Unraveling Ultralong Phosphorescence in Ar2PO(H): N(O)→ σ*(P-C)Transitions in Ar2PO(H) Stabilize Triplet States Better than n(P)→ σ*(P-C)in Ar3P

Jena, S and Muhammed Munthasir, AT and Thilagar, P (2023) Unraveling Ultralong Phosphorescence in Ar2PO(H): N(O)→ σ*(P-C)Transitions in Ar2PO(H) Stabilize Triplet States Better than n(P)→ σ*(P-C)in Ar3P. In: Journal of Physical Chemistry C, 127 (20). pp. 9918-9930.

PDF jou_phy_che_C_127-20_9918 -9930_2023.pdf - Published Version Restricted to Registered users only Download (6MB) | Request a copy

Abstract

Herein, we report the crystallization-induced persistent room-temperature phosphorescence (CIpRTP) characteristics of simple diarylphosphine oxides 1, 2, and 3. Under ambient conditions, crystalline solids of 1, 2, and 3 show photoluminescence (PL) lifetime of more than 100 ms. At 77 K, they exhibit a PL lifetime of nearly a second. Replacing one of the aryl moieties in Ar3P-O with hydrogen creates more space for intermolecular interactions in Ar2P-O (H); consequently, the latter shows better PL quantum yield (PLQY) than the former. The PLQYs of these compounds are tuned systematically by varying the steric perturbation around the phosphorus center. Detailed analysis of the crystal structure of these compounds revealed that the intermolecular interactions play a crucial role in stabilizing the triplet state in the solid state and bestowing them with CIpRTP. Thin films of these compounds do not show pRTP, further affirming that the intermolecular interactions indeed play a crucial role in stabilizing the triplet state. In the solution state, these compounds show ultraviolet fluorescence (λem ≈ 305 nm) with a small Stokes shift of ∼3200 cm-1 and narrow bandwidth (FWHM: 37, 35, and 33 nm for 1, 2, and 3, respectively). The calculated SOC («T1|Ĥ|S0») matrix element for 1, 2, and 3 is significantly lower than the value estimated for triarylphosphines; thus, the former show ultralong phosphorescence compared to the latter. Furthermore, the n(O) → σ*(P-C) transition plays a crucial role in controlling the optical features in these compounds.

Item Type:	Journal Article
Publication:	Journal of Physical Chemistry C
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to the American Chemical Society.
Keywords:	Crystal structure, Ambient conditions; Crystalline solids; Crystals structures; Intermolecular interactions; Photoluminescence lifetime; Photoluminescence quantum yields; Room temperature phosphorescence; Simple++; Sterics; Triplet state, Phosphorescence
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	13 Jul 2023 09:45
Last Modified:	13 Jul 2023 09:45
URI:	https://eprints.iisc.ac.in/id/eprint/82416

Actions (login required)

View Item