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Low temperature, solution-processed alumina for organic solar cells
This content has been downloaded from IOPscience. Please scroll down to see the full text. 2013 Nanotechnology 24 484010 (http://iopscience.iop.org/0957-4484/24/48/484010) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 169.230.243.252 This content was downloaded on 26/08/2014 at 07:19
Please note that terms and conditions apply.
IOP PUBLISHING
NANOTECHNOLOGY
Nanotechnology 24 (2013) 484010 (8pp)
doi:10.1088/0957-4484/24/48/484010
Low temperature, solution-processed alumina for organic solar cells Jun Peng, Qijun Sun, Zhichun Zhai, Jianyu Yuan, Xiaodong Huang, Zhiming Jin, Kunyang Li, Suidong Wang, Haiqiao Wang and Wanli Ma1 Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People’s Republic of China E-mail: [email protected]
Received 3 June 2013, in final form 24 July 2013 Published 6 November 2013 Online at stacks.iop.org/Nano/24/484010 Abstract In this work, we have reported for the first time a facile route for developing solution-processed Al2 O3 film at a greatly reduced processing temperature and studied its applications in producing inverted polymer solar cells (PSCs). These PSCs using Al2 O3 thin film as the electron-extraction layer demonstrated improved diode characteristics and achieved a 20% higher power conversion efficiency than devices using the conventional ZnO buffer layer. Furthermore, the low temperature processing of the Al2 O3 film makes it compatible with fabrication of flexible organic electronic devices based on plastic substrates. S Online supplementary data available from stacks.iop.org/Nano/24/484010/mmedia (Some figures may appear in colour only in the online journal)
1. Introduction
although it possesses numerous advantages, such as low cost, non-toxicity, high chemical stability and low interface state densities [22], likely due to its difficult fabrication process. The traditional deposition techniques for Al2 O3 films are atomic layer deposition (ALD) [20, 23], thermal evaporation [21], plasma-enhanced atomic layer deposition (PEALD) [24] and magnetron sputtering [25], which are, however, not suitable for low cost and large scale production. To date, only very few works on solution-processed Al2 O3 buffer layers in solar cells have been reported, in which a high temperature annealing of the Al2 O3 films was a requirement [26–30]. For example, in 2003, Palomares et al used a solution-processed Al2 O3 blocking layer in dye sensitized solar cells and a high temperature annealing at 435 ◦ C for 20 min was performed to complete the thermal conversion of the precursor into Al2 O3 [26]. In 2012, Ozawa et al developed a new Al2 O3 sol–gel processing which again required a 1 h thermal annealing at 500 ◦ C [29]. Evidently, the high temperature process of annealing during the fabrication of the solution-processed Al2 O3 films is not compatible with the flexible organic electronic devices based on plastic substrates. Therefore it will be of great interest to develop new techniques for producing solution-processed Al2 O3 films under low temperature.
Solution-processible semiconducting materials have shown great potential in organic photovoltaics (OPVs) [1–3] due to advantages like low manufacturing cost, high production throughput, area/shape flexible processes and light weight. The organic/electrode interface has been proven to be crucial to device performance [4, 5]. In polymer solar cells (PSCs), poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been widely used as an anode interlayer [6]. However, the acidic and hygroscopic PEDOT causes the degradation of normal structured devices by slowly etching the indium tin oxide substrate (ITO). Hence an inverted solar cell architecture has been adopted to avoid the use of PEDOT [7–9], in which a transparent and chemically stable electron-extraction interlayer is required to modify the ITO work function. So far, several promising metal oxide materials, such as ZnO [10–14], TiOx [15–17] and Cs2 CO3 [18, 19] have been used in solar cells as such electron-extraction layers between the ITO and active layers. Unfortunately, compared to these extensively investigated materials, Al2 O3 has been rarely studied as a buffer layer used in OPVs [20, 21] 1 Author to whom any correspondence should be addressed.
0957-4484/13/484010+08$33.00
1
c 2013 IOP Publishing Ltd Printed in the UK & the USA
Nanotechnology 24 (2013) 484010
J Peng et al
In this work, we have reported a new facile and costeffective synthesis route for developing solution-processed Al2 O3 films as electron-extraction layers in PSCs. The optimal device performance can be obtained under low temperature (
Search
Collections
Journals
About
Contact us
My IOPscience
Low temperature, solution-processed alumina for organic solar cells
This content has been downloaded from IOPscience. Please scroll down to see the full text. 2013 Nanotechnology 24 484010 (http://iopscience.iop.org/0957-4484/24/48/484010) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 169.230.243.252 This content was downloaded on 26/08/2014 at 07:19
Please note that terms and conditions apply.
