Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 40: Perovskite and Hybrid Photovolatics I (joint session HL/CPP)
HL 40.8: Vortrag
Donnerstag, 4. April 2019, 11:30–11:45, H36
Identification of trap states by photo-induced transient spectroscopy in metal halide perovskites — •Mathias Fischer1, Andreas Baumann2, and Vladimir Dyakonov1 — 1Experimental Physics VI, Julius Maximilian University of Würzburg, 97074 Würzburg — 2Bavarian Center for Applied Energy Research (ZAE Bayern), 97074 Würzburg
Defects in perovskite solar cells ar often related to a reduced device performance. A common method for the characterization of defects in conventional semiconductors is the deep level transient spectroscopy (DLTS). This technique is based on a modulation of the depletion layer width by injecting charge carriers, mostly by applying voltage pulses. Due to electrical field screening in the device, redistribution of mobile ions and relatively low conductivity of organic transport layers, particularly when studying the device at low temperatures, charge carrier injection via voltage pulses is often difficult. This limitation can be mostly overcome by charge carrier injection charges via optical pulses, which enables us to record a rich trap spectrum over the broad temperature range down to 30 K. We apply this technique, which is also known as photo induced-transient spectroscopy (PITS), to perovskites of various compositions and compare the results with complementary techniques, such as thermal admittance spectroscopy and TSC. We show that multiple additional trap states can be observed when optical pulses instead of voltage pulses are used for injection of charges into the device.