4:45 PM - 5:15 PM
[13p-B7-8] c-Si/PEDOT:PSS heterojunction solar cells
Keywords:Solar cells, Silicon, Conjugated polymer
Among several conjugated polymers, poly(3,4-ethylenedioxythiphene):poly(styrene sulfonate)(PEDOT:PSS) has recently proved to be one of the most promising candidates for transparent hole-transporting layer, which has been applied for organic thin-film solar cells and electroluminescence devices. So far we have investigated the n-type CZ c-Si(thickness, 300 μm)/PEDOT:PSS heterojunction solar cells with several polar solvents such as methanol (MeOH) alone or MeOH/ethylene glycol(EG) cosolvent. The power conversion efficiency η increased from 6-7% for the pristine to 10 and 11% using methanol alone and MeOH/EG cosolvent, respectively. The improvement of the performance is mainly attributed to the increased short circuit current Jsc, fill factor FF and decreased series resistance of diode together with the increase of EQE in entire wavelength region. η increased to 13.5% by adjusting the solvent concentration, film thickness of PEDOT:PSS, and a resistivity of c-Si substrate without using p-n junction, and transparent conductive oxide (TCO) layer. These findings originate from the uniaxial optical anisotropy, i.e., metallic character in-plane, whereas a dielectric property in out-of-plane, although it’s degree depend on the solvent, deposition method. Thus, conductive PEDOT:PSS works as a transparent hole transporting layer as well as a transparent conductive layer. Among several parameters, an open-circuit-voltage Voc increased from 0.55 to 0.61V by adjusting a resistivity of 0.1-0.3 Ω·cm. η further increased to 15.4% using TiO2 or MoO3 as an AR coating layer. We also attempt the fabrication of solar cell module using four-inch size c-Si wafer. In this paper, we will demonstrate the state-of-art c-Si/PEDOT:PSS heterojunction solar cells for efficient solar cell module with improved stability for air storage and light soaking.