Abstract
AbstractHere, the phase‐transition from tetragonal to orthorhombic crystal structure of the halide perovskite methylammonium lead iodide single crystal is investigated. Temperature dependent photoluminescence (PL) measurements in the temperature range between 165 and 100 K show complex PL spectra where in total five different PL peaks can be identified. All observed PL features can be assigned to different optical effects from the two crystal phases using detailed PL analyses. This allows to quantify the fraction of tetragonal phase that still occurs below the phase transition temperature. It is found that at 150 K, 0.015% tetragonal phase remain, and PL signatures are observed from quantum confined tetragonal domains, suggesting their size to be about 7–15 nm down to 120 K. The tetragonal inclusions also exhibit an increased Urbach Energy, implying a high degree of structural disorder. The results first illustrate how a careful analysis of the PL can serve to deduce structural information, and second, how structural deviations in halide perovskites have a significant impact on the optoelectronic properties of this promising class of semiconductors.
Highlights
The phase-transition from tetragonal to orthorhombic crystal structure suitable film production methods, proof the halide perovskite methylammonium lead iodide single crystal is investigated
Www.advancedsciencenews.com www.advopticalmat.de analyze the additional peaks in the case of pure tetragonal or orthorhombic crystal phases.[23]. Encouraged by these findings, we investigate in detail the tetragonal-orthorhombic phase transition of a MAPbI3 single crystal using temperature-dependent PL spectroscopy
Regarding the extracted temperature dependent Urbach energies of both phases, we find that the values of Eu,0,tetra and θtetra agree well with the results from Ledinsky et al.,[40] who quantified the temperature dependent Urbach Energies of the tetragonal phase of MAPbI3 thin films on the basis of PL measurements
Summary
Analyze the additional peaks in the case of pure tetragonal or orthorhombic crystal phases.[23]. While the temperature is given from the experimental conditions, the relative intensities and energetic positions of the intrinsic PL peaks, the Urbach energies and the fraction of tetragonal inclusions are optimized to obtain best agreement with the measured spectrum. The experimentally observed shift of peak C saturates at 1.57 eV (Figure 1b), where it becomes indistinguishable from PLtetra, similar to the spectral changes in the modelled spectra for a decreasing fraction of tetragonal phase below 0.1% (Figure 3a). This makes it necessary to allow changing the PL intensity of the tetragonal phase, which is reasonable as the fraction of tetragonal phase decreases. In case of the tetragonal phase below the phase transition temperature, a clear deviation between the expected Urbach energies from Equation (5) and the values obtained from the measured PL spectra becomes obvious
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
