TY - JOUR
T1 - Solution processed WO3 layer for the replacement of PEDOT:PSS layer in organic photovoltaic cells
AU - Choi, Hana
AU - Kim, Bongsoo
AU - Ko, Min Jae
AU - Lee, Doh Kwon
AU - Kim, Honggon
AU - Kim, Sung Hyun
AU - Kim, Kyungkon
N1 - Funding Information:
This research was supported by New and Renewable Energy Program through the Korea Institute of Energy Technology Evaluation and Planning (KETEP) funded by the Ministry of Knowledge Economy (MKE) ( 008NPV08J010000 ), the Pioneer Research Center Program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology ( 2009-0081500 ) and Industry Resource Technology Development Program (Contract: 10034648) from Korea Ministry of Knowledge and Economy.
PY - 2012/6
Y1 - 2012/6
N2 - Tungsten oxide layer is formed uniformly by a sol-gel technique on top of indium tin oxide as a neutral and photo-stable hole extraction layer (HEL). The solution processed tungsten oxide layer (sWO3) is fully characterized by UV-Vis, XPS, UPS, XRD, AFM, and TEM. Optical transmission of ITO/sWO 3 substrates is nearly identical to ITOs. In addition, the sWO 3 layer induces nearly ohmic contact to P3HT as PEDOT:PSS layer does, which is determined by UPS measurement. In case that an optimized thickness (∼10 nm) of the sWO3 layer is incorporated in the organic photovoltaic devices (OPVs) with a structure of ITO/sWO3/P3HT:PCBM/ Al, the power conversion efficiency (PCE) is 3.4%, comparable to that of devices utilizing PEDOT:PSS as HEL. Furthermore, the stability of OPV utilizing sWO3 is significantly enhanced due to the air- and photo-stability of the sWO3 layer itself. PCEs are decreased to 40% and 0% of initial values, when PEDOT:PSS layers are exposed to air and light for 192 h, respectively. In contrast, PCEs are maintained to 90% and 87% of initial PCEs respectively, when sWO3 layers are exposed to the same conditions. Conclusively, we find that solution processed tungsten oxide layers can be prepared easily, act as an efficient hole extraction layer, and afford a much higher stability than PEDOT:PSS layers.
AB - Tungsten oxide layer is formed uniformly by a sol-gel technique on top of indium tin oxide as a neutral and photo-stable hole extraction layer (HEL). The solution processed tungsten oxide layer (sWO3) is fully characterized by UV-Vis, XPS, UPS, XRD, AFM, and TEM. Optical transmission of ITO/sWO 3 substrates is nearly identical to ITOs. In addition, the sWO 3 layer induces nearly ohmic contact to P3HT as PEDOT:PSS layer does, which is determined by UPS measurement. In case that an optimized thickness (∼10 nm) of the sWO3 layer is incorporated in the organic photovoltaic devices (OPVs) with a structure of ITO/sWO3/P3HT:PCBM/ Al, the power conversion efficiency (PCE) is 3.4%, comparable to that of devices utilizing PEDOT:PSS as HEL. Furthermore, the stability of OPV utilizing sWO3 is significantly enhanced due to the air- and photo-stability of the sWO3 layer itself. PCEs are decreased to 40% and 0% of initial values, when PEDOT:PSS layers are exposed to air and light for 192 h, respectively. In contrast, PCEs are maintained to 90% and 87% of initial PCEs respectively, when sWO3 layers are exposed to the same conditions. Conclusively, we find that solution processed tungsten oxide layers can be prepared easily, act as an efficient hole extraction layer, and afford a much higher stability than PEDOT:PSS layers.
KW - Device stability
KW - Hole extraction layer
KW - Metal oxide
KW - Organic photovoltaic cells
UR - http://www.scopus.com/inward/record.url?scp=84859905267&partnerID=8YFLogxK
U2 - 10.1016/j.orgel.2012.01.033
DO - 10.1016/j.orgel.2012.01.033
M3 - Article
AN - SCOPUS:84859905267
SN - 1566-1199
VL - 13
SP - 959
EP - 968
JO - Organic Electronics
JF - Organic Electronics
IS - 6
ER -