IOP PUBLISHING
NANOTECHNOLOGY
Nanotechnology 24 (2013) 484010 (8pp)
doi:10.1088/0957-4484/24/48/484010
Low temperature, solution-processed alumina for organic solar cells Jun Peng, Qijun Sun, Zhichun Zhai, Jianyu Yuan, Xiaodong Huang, Zhiming Jin, Kunyang Li, Suidong Wang, Haiqiao Wang and Wanli Ma1 Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People’s Republic of China E-mail: [email protected]
Received 3 June 2013, in final form 24 July 2013 Published 6 November 2013 Online at stacks.iop.org/Nano/24/484010 Abstract In this work, we have reported for the first time a facile route for developing solution-processed Al2 O3 film at a greatly reduced processing temperature and studied its applications in producing inverted polymer solar cells (PSCs). These PSCs using Al2 O3 thin film as the electron-extraction layer demonstrated improved diode characteristics and achieved a 20% higher power conversion efficiency than devices using the conventional ZnO buffer layer. Furthermore, the low temperature processing of the Al2 O3 film makes it compatible with fabrication of flexible organic electronic devices based on plastic substrates. S Online supplementary data available from stacks.iop.org/Nano/24/484010/mmedia (Some figures may appear in colour only in the online journal)
1. Introduction
although it possesses numerous advantages, such as low cost, non-toxicity, high chemical stability and low interface state densities [22], likely due to its difficult fabrication process. The traditional deposition techniques for Al2 O3 films are atomic layer deposition (ALD) [20, 23], thermal evaporation [21], plasma-enhanced atomic layer deposition (PEALD) [24] and magnetron sputtering [25], which are, however, not suitable for low cost and large scale production. To date, only very few works on solution-processed Al2 O3 buffer layers in solar cells have been reported, in which a high temperature annealing of the Al2 O3 films was a requirement [26–30]. For example, in 2003, Palomares et al used a solution-processed Al2 O3 blocking layer in dye sensitized solar cells and a high temperature annealing at 435 ◦ C for 20 min was performed to complete the thermal conversion of the precursor into Al2 O3 [26]. In 2012, Ozawa et al developed a new Al2 O3 sol–gel processing which again required a 1 h thermal annealing at 500 ◦ C [29]. Evidently, the high temperature process of annealing during the fabrication of the solution-processed Al2 O3 films is not compatible with the flexible organic electronic devices based on plastic substrates. Therefore it will be of great interest to develop new techniques for producing solution-processed Al2 O3 films under low temperature.
Solution-processible semiconducting materials have shown great potential in organic photovoltaics (OPVs) [1–3] due to advantages like low manufacturing cost, high production throughput, area/shape flexible processes and light weight. The organic/electrode interface has been proven to be crucial to device performance [4, 5]. In polymer solar cells (PSCs), poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been widely used as an anode interlayer [6]. However, the acidic and hygroscopic PEDOT causes the degradation of normal structured devices by slowly etching the indium tin oxide substrate (ITO). Hence an inverted solar cell architecture has been adopted to avoid the use of PEDOT [7–9], in which a transparent and chemically stable electron-extraction interlayer is required to modify the ITO work function. So far, several promising metal oxide materials, such as ZnO [10–14], TiOx [15–17] and Cs2 CO3 [18, 19] have been used in solar cells as such electron-extraction layers between the ITO and active layers. Unfortunately, compared to these extensively investigated materials, Al2 O3 has been rarely studied as a buffer layer used in OPVs [20, 21] 1 Author to whom any correspondence should be addressed.
0957-4484/13/484010+08$33.00
1
c 2013 IOP Publishing Ltd Printed in the UK & the USA
Nanotechnology 24 (2013) 484010
J Peng et al
In this work, we have reported a new facile and costeffective synthesis route for developing solution-processed Al2 O3 films as electron-extraction layers in PSCs. The optimal device performance can be obtained under low temperature (
