Electrical and Optical Characterization of CsPbCl3 Films around the High-Temperature Phase Transitions.

Mara Bruzzi,Anna Vinattieri,Nicola Calisi,Naomi Falsini,Matteo Latino

doi:10.3390/nano12030570

Abstract

Large-area CsPbCl3 films in the range 0.1–1.5 μm have been grown by radio frequency (RF)-magnetron sputtering on glass substrates by means of a one-step procedure. Three structural phase transitions have been detected, which are associated with hysteresis behavior in the electrical current when measured as a function of temperature in the range 295–330 K. Similarly, photoluminescence (PL) experiments in the same temperature range bring evidence of a non-monotonic shift of the PL peak. Detailed electrical characterizations evidenced how phase transitions are not influencing detrimentally the electrical transport properties of the films. In particular, the activation energy (0.6–0.8 eV) extracted from the temperature-dependent film resistivity does not appear to be correlated with phase changes. A non-linear trend of the photoconductivity response as a function of a ultra violet (UV) 365 nm light emitting diode (LED) power has been interpreted considering the presence of an exponential tail of intragap defects. Thermally stimulated currents after exposure with the same LED measured from room temperature up to 370 K showed no evidence of trapping effects due to intragap states on the electrical transport properties at room temperature of the films. As a consequence, measured photocurrents at room temperature appear to be well reproducible and stable in time, which are attractive features for possible future applications in photodetection.

Highlights

Metal halide perovskites are semiconducting materials with a general formula AMX3 where A is Cs+, CH3 NH3 + methylammonium, M are metal cations (Pb2+ or Sn2+ ), and X are halide anions (I−, Br−, or Cl− )
Stimulated currents after exposure with the same light emitting diode (LED) measured from room temperature up to 370 K showed no evidence of trapping effects due to intragap states on the electrical transport properties at room temperature of the films
Unlike other inorganic lead halide perovskites, which are commonly realized by solution-based techniques, CsPbCl3 synthesis is more difficult; it has been recently reported that vapor phase deposition, in particular radio frequency (RF) magnetron sputtering, allows for the deposition of nanometric films with a good degree of homogeneity on a large scale and state of the art optical quality [12,13]

Summary

Introduction

Metal halide perovskites are semiconducting materials with a general formula AMX3 where A is Cs+ , CH3 NH3 + methylammonium, M are metal cations (Pb2+ or Sn2+ ), and X are halide anions (I− , Br− , or Cl− ) This material class has received enormous attention in the scientific community recently due to breakthroughs in optoelectronic applications, mainly in photovoltaics [1,2], photodetectors [3,4,5,6,7], light emission [8,9], and lasing [10]. Unlike other inorganic lead halide perovskites, which are commonly realized by solution-based techniques, CsPbCl3 synthesis is more difficult; it has been recently reported that vapor phase deposition, in particular RF magnetron sputtering, allows for the deposition of nanometric films with a good degree of homogeneity on a large scale and state of the art optical quality [12,13].

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Conclusion