Rubidium antimony halides are a promising low toxic alternative to organo-lead halide perovskites as photovoltaic material. In this contribution, we systematically investigate the influence of varying the bromide to iodide ratio on the structural, optical, and photovoltaic properties of Rb3Sb2­Br9–x I x (x = 0–9). Single crystal data reveal that all compounds crystallize in a 2D-layered monoclinic crystal structure. Sequential substitution of iodide with the smaller bromide does not change the crystal system; however, increasing the bromide content results in a shrinkage of the unit cell as well as in a blue shift of the absorption onset, increasing the band gap from 2.02 to 2.46 eV. Whereas the photovoltaic properties of bromide rich compounds are limited due to a preferential orientation of the layered structure parallel to the substrate, which is detrimental to charge transport, solar cells with Rb3Sb2I9 as absorber material display power conversion efficiencies of 1.37%. Moreover, the devices exhibit low hysteresis properties and are stable for more than 150 days stored under inert atmosphere.

A perylene-based acceptor (PMI-FF-PMI), consisting of two perylene monoimide (PMI) units bridged with a dihydroindeno[1,2 b]fluorene molecule was developed as a potential non-fullerene acceptor (NFA) for organic solar cells (OSCs)....

Perovskite solar cells with a planar p-i-n device structure offer easy processability at low temperatures, suitable for roll-to-roll fabrication on flexible substrates. Herein we investigate different hole transport layers (solution processed NiO x , sputtered NiO x , PEDOT:PSS) in planar p-i-n perovskite solar cells using the triple cation lead halide perovskite Cs 0.08 (MA 0.17 FA 0.83 ) 0.92 Pb(I 0.83 Br 0.17 ) 3 as absorber layer. Overall, reproducible solar cell performances with power conversion efficiencies up to 12.8% were obtained using solution processed NiO x as hole transport layer in the devices. Compared to that, devices with PEDOT:PSS as hole transport layer yield efficiencies of approx. 8.4%. Further improvement of the fill factor was achieved by the use of an additional zinc oxide nanoparticle layer between the PC 60 BM film and the Ag electrode.

Solar cells based on the novel triple cation tin perovskite MA0.75FA0.15PEA0.1SnI3 exhibit PCEs of 5.0% and notably good stability over more than 5000 hours.