Ultrathin Al2O3 interface achieving an 11.46% efficiency in planar n-Si/PEDOT:PSS hybrid solar cells

Hybrid organic-inorganic photovoltaic devices consisting of poly(3,4-etyhlenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) and n-type silicon have recently been investigated for their cost-efficiency and ease of fabrication. We demonstrate that the insertion of an ultrathin Al2O3 layer between n-Si and PEDOT: PSS significantly improves photovoltaic performance in comparison to the conventional interfacial oxide employing SiO2. A power-conversion efficiency of 11.46% was recorded at the optimal Al2O3 thickness of 2.3 nm. This result was achieved based upon increased built-in potential and improved charge collection via the electron blocking effect of Al2O3. In addition, the hydrophilicity enhanced by Al2O3 improved the coating uniformity of the PEDOT: PSS layer, resulting in a further reduction in surface recombination.This work was supported by the International Collaborative Energy Technology R&D Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20168520011370). This work was also supported by the Korea Institute of Energy Technology Evaluation and Planning( KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20153030013200)