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All-optical THz wave switching based on CH 3 NH 3 PbI 3 perovskites

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ABSTRACT

Hybrid structures of silicon with organic–inorganic perovskites are proposed for optically controllable switching of terahertz (THz) waves over a broad spectral range from 0.2 to 2THz. A 532-nm external laser was utilized to generate photoexcited free carriers at the devices and consequentially to control the terahertz amplitude modulation, obtaining a depth of up to 68% at a laser irradiance of 1.5 W/cm2. In addition, we compared the performances from three types of perovskite devices fabricated via different solution processing methods and suggested a stable and highly efficient THz switch based on a one-step processing. By this we demonstrated the possibility of perovskites as THz wave switching devices in addition to photovoltaics.

No MeSH data available.


Freqeuncy-dependent complex constants extracted by THz-TDS based on the Gabor WT and the Drude model.(a) Complex dielectric constants of bare Si and the corresponding complex conductivities of (b) CHP, (c) CBdrp, and (d) IFF devices under various irradiances.
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f4: Freqeuncy-dependent complex constants extracted by THz-TDS based on the Gabor WT and the Drude model.(a) Complex dielectric constants of bare Si and the corresponding complex conductivities of (b) CHP, (c) CBdrp, and (d) IFF devices under various irradiances.

Mentions: To investigate the modulation mechanism in detail, we deduced the optical constants of the perovskite/Si devices via THz-TDS under various laser irradiances. The complex dielectric constant was obtained by comparing the THz transmission at the perovskite/Si devices to bare Si. We extracted the refractive index and the absorption coefficient from the time-frequency spectrogram based on the Gabor wavelet transform (Gabor WT)29 to calculate the complex dielectric constant, εcomplex = ε1 + iε2, as shown in Fig. 4(a). The real and imaginary parts of dielectric constant were 10.86 and 0.10 at 0.75 THz, respectively, which are higher than those of 9.9 and 0.01 reported by Li et al.30. This can be explained by the fact that the photo-doping on Si by external laser pump in our experiment changed the dielectric property31.


All-optical THz wave switching based on CH 3 NH 3 PbI 3 perovskites
Freqeuncy-dependent complex constants extracted by THz-TDS based on the Gabor WT and the Drude model.(a) Complex dielectric constants of bare Si and the corresponding complex conductivities of (b) CHP, (c) CBdrp, and (d) IFF devices under various irradiances.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121641&req=5

f4: Freqeuncy-dependent complex constants extracted by THz-TDS based on the Gabor WT and the Drude model.(a) Complex dielectric constants of bare Si and the corresponding complex conductivities of (b) CHP, (c) CBdrp, and (d) IFF devices under various irradiances.
Mentions: To investigate the modulation mechanism in detail, we deduced the optical constants of the perovskite/Si devices via THz-TDS under various laser irradiances. The complex dielectric constant was obtained by comparing the THz transmission at the perovskite/Si devices to bare Si. We extracted the refractive index and the absorption coefficient from the time-frequency spectrogram based on the Gabor wavelet transform (Gabor WT)29 to calculate the complex dielectric constant, εcomplex = ε1 + iε2, as shown in Fig. 4(a). The real and imaginary parts of dielectric constant were 10.86 and 0.10 at 0.75 THz, respectively, which are higher than those of 9.9 and 0.01 reported by Li et al.30. This can be explained by the fact that the photo-doping on Si by external laser pump in our experiment changed the dielectric property31.

View Article: PubMed Central - PubMed

ABSTRACT

Hybrid structures of silicon with organic–inorganic perovskites are proposed for optically controllable switching of terahertz (THz) waves over a broad spectral range from 0.2 to 2THz. A 532-nm external laser was utilized to generate photoexcited free carriers at the devices and consequentially to control the terahertz amplitude modulation, obtaining a depth of up to 68% at a laser irradiance of 1.5 W/cm2. In addition, we compared the performances from three types of perovskite devices fabricated via different solution processing methods and suggested a stable and highly efficient THz switch based on a one-step processing. By this we demonstrated the possibility of perovskites as THz wave switching devices in addition to photovoltaics.

No MeSH data available.