title: Coloring Semitransparent Perovskite Solar Cells via Dielectric Mirrors.
abstract: While perovskite-based semitransparent solar cells for window applications show competitive levels of transparency and efficiency compared to organic photovoltaics, the color perception of the perovskite films is highly restricted because band gap engineering results in losses in power conversion efficiencies. To overcome the limitation in visual aesthetics, we combined semitransparent perovskite solar cells with dielectric mirrors. This approach enables one to tailor the device appearance to almost any desired color and simultaneously offers additional light harvesting for the solar cell. In the present work, opto-electrical effects are investigated through quantum efficiency and UV-to-visible spectroscopic measurements. Likewise, a detailed chromaticity analysis, featuring the transmissive and reflective color perception of the device including the mirror, from both sides and in different illumination conditions, is presented and analyzed. Photocurrent density enhancement of up to 21% along with overall device transparency values of up to 31% (4.2% efficiency) is demonstrated for cells showing a colored aesthetic appeal. Finally, a series of simulations emulating the device chromaticity, transparency, and increased photocurrent density as a function of the photoactive layer thickness and the design wavelength of the dielectric mirror are presented. Our simulations and their experimental validation enabled us to establish the design rules that consider the color efficiency/transparency interplay for real applications.
authors.affiliation: Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering, ‡Erlangen Graduate School in Advanced Optical Technologies (SAOT), and §Bavarian Center for Applied Energy Research (ZAE Bayern), Friedrich-Alexander University Erlangen-Nuremberg , 91058 Erlangen, Germany.
authors.forename: César Omar
authors.initials: CO
authors.lastname: Ramírez Quiroz
authors.affiliation: Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering, ‡Erlangen Graduate School in Advanced Optical Technologies (SAOT), and §Bavarian Center for Applied Energy Research (ZAE Bayern), Friedrich-Alexander University Erlangen-Nuremberg , 91058 Erlangen, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Bronnbauer
authors.affiliation: Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering, ‡Erlangen Graduate School in Advanced Optical Technologies (SAOT), and §Bavarian Center for Applied Energy Research (ZAE Bayern), Friedrich-Alexander University Erlangen-Nuremberg , 91058 Erlangen, Germany.
authors.forename: Ievgen
authors.initials: I
authors.lastname: Levchuk
authors.affiliation: Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering, ‡Erlangen Graduate School in Advanced Optical Technologies (SAOT), and §Bavarian Center for Applied Energy Research (ZAE Bayern), Friedrich-Alexander University Erlangen-Nuremberg , 91058 Erlangen, Germany.
authors.forename: Yi
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering, ‡Erlangen Graduate School in Advanced Optical Technologies (SAOT), and §Bavarian Center for Applied Energy Research (ZAE Bayern), Friedrich-Alexander University Erlangen-Nuremberg , 91058 Erlangen, Germany.
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Brabec
authors.affiliation: Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering, ‡Erlangen Graduate School in Advanced Optical Technologies (SAOT), and §Bavarian Center for Applied Energy Research (ZAE Bayern), Friedrich-Alexander University Erlangen-Nuremberg , 91058 Erlangen, Germany.
authors.forename: Karen
authors.initials: K
authors.lastname: Forberich
keywords: Bragg mirror; dielectric mirror; perovskite photovoltaics; room temperature crystallization; semitransparent