Royal Society of Chemistry praises HZB team’s paper on hybrid perovskite structures

T-x phase diagram has been created for MAPb(I,Br)<sub>3</sub> for the first time. It was revealed that the phase transition temperature of the iodine-rich mixed crystals drops as iodine content increases.

T-x phase diagram has been created for MAPb(I,Br)3 for the first time. It was revealed that the phase transition temperature of the iodine-rich mixed crystals drops as iodine content increases. © RSC Advances

For the 10th anniversary collection of its journal, the Royal Society of Chemistry (RSC) selected a paper published by a team from HZB. The paper from HZB is described as one of the most important contributions in the field of solar energy in recent years. The journal praised 23 selected papers that had been often cited or downloaded, and which offered a valuable advantage for further research. 

The HZB paper focuses on the systematic characterisation of hybrid perovskites containing mixed halides (MAPb(I,Br)3). The samples of the mixed crystals were produced in powder form using a solvent-based synthesis method. The research team from HZB’s Department Structure and Dynamics of Energy Materials (SE-ASD) showed that the crystal structure of the mixed crystal compounds is temperature dependent. As the materials go through different phase transitions, they form either a tetragonal or a cubic perovskite structure depending on the temperature and chemical composition. Now, a comprehensive T-x phase diagram has been created for this solid solution series for the first time. It was revealed that the phase transition temperature of the iodine-rich mixed crystals drops as iodine content increases, which stabilises the cubic perovskite structure at room temperature.

For their temperature-dependent in-situ experiments, HZB’s team used the DIFFRACTION end station of the BESSY II beamline KMC-2. They additionally determined the band gap energy and studied the optoelectronic properties of these perovskite compounds (among other things using photoluminescence spectroscopy).

The results led to a fundamental structural characterisation of these mixed halide perovskite compounds. Although the study was based on powder-form materials, the insights gained on the temperature-dependent behaviour of these hybrid halide perovskites can be now be applied to thin-film materials like those used to create absorbers for thin-film solar cells.     

The paper was authored by Frederike Lehmann as part of her doctoral thesis in the graduate school HyPerCell. Her thesis was supervised by Prof. Dr. Susan Schorr and Dr. Alexandra Franz from the HZB Department Structure and Dynamics of Energy Materials and by Prof. Dr. Andreas Taubert from Potsdam University. “The paper was an excellent team achievement, and we are delighted that the RSC chose to write about us,” says Susan Schorr.

Click here for the RSC Advances Anniversary Collection “Solar Energy

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