We present solution-based fabrication and characterization of the lead-free perovskite-related methylammonium antimony iodide (CH 3 NH 3 ) 3 Sb 2 I 9 compound. By photothermal deflection spectroscopy (PDS), we determined a peak absorption coefficient α ≈ 10 5 cm −1 and an optical band gap of 2.14 eV for amorphous films of (CH 3 NH 3 ) 3 Sb 2 I 9 . Compared to the related Bi compound, the Sb-perovskite shows no exciton peak in its absorption spectrum. The photoluminescence emission (PL) is observed at 1.58 eV, and the Urbach tail energy of this amorphous compound is E u = 62 meV, indicating a substantial amount of energetic disorder. We fabricate a planar heterojunction solar cell with a (CH 3 NH 3 ) 3 Sb 2 I 9 absorber layer that yields a power conversion efficiency of η ≈ 0.5%, already featuring a decent fill factor (FF) of 55% and open-circuit voltage of 890 mV but low photocurrent densities. The result of this basic study on (CH 3 NH 3 ) 3 Sb 2 I 9 shows that this compound is a possible starting point for further research into Sb-based lead-free perovskite solar cells.L ead-based organic−inorganic hybrid semiconductors like CH 3 NH 3 PbI 3 (MAPI) have shown high potential as efficient absorber materials for single-junction solar cells due to their outstanding optoelectronic properties 1 and the easy and cheap fabrication methods. The power conversion efficiencies of these three-dimensional (3D) perovskite solar cells have increased rapidly up to more than 22% in 2016 2−5 after only 6 years of research starting from the first reported perovskite solar cell with an efficiency of 3.8%. 6 However, the low chemical stability of this lead-based perovskite under ambient air and the toxicity of the heavy metal lead could be obstacles for commercialization. 6−11 The tin analogous perovskite compound CH 3 NH 3 SnI 3 has exhibited moderate conversion efficiencies of up to 6% but is even more unstable under air and moisture because of the rapid oxidation of the Sn 2+ state to the Sn 4+ state. 12−14 Another promising group of materials for lead-free alternatives are the zero-dimensional (0D) Biperovskites A 3 Bi 2 X 9 (e.g., A = Cs + , MA + ; X = I − , Br − ). 15−17 These materials show high band gaps of E g > 1.8 eV, 18,19 which are suitable for tandem or triple solar cells. 20,21 Bismuth is a nontoxic element, and the Bi-based perovskites showed a better chemical stability under ambient atmosphere than the MAPI perovskite. 22 However, the Bi-perovskites also show the signature of excitons in their absorption spectrum that have binding energies in the range of 400 meV. 19,22 This leads to relatively low short-circuit current densities due to insufficient exciton splitting and charge carrier extraction. Bi-perovskitebased solar cells exhibit conversion efficiencies of 1% 22 with a TiO x electron transport layer (ETL) and 0.1% 23 in planar devices with pin-architectures where the exciton splitting at the interfaces is even more critical.In this work, we present the exchange of bismuth by antimony, which is less toxic than P...

Perovskite solar cells have shown a tremendous performance increase in the last years with conversion efficiencies >20%. For the successful application of this technology, an interconnection process is required to create large area solar modules, preferably with the help of precision laser processing. By now, only a few groups have started investigations of this topic. Here, we report on methods and ways to characterize and optimize the perovskite absorber removal process (P2), by means of nanosecond pulsed laser ablation with wavelengths of 355, 532, and 1,064 nm. With short-pulsed lasers, the underlying ablation mechanisms of the perovskite material differ significantly from other thin-film photovoltaic technologies, and the characterization with regards to the formation of contact resistances is indispensible. We show that process optimization based on a morphological evaluation is not sufficient to generate interconnections, without severe influence on the solar module performance.