Search for a full or partial Catalog Number, CAS Number or description
Your favorites Quick Order Form
Your cart is empty.
Contact Strem

'Product Blog'

Trioctylphosphine (TOP) – An Important Precursor For Designing II−VI, III−V, and IV−VI Quantum Dots

TOP enables sulfonation, salination, telluration and phosphonation of metal cations in Quantum Dot preparations

Trioctylphosphine (TOP 15-6655), a long-chain alkylphosphine with a lone electron pair on the phosphorus atom, serves as a common reagent in the chemical synthesis of II−VI, III−V, and IV−VI nanocrystals.  Examples include CdE (E=S, Se, Te), InP, PbS, and PbSe quantum dots (QDs) [1]. It’s well known that long alkyl chains can prevent nanoparticles from aggregating.  The long chain can also stabilize uncontrolled growth and stabilize the nanoparticle in solution.  Furthermore, the pair of electrons on the phosphorus forms strong bonds with selenium (93-3416; 34-0090), sulfur (93-1616; 93-1617; 93-1618) and tellurium (93-5222; 52-5200; 93-5220) powders [1], forming the TOP−E anion precursors for salination, sulfonation and telluration of metal counterparts. More recently, it has been reported that QDs can be phosphonated by mixing them with white phosphorus (P4) and TOP [1, 2].


Fig. 1. Model reaction of metal precursors (e.g. Me2Cd) with (C8H17)3P-E (TOP-E) in TOPO

TOP−E precursors can be prepared either with direct dissolution of elemental powders  E (E=S, Se, Te, P…) in TOP (mp 30°C) at temperatures around 80-90°C, or by dissolving TOP/E mixture in polymeric solvents with high boiling points (e.g. oleic acid (OA; mp 17°C; 06-4010); octadecylamine (ODA; mp 50-52°C); and octadecene (ODE; mp 17-18°C).

Furthermore, to save time and material when optimizing reaction conditions Strem offers pre-prepared trioctylphosphine sulfide TOP-S (15-7550 CYTOP® 505;) and trioctylphosphine selenide TOP-Se (15-6659 CYTOP® 504; 15-6657) that are ready for use.

TOP−E precursors are compatible with trioctylphosphine oxide (TOPO, 15-6660, 15-6661).  TOPO is one of the best solvents for high temperature preparation of various nanocomposites (please review our blog on TOPO).

TOPO and TOP–E stabilized QDs are lipophilic materials that are synthesized by rapid mixing of precursors by injection into a hot (usually over 300°C) solution. Resulting surfactant ligands (TOPO and/or TOP–E) enable QDs stabilization in nonpolar solvents. Therefore, for further functionalization of particles, these ligands undergo a ligand exchange process with hydrophilic ligands (e.g. PEG) creating quantum dots re-dispersible in polar solvents [3-6].

For other long chain alkylphosphonic acids, used as common reagents in the chemical, and colloidal, synthesis of nanoparticles (including QDs), please review the following product numbers:

96-1525 Long-Chain n-Alkylphosphonic Acid Kit

15-0958 n-Decylphosphonic acid, min. 97% (6874-60-8)

15-1835 n-Dodecylphosphonic acid, min. 97% DDPA (5137-70-2)

15-2400 n-Hexadecylphosphonic acid, min. 97% HDPA (4721-17-9)

15-2410 n-Hexylphosphonic acid, min. 97% HPA (4721-24-8)

15-3510 n-Octadecylphosphonic acid, min. 97% ODPA (4724-47-4)

15-3520 n-Octylphosphonic acid, min. 97% OPA (4724-48-5)

15-5145 n-Tetradecylphosphonic acid, min. 97% TDPA (4671-75-4)



  1. ACS Nano, 2017, 11, 10373.
  2. Chem. Mater., 2017, 29, 4236.
  3. Langmuir, 2017, 33, 8239.
  4. Chem. Mater., 2013, 25, 1155.
  5. J. Phys. Chem. B, 2005, 109, 7012.
  6. Nano Lett., 2003, 3, 503.


Products mentioned in this blog:
06-4010: Oleic acid, 99% (112-80-1)
15-6655: Tri-n-octylphosphine, min. 97% TOP (4731-53-7)
15-6659: Trioctylphosphine selenide min. 80% (20612-73-1)
15-6660: Trioctylphosphine oxide, min. 90% TOPO (78-50-2)
15-6661: Trioctylphosphine oxide, 99% TOPO (78-50-2)
15-6665: Tri-n-octylphosphine, min. 90% (4731-53-7)
15-7550: Trioctylphosphine sulfide, CYTOP® 505 (2551-53-3)
15-7615: Tributylphosphine sulfide/tributylphosphine (50:50 mixture), CYTOP® 506 (3084-50-2)
34-0090: Selenium powder (99.99%) (7782-49-2)
52-5200: Tellurium powder (99.9%) (13494-80-9)
93-1616: Sulfur (99.999%) (7704-34-9)
93-1617: Sulfur powder, precipitated, purified (7704-34-9)
93-1618: Sulfur powder, sublimed (99+%) (7704-34-9)
93-3416: Selenium powder (99.5%) (7782-49-2)
93-5220: Tellurium powder (99.999%) (13494-80-9)
93-5222: Tellurium powder (99.8%) (13494-80-9)
96-1525: Long-Chain n-Alkylphosphonic Acid Kit

Related Materials:
Nanomaterials Booklet
Materials for Energy Applications
Phosphines for Colloidal Synthesis of Semiconducting Quantum Dots
Trioctylphosphine oxide (TOPO): An Essential Component for Quantum Dot Preparation




Return to Product Blog

Request the Strem Chemicals Catalog Bulk Quote Request Get Quarterly Updates by Email