Plasmonic backscattering enhancement for inverted polymer solar cells

The enhanced performance of inverted polymer solar cells enabled by a plasmonic backscattering effect is reported upon. To produce localized surface plasmons (LSPs) at the rear anode, thermally deposited Ag nanoparticles (NPs) are embedded in the MoO3 hole extraction layer. Upon optimizing the MoO3/Ag NPs/MoO3 sandwich structure, enhanced light harvesting is achieved via plasmonic backscattering into the photoactive layer of poly(3-hexylthiophene)/[6,6]-phenyl-C61 butyric acid methyl ester (P3HT:PCBM), resulting in an increase in photocurrent without sacrificing electrical properties, and similar to 20% enhancement in power conversion efficiency, of 4.32% Vs. 3.61% of the reference device. The performance improvement of the inverted PSCs is ascribed to the enhanced light absorption as a result of the light backscattering as well as the excitation of LSPs induced by Ag NPs embedded in the MoO3 layer. The present method provides a promising pathway for the fabrication of high-efficiency PSCs in an inexpensive and scalable way.