Ultrafast Broadband Nonlinear Optical Response in Co-Doped Sb2Se3 Nanofilms at Near-Infrared

Abstract

Transition metal-doped Sb2Se3 has become a heated topic caused by the strong nonlinear optical response and the ultrafast response time at high laser excitation. In this paper, the Co-doped Sb2Se3 with different doping amount (0.5, 1.0, and 1.5 W) nanofilms were prepared by magnetron sputtering technology, and the nonlinear behavior of Co-doped Sb2Se3 nanofilms at near infrared were systematically studied. The results of the femtosecond Z-Scan experiment indicate that the Co-doped Sb2Se3 nanofilms exhibit broadband nonlinear response properties owing to the free carrier absorption, the Kerr refraction, the two-photon absorption, and the free carrier refraction. The nonlinear absorption coefficients of Co-doped Sb2Se3 nanofilms are from 3.0 × 10−9 to 2.03 × 10−8 m/ W under excitation at 800, 980, and 1,030 nm, and the nonlinear refractive index of the Co-doped Sb2Se3 nanofilms is from 4.0 × 10−16 to -3.89 × 10−15 m2/ W at 800, 980, and 1,030 nm. More importantly, Co-doped Sb2Se3 (1.5 W) nanofilm exhibits ultrafast carrier absorption (<1 ps) and a stronger transient absorption intensity of ΔOD > 6.3. The Co-doping content can controllably tune the crystalline degree, the ultrafast carrier absorption, the intensity of the reverse saturation absorption, the broadband nonlinear optical response, and the carrier relaxation time of Co-doped Sb2Se3 nanofilms. These results are sufficient to support their applications in broadband nonlinear photonic devices.

Design of n-i-p and p-i-n Sb2Se3 solar cells: role of band alignment

“…According to [11], the bandgap of Sb 2 Se 3 falls within the range of 1.1-1.3 eV, while the carrier mobility has been reported to be in the range of 50-300 cm 2 (V s) −1 [12]. In addition, the carrier lifetime has been reported to be on the order of nanoseconds to microseconds, while the optical absorption coefficient is around 10 4 -10 5 cm −1 [12]. Moreover, Sb 2 Se 3 is an abundant and low-cost material, which makes it an attractive option for the large-scale production of solar cells [12].…”

“…In addition, the carrier lifetime has been reported to be on the order of nanoseconds to microseconds, while the optical absorption coefficient is around 10 4 -10 5 cm −1 [12]. Moreover, Sb 2 Se 3 is an abundant and low-cost material, which makes it an attractive option for the large-scale production of solar cells [12]. In this context, the use of Sb 2 Se 3 as an absorber material in solar cells has been extensively investigated by researchers worldwide, where over a few years, the power conversion efficiency (PCE) of Sb 2 Se 3 -based solar cells has significantly increased from less than 3% to approximately 10.57% [13][14][15][16], demonstrating the significant potential of Sb 2 Se 3 as a material for PV applications.…”

Covalent functionalization of Sb2S3 with poly(N-vinylcarbazole) for solid-state broadband laser protection

“…These materials show a femtosecond broadband NLO response due to the free carrier refraction, the Kerr refraction, the two-photon absorption and the free carrier absorption. 10 A major disadvantage of Sb 2 S 3 is its poor solubility in common organic solvents, implying poor solution-processability.…”