Se powder

Cadmium oxide (CdO), Se powder, Octadecane (ODE) (90%), oleic acid (OA), Trioctylphosphine (TOP) were purchased from Sigma-Aldrich for CdSe preparation. Degussa P25-TiO₂ nanocrystallite was supplied by Evonik Aeroxide. All of the chemicals were used without any further purification.

The sample was prepared by PLD followed by selenization. A highly pure MoO₃ target of approximately 20 mm diameter was placed in a rotating target holder. The target was exposed to a laser beam for several minutes to remove surface contaminants. A sapphire substrate approximately 20 × 20 mm² was placed in a rotating substrate holder. The distance between the substrate and target was 25 cm. The chamber pressure was 25 mTorr, established by flowing high pure argon (Ar) at 10 sccm. A KrF excimer laser (λ = 248 nm, CompexPro 102 F) with 20 ns pulse width, 200 mJ/cm² power density, 3 Hz repetition rate deposited thin MoO₃ films in 45 s. The substrate temperature during deposition was 700 °C. The as-deposited MoO₃ films were then converted to MoSe₂ by selenization in a two-zone hot-wall furnace. Se powder (Sigma Aldrich, 99.99%) was placed in the low temperature zone at 450 °C, and the film located in the high temperature zone at 900 °C. A mixture of Ar and H₂ were employed as carrier gases to transport Se vapor from the colder to the hotter zone. H₂ also assist in reducing MoO₃.

Single crystals of AuTe₂Se_4/3 were grown using the self-flux method. Total 2–4 g starting materials with high purity Au powder (99.99%, Sigma Aldrich), Te powder (99.999%, Sigma Aldrich), and Se powder (99.99%, Sigma Aldrich) were stoichiometrically weighted and sealed in an evacuated silica tube in high vacuum (10⁻⁵ mbar) and subsequently mounted into a muffle furnace. The furnace was heated up to 800 °C in 40 h and dwelled 10 h. Afterward, the furnace was slowly cooled down to 450 °C in 4 days and then shut down. Separated crystals from ingot are generally thin with maximum planar size 4 × 1 mm². The single crystals of AuTe₂Se_4/3 were ribbon shape with shining mirror-like surfaces.

All the chemicals such as chloroplatinic acid, Se powder, hexamethylenetetramine, and NaBH₄ were purchased from Sigma-Aldrich for the synthesis of PtSe₂ nanosheets.

1-Octadecene (90%), oleic acid (90%), CdO
(≥99.99%), Se powder (100 mesh, 99.99%), trichloroethylene
(anhydrous, ≥99%), 1-hexanethiol (97%), and 1-octadecanethiol
(98%) were purchased from Sigma-Aldrich. 1-Decanethiol (96%) and 1-tetradecanethiol
(94%) were purchased from Alfa Aesar. 1H,1H,2H,2H-Perfluoro-1-hexanethiol
(97%) was purchased from Synquest Laboratories. Hydrochloric acid
(37%) and HPLC grade hexane were purchased from Bio-Lab.

1-Octadecene
(90%), oleic acid (90%), CdO
(≥99.99%), Se powder (100 mesh, 99.99%), trichloroethylene
(anhydrous, ≥ 99%), 1-butanethiol (99%), 1-pentanethiol (98%),
1-hexanethiol (97%), 1-heptanethiol (98%), 1-octanethiol (≥98.5%),
1-nonanethiol (98%), 1-decanethiol (96%), 2-methyl-1-butanethiol (99%),
3-methyl-1-butanethiol (97%), 2-ethyl-1-hexanethiol (97%), 2-methyl-1-hexanoic
acid (98%), 5-methyl-1-hexanoic acid (98%), 4-methyl-1-octanoic acid
(98%), 4-ethyl-1-octanoic acid (98%), 4-methyl-1-nonanoic acid (99%),
LiAlH₄, p-toluenesulfonyl chloride (99%),
thiourea (99%), toluene-d₈ (99.6% D),
and chloroform-d₁ (99.8% D) were purchased
from Sigma-Aldrich, Alfa Aesar, or Acros Organics.