TY - JOUR
T1 - Highly near-infrared transparent GeO 2-doped In 2O 3 electrodes for bulk heterojunction organic solar cells
AU - Kang, Sin Bi
AU - Lim, Jong Wook
AU - Na, Seok In
AU - Kim, Han Ki
PY - 2012/12
Y1 - 2012/12
N2 - We report on the characteristics of GeO 2-doped In 2O 3 (IGO) films for use as transparent electrodes in organic solar cells (OSCs). The electrical, optical, and structural properties of IGO electrodes were investigated as a function of RF power and post-annealing conditions. At optimized conditions, the IGO electrode exhibited a low sheet resistance of 14.0 /square, a high optical transmittance of 86.9%, a root mean square roughness of 1.27 nm and a work function of 5.2 eV. In particular, the IGO film showed higher optical transmittance in the near-infrared region due to a lower free carrier concentration and higher mobility than conventional ITO electrodes. The higher Lewis acid strength of the Ge 4 (3.06) dopant, compared to that of a Sn 4 (1.62) dopant, led to higher mobility of the IGO films. In addition, we observed that the strongly oriented (222) grains in the IGO films enhanced carrier mobility and relaxation time. Furthermore, a bulk heterojunction OSC with the optimized IGO anode exhibited a good cell performance with a fill factor of 67.38%, a short circuit current of 8.438 mA/cm 2, an open circuit voltage of 0.606 V, and a power conversion efficiency of 3.443%, which are comparable to OSCs with ITO anodes.
AB - We report on the characteristics of GeO 2-doped In 2O 3 (IGO) films for use as transparent electrodes in organic solar cells (OSCs). The electrical, optical, and structural properties of IGO electrodes were investigated as a function of RF power and post-annealing conditions. At optimized conditions, the IGO electrode exhibited a low sheet resistance of 14.0 /square, a high optical transmittance of 86.9%, a root mean square roughness of 1.27 nm and a work function of 5.2 eV. In particular, the IGO film showed higher optical transmittance in the near-infrared region due to a lower free carrier concentration and higher mobility than conventional ITO electrodes. The higher Lewis acid strength of the Ge 4 (3.06) dopant, compared to that of a Sn 4 (1.62) dopant, led to higher mobility of the IGO films. In addition, we observed that the strongly oriented (222) grains in the IGO films enhanced carrier mobility and relaxation time. Furthermore, a bulk heterojunction OSC with the optimized IGO anode exhibited a good cell performance with a fill factor of 67.38%, a short circuit current of 8.438 mA/cm 2, an open circuit voltage of 0.606 V, and a power conversion efficiency of 3.443%, which are comparable to OSCs with ITO anodes.
KW - GeO -doped In O
KW - Lewis acid strength
KW - Organic solar cells
KW - Transparent electrodes
UR - https://www.scopus.com/pages/publications/84867578196
U2 - 10.1016/j.solmat.2012.07.016
DO - 10.1016/j.solmat.2012.07.016
M3 - Article
AN - SCOPUS:84867578196
SN - 0927-0248
VL - 107
SP - 373
EP - 380
JO - Solar Energy Materials and Solar Cells
JF - Solar Energy Materials and Solar Cells
ER -
