Polymer Amplification to Improve Performance and Stability Towards Semi-Transparent Perovskite Solar Cells Fabrication

Abstract

<p>The performance of methylammonium lead triiodide (CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>) based solar cells depends on its crystallization and controlled microstructure. In spite of its high performance, long-term stability is a paramount factor towards its large area fabrication and potential industrialization. Herein, we have employed poly(vinylidene fluoride−trifluoro ethylene) P(VDF-TrFE) as an additive into a low concentration based perovskite precursor solutions to control the crystallinity and microstructure. Perovskite layers of lower thickness can be derived from low precursor concentration, however it often suffers from severe voids and roughness. Introducing judicious quantities of P(VDF-TrFE) can improve the surface coverage, smoothness as well as reduces the grain boundaries in the perovskite. An array of characterization techniques were utilized to probe the structural, microstructural and spectroscopic properties. Impedance spectra suggests, the P(VDF-TrFE) can improve the carrier lifetimes and reduce the charge transfer resistance, which in turn allows to improve photovoltaic performance. For an optimized concentration of P(VDF-TrFE), the fabricated semi-transparent solar cells yielded power conversion efficiency in excess of 10%, which supersede pristine devices along with improved stability. The device architect and the fabrication technique provide an effective route to fabricate cost effective and visible-light-semi-transparent perovskite solar cells.</p>