Implicit Tandem Organic–Inorganic Hybrid Perovskite Solar Cells Based on Internal Dye Sensitization: Robotized Screening, Synthesis, Device Implementation, and Theoretical Insights

Abstract

Low-dimensional hybrid perovskite materials offer significantly improved stability as well as an extensive compositional space to explore. However, they suffer from poor photovoltaic performance as compared to the 3D perovskite materials because of poor charge-transport properties. Herein, we present the concept of internal dye-sensitized hybrid perovskite compounds involving five novel low-dimensional perovskite-type materials 1 – 5 incorporating triarylmethane, phenazinium and near-infrared (NIR) cyanine cationic dyes, respectively. The synthesis characterization and theoretical analysis of these compounds are presented. Theoretical calculations provide interesting insights into the effects of these dyes on the band structure of the low-dimensional anionic metal-halides and especially highlight compound 1 as a promising photovoltaic candidate. Solar cell investigation of devices based on 1 were conducted. The results show an average power conversion efficiency (PCE) of about 0.1%, which is among the highest reported for a 1D material despite the use of undoped Spiro-OMeTAD as the hole-transport material (HTM). Incident photon-to-electron efficiency (IPCE) spectra confirm the contribution of the dye to the overall photocurrent of the solar cell. Moreover, examination of solar cell devices based on the bismuth-based compound 5 resulted in PCEs in the range of 0.1%. This illustrates the potential of this concept to be exploited for lead-free photovoltaics. Finally automated robotized screening of low-dimensional hybrid perovskite materials through the screening robot PROTEUS has emerged as a powerful tool in the search for novel perovskite-like materials. Our work highlights that the use of cationic dyes could induce interesting sensitizing properties to low-dimensional metal-halide chains and may therefore provide inspiration and new design strategies for the synthesis of new lead-free photovoltaic materials

A Peierls Transition in Long Polymethine Molecular Wires: Evolution of Molecular Geometry and Single-Molecule Conductance

“…During this study, we used single-crystal X-ray diffraction to determine the structures of 11 polymethine dyes (see Supporting Information). To the best of our knowledge, there have been no previous reports of crystal structures of cyanines as long as Cy9 + or Cy11 + , but several structures have been reported for cyanines similar to Cy7 + . ,− Before discussing these structures, we must specify how BLA is quantified. In general, BLA is defined as the difference in length between consecutive bonds along a π-conjugated chain.…”

Zero-Dimensional Lead-Free Halide with Indirect Optical Gap and Enhanced Photoluminescence by Sb Doping

“…Organic–inorganic metal halides (OIMHs) have attracted tremendous attention as a new series of outstanding semiconductor materials due to the high absorption coefficient, high charge carrier mobility, low defect tolerance, and easily tunable band gaps . Thanks to their unique optoelectronic properties, OIMHs exhibit promising applications for devices including solar cells, − lasers, , photodetectors, , and light-emitting diodes (LEDs). − In recent years, OIMHs have also been revealed as promising luminescent materials for solid-state lighting with broad band emission and high photoluminescence quantum yields (PLQYs). , Given that the instability of the three-dimensional structure as well as the toxicity of Pb strongly hinders the practical applications, low-dimensional lead-free OIMHs with hydrophobic organic ligands emerge as the stable and environmentally friendly luminous materials. , Furthermore, considering that the dimensional reduction strategy significantly enhances the structural quantum confinement at the molecular level, zero-dimensional (0D) OIMHs can emit intense visible light with large Stokes shifts and long lifetime of photogenerated excitions. − Several 0D lead-free OIMH groups with different metal cations including Bi 3+ , Sb 3+ , Zn 2+ , and Mn 2+ have been reported in previous literature, and the related photoluminescence has been investigated. − 0D OIMHs with mixed metal cations such as (bmpy) 9 [ZnCl 4 ] 2 [Pb 3 Cl 11 ] and (bmpy) 9 [SbCl 5 ] 2 [Pb 3 Cl 11 ] (bmpy: 1-butyl-1-methylpyrrolidinium) were also synthesized, which show various emission colors and high PLQY. , …”

Ionic Liquid Synthesis of (Et3S)[Ag4I5] – A Structure Containing Basket‐Like Silver‐Iodide Cages with Ag22+ Pairs

“…Compound 1 can be regarded as a wide‐bandgap semiconductor with a bandgap of about 3.7 eV. The inclusion of light‐absorbing guest molecules in the structure thus offers the possibility to tune the optoelectronic properties, like recently shown for halide perovskite materials [24] …”