was, however, a difference in the overall crystallite volume observed between DPP(TBFu)2:MIF and DPP(TBFu)2:PC61BM films, with the latter having a higher volume (Fig. 5). No peaks corresponding to MIF were observed. The similarities observed between the AFM and XRD data of DPP(TBFu)2:MIF and DPP(TBFu)2:PC61BM BHJ films help explain the high hole mobility and JSC observed in optimum DPP(TBFu)2:MIF devices, especially if we consider what was observed by Viterisi et al. for DPP(TBFu)2 blended with DPM fullerene derivatives, for example, where the morphology of the active layer, as well as the crystallinity of DPP(TBFu)2, was significantly affected by the DPM fullerene26.


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)

Out of plane XRD diffractograms of SVA treated DPP(TBFu)2:MIF and DPP(TBFu)2:PC61BM thin films on ITO/PEDOT:PSS.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: Out of plane XRD diffractograms of SVA treated DPP(TBFu)2:MIF and DPP(TBFu)2:PC61BM thin films on ITO/PEDOT:PSS.
Mentions: The XRD diffractograms of the DPP:MIF and DPP:PC61BM films are shown in Fig. 5 and show a peak at 2θ = 6.19° and 6.09°, respectively, corresponding to an inter-plane spacing of 14.3 Å and 14.5 Å, respectively, which is characteristic of pure DPP(TBFu)2, as seen in previous studies2728. The average crystallite size for DPP(TBFu)2 in the annealed DPP(TBFu)2:MIF film, calculated using the Scherrer equation, was 17.9 nm36, which is very similar to what we calculated for DPP(TBFu)2 blended with PC61BM, 17.8 nm. There was, however, a difference in the overall crystallite volume observed between DPP(TBFu)2:MIF and DPP(TBFu)2:PC61BM films, with the latter having a higher volume (Fig. 5). No peaks corresponding to MIF were observed. The similarities observed between the AFM and XRD data of DPP(TBFu)2:MIF and DPP(TBFu)2:PC61BM BHJ films help explain the high hole mobility and JSC observed in optimum DPP(TBFu)2:MIF devices, especially if we consider what was observed by Viterisi et al. for DPP(TBFu)2 blended with DPM fullerene derivatives, for example, where the morphology of the active layer, as well as the crystallinity of DPP(TBFu)2, was significantly affected by the DPM fullerene26.

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