Polymer Amplification to Improve Performance and Stability toward Semitransparent Perovskite Solar Cells Fabrication

The performance of methylammonium lead triiodide (CH₃NH₃PbI₃)-based solar cells depends on the crystallization and controlled microstructure. Despite their high performance, long-term stability is a paramount factor toward large area fabrication and potential industrialization. Herein, poly(vinylidene fluoride–trifluoro ethylene) (P(VDF-TrFE)) is used as an additive into a low concentration–based perovskite precursor solution to control the crystallinity and microstructure. Perovskite layers of lower thicknesses are derived from low precursor concentration, however, they often suffer from severe voids and roughness. Introducing judicious quantities of P(VDF-TrFE) improves the surface coverage and smoothness, as well as reduce the grain boundaries in the perovskite. An array of characterization techniques are used to probe the structural, microstructural, and spectroscopic properties. Impedance spectra suggest that the P(VDF-TrFE) can improve the carrier lifetime and reduce the charge transfer resistance, which in turn allows improvment of photovoltaic performance. For an optimized concentration of P(VDF-TrFE), the fabricated semitransparent solar cells yield a power conversion efficiency in excess of 10%, which supersedes pristine devices, along with improved stability. The device architecture and the fabrication technique provide an effective route to fabricate cost effective and visible-light-semitransparent perovskite solar cells.