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

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.

Flexible CsPbCl3 inorganic perovskite thin-film detectors for real-time monitoring in protontherapy

“…The indication of treated sample means a thermal annealing at 150 °C for 20 h. The plots evidence no major differences depending on the film thickness and thermal treatment in the PL intensity and lineshape. Results are in agreement with those found with similar samples grown on glass substrates [13].…”

“…Taking into consideration geometry and thickness of the device, from these data we get a room temperature resistivity ρ = 1.2 × 10 7 Ω m, in good agreement with Ref. [13].…”

“…Room temperature transmittance spectrum provided a value of the bandgap of 3.0 eV. Room temperature XRD spectra indicate the presence of the correct crystalline phases CsPbCl 3 (ICDD PDF-4+ 18-0366), orthorhombic and tetragonal crystalline phases [13]. SEM analyses reported in [20] evidences a film morphology characterized by a continuous network of several tens of nanometer size crystals with a random distribution of bigger crystals with typical micrometer/sub-micrometer size.…”

“…A detailed electro-optical characterization of CsPbCl 3 thin films, deposited with the same technique on glass, has been reported elsewhere [13,20]. Room temperature transmittance spectrum provided a value of the bandgap of 3.0 eV.…”

“…Recent results on inorganic halide perovskite detectors made of CsPbBr 3 and CsPbCl 3 [5,7] evidenced sensitivity per unit volume for these materials of the same order or even higher than that of silicon, diamond and silicon carbide [11,12], among the most semiconductors used for radiation detection purposes. With respect to CsPbBr 3 , CsPbCl 3 seems to be characterized by a current response as a function of time during exposure to radiation less prone to instabilities due to defects or polarization effects [13][14][15]. Moreover, its high bandgap (3.0 eV) should provide less dark current making it an intrinsically radiation harder material, as in the case of SiC [16].…”