TY - JOUR
T1 - ITO-free inverted polymer solar cells with ZnO:Al cathodes and stable top anodes
AU - Sio, Antonietta De
AU - Chakanga, Kambulakwao
AU - Sergeev, Oleg
AU - von Maydell, Karsten
AU - Parisi, Jürgen
AU - Hauff, Elizabeth Von
PY - 2012/3
Y1 - 2012/3
N2 - We report on the application of ZnO:Al as the transparent conductive oxide in high performance inverted polymer solar cells. We show that the optimized inverted architecture, which does not contain low work function metals or water-based transport layers, can be employed without sacrificing device efficiency. The widely studied P3HT:PCBM donor–acceptor system was chosen for the active layer. ZnO:Al layers were produced by dc-magnetron sputtering on glass substrates and used as the cathode. The thickness of ZnO:Al was optimized to achieve a low sheet resistance while maintaining high transmission. The resulting ZnO:Al layers were smoother than the reference ITO samples, and the active layers could be processed directly onto ZnO:Al without employing additional buffer layers. The structure of the top anodic contact was also optimized. Initial devices with an Au layer demonstrated poor results, and device performance improved when a MoO3/Ag anode was used. Control devices in the standard forward structure using commercial ITO coated glass substrates were compared to the ZnO:Al based cells. Higher photocurrents were obtained in the inverted structures than in the ITO-based solar cells due to the higher transmittance of ZnO:Al in the spectral range where the blend absorbs.
AB - We report on the application of ZnO:Al as the transparent conductive oxide in high performance inverted polymer solar cells. We show that the optimized inverted architecture, which does not contain low work function metals or water-based transport layers, can be employed without sacrificing device efficiency. The widely studied P3HT:PCBM donor–acceptor system was chosen for the active layer. ZnO:Al layers were produced by dc-magnetron sputtering on glass substrates and used as the cathode. The thickness of ZnO:Al was optimized to achieve a low sheet resistance while maintaining high transmission. The resulting ZnO:Al layers were smoother than the reference ITO samples, and the active layers could be processed directly onto ZnO:Al without employing additional buffer layers. The structure of the top anodic contact was also optimized. Initial devices with an Au layer demonstrated poor results, and device performance improved when a MoO3/Ag anode was used. Control devices in the standard forward structure using commercial ITO coated glass substrates were compared to the ZnO:Al based cells. Higher photocurrents were obtained in the inverted structures than in the ITO-based solar cells due to the higher transmittance of ZnO:Al in the spectral range where the blend absorbs.
KW - Polymer solar cell
KW - Inverted solar cell
KW - ZnO:Al
KW - ITO-free
KW - PEDOT:PSS free
U2 - 10.1016/j.solmat.2011.10.015
DO - 10.1016/j.solmat.2011.10.015
M3 - Article
VL - 98
SP - 52
EP - 56
JO - SOLAR ENERGY MATERIALS AND SOLAR CELLS
JF - SOLAR ENERGY MATERIALS AND SOLAR CELLS
SN - 0927-0248
ER -