Silver nanoparticle plasmonic effects on hole-transport material-free mesoporous heterojunction perovskite solar cells

Localized surface plasmon resonance excitation of noble metal nanoparticles (NPs) under light illumination can be incorporated to effectively improve light-harvesting devices. The present study aims at silver nanoparticles (Ag NPs) plasmonic effects on the photovoltaic characteristics of mesoporous hetrojunction perovskite solar cells. Ag NPs were embedded into a compact TiO2 layer, which commonly acts as hole blocking layer in mesoporous perovskite solar cells. An optimum concentration of Ag NPs loaded on colt pact TiO2:Ag-NPs films of hole-transport material-free (HTM-free(perovskite solar cells leads to more than 30% enhancement in power conversion efficiency of the fabricated cells compared with what Ag nanoparticle-free samples can do. The improved performance can be attributed to the scattering effect from the incorporated Ag-NPs, which effectively extends the optical pathway of incident light that increases the photon absorption of the photoactive perovskite layer. In addition to the modulated optical properties of HTM-free perovskite solar cells, electrochemical impedance spectroscopy measurements show that electron transport time at the interfacial layer of TiO2 and the photovoltaic perovskite layer decreases as a result of frequency response improvement in the photoanode interface. (C) 2016 Elsevier Ltd. All rights reserved.