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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.

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Schematic description of fabrication procedure of the four different types of OPVs studied in this work (BHJ, p–n, homo p–i–n, and hetero p–i–n devices).DTA and EH-DBTA are deposited through the photoprecursor approach using DTADK and EH-DBTADK as photoprecursor, respectively. Note that the homo p–i–n device contains the same p-type material in the p- and i-layers, while the hetero p–i–n device has different p-type materials between those two layers.
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f2: Schematic description of fabrication procedure of the four different types of OPVs studied in this work (BHJ, p–n, homo p–i–n, and hetero p–i–n devices).DTA and EH-DBTA are deposited through the photoprecursor approach using DTADK and EH-DBTADK as photoprecursor, respectively. Note that the homo p–i–n device contains the same p-type material in the p- and i-layers, while the hetero p–i–n device has different p-type materials between those two layers.

Mentions: The deposition process of organic active layers via the photoprecursor approach is illustrated in Figure 2. The p-layer was prepared by spin-coating of DTADK in chloroform (250 μl, 800 rpm, 30 s) followed by photoirradiation (470 nm LED, 550 mW cm−2, 30 min) to effect the in-situ conversion of DTADK to DTA. The i-layer was deposited in the same manner by using a mixed solution (DTADK:PC71BM or EH-DBTADK:PC71BM). The anthracene-diketone skeleton can be smoothly converted to anthracene even in the presence of PC71BM27. The optimal weight ratio between donor and acceptor in the mixed solution was experimentally determined to be 2:1 (Supplementary Table S1 and Figure S11) which was employed for deposition of i-layers throughout this study. The n-layer was prepared by spin-coating of a chloroform solution of PC71BM (250 μl, 800 rpm, 30 s). The thicknesses of organic layers were controlled by solution concentration (Table 1).


Photoprecursor approach as an effective means for preparing multilayer organic semiconducting thin films by solution processes
Schematic description of fabrication procedure of the four different types of OPVs studied in this work (BHJ, p–n, homo p–i–n, and hetero p–i–n devices).DTA and EH-DBTA are deposited through the photoprecursor approach using DTADK and EH-DBTADK as photoprecursor, respectively. Note that the homo p–i–n device contains the same p-type material in the p- and i-layers, while the hetero p–i–n device has different p-type materials between those two layers.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Schematic description of fabrication procedure of the four different types of OPVs studied in this work (BHJ, p–n, homo p–i–n, and hetero p–i–n devices).DTA and EH-DBTA are deposited through the photoprecursor approach using DTADK and EH-DBTADK as photoprecursor, respectively. Note that the homo p–i–n device contains the same p-type material in the p- and i-layers, while the hetero p–i–n device has different p-type materials between those two layers.
Mentions: The deposition process of organic active layers via the photoprecursor approach is illustrated in Figure 2. The p-layer was prepared by spin-coating of DTADK in chloroform (250 μl, 800 rpm, 30 s) followed by photoirradiation (470 nm LED, 550 mW cm−2, 30 min) to effect the in-situ conversion of DTADK to DTA. The i-layer was deposited in the same manner by using a mixed solution (DTADK:PC71BM or EH-DBTADK:PC71BM). The anthracene-diketone skeleton can be smoothly converted to anthracene even in the presence of PC71BM27. The optimal weight ratio between donor and acceptor in the mixed solution was experimentally determined to be 2:1 (Supplementary Table S1 and Figure S11) which was employed for deposition of i-layers throughout this study. The n-layer was prepared by spin-coating of a chloroform solution of PC71BM (250 μl, 800 rpm, 30 s). The thicknesses of organic layers were controlled by solution concentration (Table 1).

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.


Related in: MedlinePlus