Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 28: Organic Semiconductors 1
HL 28.6: Talk
Thursday, September 8, 2022, 11:00–11:15, H34
Photoexcited charge carrier and spin dynamics in methylammonium lead bromide doped by magnetic transition metals — •Stanislav Bodnar1, Jonathan Zerhoch1,2, Andrii Shcherbakov1,2, Shangpu Liu1,2, Lissa Eyre1, and Felix Deschler1,2 — 1Walter Schottky Institut, Physik Department, Technische Universität München, Garching, Germany — 2Heidelberg University, Heidelberg, Germany
One of the most challenging tasks for LED applications is emitting 100% polarized light from the device. Typically, this is achieved by introducing an additional layer of polarization filter which leads to losing half of the light intensity. To overcome this issue, one has to find a system with a high degree of photoluminescence (PL) polarization. A promising approach here is using magnetic metal doping in combination with a highly efficient semiconductor. We have chosen to use transient absorption (TA) spectroscopy at cryogenic temperatures to investigate changes in the optical properties induced by magnetic metal doping in CH3NH3PbBr3 since it gives spectral information about the energies of electronic states and dynamic properties of the photoexcited carriers. We find a change in the main ground state bleach (GSB) peak position in doped CH3NH3PbBr3, which depends on the transition metal used. The main GSB peak of pure CH3NH3PbBr3 at 4 K is at 2.32 eV. Doping CH3NH3PbBr3 with Mn leads to a shift of the main peak to lower energies by 0.04 eV and 0.08 eV, respectively. The modifications of the TA spectra are associated with changes in the bandgap energy, which is the result of doping-induced lattice expansion.