Dr. Kien Wen Sun, Professor, National Chiao Tung University, Taiwan.

Speech Title: Highly Efficient Back-junction PEDOT:PSS/n-Si Hybrid Solar Cell with Omnidirectional Antireflection Structures

Abstract: Several recent studies on organic/semiconductor heterojunction solar cells have been designed to augment the power conversion efficiency (PCE) by spin coating a thin PEDOT: PSS polymer layer onto silicon/gallium arsenide wafers. Investigations on techniques that can improve the performance of hybrid PEDOT: PSS/semiconductor solar cells have been widely conducted. The limited efficiency of current PEDOT:PSS/Si solar cells is due to the location of the heterojunction at the front side, which results in a parasitic light absorption within the organic material and a shading loss from the front contacts. In addition, the rear surface of these front-junction solar cells is commonly poorly passivated. In this presentation, we report the hybrid solar cells based on the “BackPEDOT” concept. BackPEDOT cells with Si NWs and those with random pyramid (RP) AR structures were compared. The BackPEDOT solar cells with Si NW AR structures in front of the device were fabricated using the MACE method. These cells demonstrated an optimum PCE of 14.5%. The proposed back-contact solar cell structure can minimize the parasitic absorption in PEDOT: PSS and avoid the poor contact at the PEDOT:PSS/Si NWs/anode interfaces. Cells with Si NW AR structures also showed omnidirectional light-trapping characteristics over those with RP structures. These cells also maintained a constant PCE with the increase of incident angles to approximately 60°.