Limits...
Photoprecursor approach as an effective means for preparing multilayer organic semiconducting thin films by solution processes

View Article: PubMed Central - PubMed

ABSTRACT

The vertical composition profile of active layer has a major effect on the performance of organic photovoltaic devices (OPVs). While stepwise deposition of different materials is a conceptually straightforward method for controlled preparation of multi-component active layers, it is practically challenging for solution processes because of dissolution of the lower layer. Herein, we overcome this difficulty by employing the photoprecursor approach, in which a soluble photoprecursor is solution-deposited then photoconverted in situ to a poorly soluble organic semiconductor. This approach enables solution-processing of the p-i-n triple-layer architecture that has been suggested to be effective in obtaining efficient OPVs. We show that, when 2,6-dithienylanthracene and a fullerene derivative PC71BM are used as donor and acceptor, respectively, the best p-i-n OPV affords a higher photovoltaic efficiency than the corresponding p-n device by 24% and bulk-heterojunction device by 67%. The photoprecursor approach is also applied to preparation of three-component p-i-n films containing another donor 2,6-bis(5′-(2-ethylhexyl)-(2,2′-bithiophen)-5-yl)anthracene in the i-layer to provide a nearly doubled efficiency as compared to the original two-component p-i-n system. These results indicate that the present approach can serve as an effective means for controlled preparation of well-performing multi-component active layers in OPVs and related organic electronic devices.

No MeSH data available.


Photo-induced generation of anthracene-based p-type semiconductors from the corresponding α-diketone-type precursors; (a) DTA from DTADK, (b) EH-DBTA from EH-DBTADK.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5384075&req=5

f1: Photo-induced generation of anthracene-based p-type semiconductors from the corresponding α-diketone-type precursors; (a) DTA from DTADK, (b) EH-DBTA from EH-DBTADK.

Mentions: In the following sections, we carefully examine OPVs prepared through the photoprecursor approach. The first part of this report systematically compares solution-processed p–i–n active layers with the corresponding p–n and bulk-heterojunction (BHJ) films employing 2,6-dithienylanthracene (DTA)26 as p-type semiconductor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as n-type semiconductor. It was previously demonstrated that the photoreaction to generate hardly soluble DTA from the well-soluble α-diketone-type photoprecursor DTADK (Figure 1a) readily proceeded in the solid state, and that the thin film of DTA prepared via the photoprecursor approach showed appreciable semiconducting properties14. Among the three different types, the p–i–n architecture affords the best photovoltaic performance associated with favorable electrical properties in the dark. In the second part of this report, we examine ‘hetero p–i–n' devices in which 2,6-bis(5′-(2-ethylhexyl)-(2,2′-bithiophen)-5-yl)anthracene (EH-DBTA, Figure 1b) is employed for the i-layer, while DTA is used in the p-layer. (On the other hand, a device is referred to as ‘homo p–i–n' in the following when both the i- and p-layers are based on the same p-type material.) EH-DBTA is designed, as compared with DTA, to better fulfill the desirable properties for the i-layer material (i.e., high photoabsorption capability and miscibility with the n-type material), and this relatively simple structural modification already leads to nearly twofold enhancement in PCE. These results demonstrate that the photoprecursor approach serves as an effective means for controlled preparation of well-performing multi-component organic active layers.


Photoprecursor approach as an effective means for preparing multilayer organic semiconducting thin films by solution processes
Photo-induced generation of anthracene-based p-type semiconductors from the corresponding α-diketone-type precursors; (a) DTA from DTADK, (b) EH-DBTA from EH-DBTADK.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384075&req=5

f1: Photo-induced generation of anthracene-based p-type semiconductors from the corresponding α-diketone-type precursors; (a) DTA from DTADK, (b) EH-DBTA from EH-DBTADK.
Mentions: In the following sections, we carefully examine OPVs prepared through the photoprecursor approach. The first part of this report systematically compares solution-processed p–i–n active layers with the corresponding p–n and bulk-heterojunction (BHJ) films employing 2,6-dithienylanthracene (DTA)26 as p-type semiconductor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as n-type semiconductor. It was previously demonstrated that the photoreaction to generate hardly soluble DTA from the well-soluble α-diketone-type photoprecursor DTADK (Figure 1a) readily proceeded in the solid state, and that the thin film of DTA prepared via the photoprecursor approach showed appreciable semiconducting properties14. Among the three different types, the p–i–n architecture affords the best photovoltaic performance associated with favorable electrical properties in the dark. In the second part of this report, we examine ‘hetero p–i–n' devices in which 2,6-bis(5′-(2-ethylhexyl)-(2,2′-bithiophen)-5-yl)anthracene (EH-DBTA, Figure 1b) is employed for the i-layer, while DTA is used in the p-layer. (On the other hand, a device is referred to as ‘homo p–i–n' in the following when both the i- and p-layers are based on the same p-type material.) EH-DBTA is designed, as compared with DTA, to better fulfill the desirable properties for the i-layer material (i.e., high photoabsorption capability and miscibility with the n-type material), and this relatively simple structural modification already leads to nearly twofold enhancement in PCE. These results demonstrate that the photoprecursor approach serves as an effective means for controlled preparation of well-performing multi-component organic active layers.

View Article: PubMed Central - PubMed

ABSTRACT

The vertical composition profile of active layer has a major effect on the performance of organic photovoltaic devices (OPVs). While stepwise deposition of different materials is a conceptually straightforward method for controlled preparation of multi-component active layers, it is practically challenging for solution processes because of dissolution of the lower layer. Herein, we overcome this difficulty by employing the photoprecursor approach, in which a soluble photoprecursor is solution-deposited then photoconverted in situ to a poorly soluble organic semiconductor. This approach enables solution-processing of the p-i-n triple-layer architecture that has been suggested to be effective in obtaining efficient OPVs. We show that, when 2,6-dithienylanthracene and a fullerene derivative PC71BM are used as donor and acceptor, respectively, the best p-i-n OPV affords a higher photovoltaic efficiency than the corresponding p-n device by 24% and bulk-heterojunction device by 67%. The photoprecursor approach is also applied to preparation of three-component p-i-n films containing another donor 2,6-bis(5′-(2-ethylhexyl)-(2,2′-bithiophen)-5-yl)anthracene in the i-layer to provide a nearly doubled efficiency as compared to the original two-component p-i-n system. These results indicate that the present approach can serve as an effective means for controlled preparation of well-performing multi-component active layers in OPVs and related organic electronic devices.

No MeSH data available.