Ultrafast Laser Pulses Induced Insulator–Metal Transition and Multiple Plasmons in Barium Titanate Quantum Dots

Abstract

Recently, all-inorganic perovskite quantum dots have become a hot research topic due to their unique optical response. We have studied barium titanate quantum dots and their hybrid structure consisting silver (Ag) nanowires interacting with ultrafast laser pulses based on time-dependent density functional theory (TDDFT). Through controlling the wavelength and intensity of incident ultrafast light pulses, insulator–metal transition and long-wavelength plasmons can be induced in barium titanate quantum dots. This is because localized field effect breaks the bonds between surrounding oxygen atoms and barium atoms, thus creating metallic patches to form photocurrents. In addition, our results elucidate that Ag nanowires can improve the ultrafast optical responsivity of barium titanate quantum dots especially in the infrared region. Our work theoretically broadens the cognition of all-inorganic perovskite quantum dots interacting with laser and reveals that inorganic perovskite quantum dots have great potential in future applications of optoelectronic devices.

Pressure induced phase transitions of bulk CsGeCl3 and ultrafast laser pulse induced excited-state properties of CsGeCl3 quantum dots

“…In order to further understand the electron transition behavior of the QDs under external laser pulses, we calculate the excited state to investigate the changes in the electron occupied state. The wavelength of 792 nm is employed for ultrafast laser with the intensity of 2.0 eV Å À1 , which has been widely used in previous studies, 27,53 as shown in Fig. 5 (Cm-QDs, ppPv-Pnma-QDs, and I4mm-QDs) at about 2.48 fs, implying that R3m-QDs have a better optical response.…”

“…Perovskite QDs can possess different optical absorption abilities under various wavelength lasers. Here, a wide range of laser wavelengths, 355, 476, 531, 654, and 792 nm, which are frequently employed in experiments and theories, 27 as well as the intensity of 1.5 eV Å À1 are selected shown in Fig. S5(a) (ESI †).…”

“…It may be due to the wavelength of 792 nm being close to the intrinsic frequency of the three CsGeCl 3 QDs, which makes photocarriers achieve higher resonance energy. 27,28,53…”

“…Recently, Lin et al found that BaTiO 3 perovskite QDs have an insulator–metal transition by breaking the bonds of the Ba–O atoms by tuning the ultrafast laser. 27 Moreover, the effects of pressure and ultrafast laser on the oxygen perovskite QDs have been investigated based on the simple ground-state structures and pressure-induced complex structures ( i.e. pPv- Cmcm , ppPv- Pnma , and so on).…”

Structural Phase Transitions and Quantum Dots Regulation of Perovskite Stannates

“…Moreover, the interaction of perovskite QDs with ultrafast laser pulses demonstrates interesting phenomena. Studies of BaTiO 3 QDs discovered an insulator–metal transition under ultrafast laser pulses, which is attributed to the breaking bonds of the Ba–O atoms under a sufficiently strong laser field . In addition, the optical response of perovskite QDs coupled with Ag nanowires shows strong optical absorption, demonstrating that perovskite QDs are great optical gain materials .…”