Microstructure-driven annihilation effects and dispersive excited state dynamics in solid-state films of a model sensitizer for photon energy up-conversion applications

Abstract

Bimolecular processes involving exciton spin-state interactions gain attention for their deployment as wavelength-shifting tools. Particularly triplet-triplet annihilation induced photon energy up-conversion (TTA-UC) holds promise to enhance the performance of solar...

Multi-wavelength excited triplet–triplet upconversion microcrystals based on hot-band excitation for optical information encryption

“…In this work, the multi-wavelength excited UC performance of PtOEP/DPA microcrystals, which are one of the most widely used TTA-UC dye pairs, based on hot-band excitation mode was systematically investigated. [26][27][28][29][30] In addition to the commonly used excitation wavelength of 532 nm, this TTA-UC microcrystalline system also achieved 443 nm blue UC emission under excitation at 589, 635, 655, and 671 nm, with a maximum anti-Stokes shift of 0.95 eV. Moreover, the maximum anti-Stokes shift in the solution can reach 1.04 eV.…”

“…As one of the most commonly used TTA-UC dye molecule pairs, PtOEP and DPA are still regarded as a classic model system and have been applied in various TTA-UC research studies. [26][27][28][29][30] However, when using selective excitation of the sensitizer PtOEP at 532 nm (zero vibrational energy level in the ground state, S 0 n 0 ), the resulting green-to-blue TTA-UC has a small anti-Stokes shift of 0.55 eV. To increase the anti-Stokes shift of TTA-UC, excitation of PtOEP at the hot-band vibrational energy levels in the ground state (S 0 n t ) was conducted using diode lasers of 589 nm, 635 nm, 655 nm and 671 nm, respectively.…”

Unexpected Performance of a Bifunctional Sensitizer/Activator Component for Photon Energy Management via Upconversion

“… 34 Recent work on PtOEP blended with the blue-light emitting poly(fluorene-2-octyl) (PFO) derivative proposed how TTA reactions in PtOEP activate the S 1 state of PFO within the 100 fs time scale. 35 Similarly, the TTA-induced activation of the Pt-centered state of PtOEP-K may sensitize the observed DPA TTA-UC luminescence ( Figure 4 a).…”

“…In those systems the generation of upconverted luminescence is not involving a TET step but it is facilitated by a TTA-activated metal-centered d – d * state in PtOEP . Recent work on PtOEP blended with the blue-light emitting poly­(fluorene-2-octyl) (PFO) derivative proposed how TTA reactions in PtOEP activate the S 1 state of PFO within the 100 fs time scale . Similarly, the TTA-induced activation of the Pt-centered state of PtOEP-K may sensitize the observed DPA TTA-UC luminescence (Figure a).…”