Investigation of Morphology‐Controlled Ultrafast Relaxation Processes of Aggregated Porphyrin. Issue 19 (15th September 2020)

• Record Type: Journal Article
• Authors: Mondal, Bodhisatwa; Bera, Rajesh; Ghosh, Srijon; Nayak, Sandip K.; Patra, Amitava
• Is Part Of: Chemphyschem. Volume 21:Issue 19(2020)
• Page Start: 2196
• Page End: 2205
• Publication Date: 2020-09-15
• Subjects: decay dynamics -- femtosecond transient absorption spectroscopy -- porphyrins -- rods and flakes -- self-assemblies; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.202000482
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: Here, we have synthesized rod and flake shaped morphology of porphyrin aggregates from 5, 10, 15, 20‐tetra (4‐ n ‐octyloxyphenyl) porphyrin (4‐opTPP) molecule which are evident from scanning electron microscopy (SEM). The formation of J‐type aggregation is evident from steady state and time‐resolved fluorescence spectroscopic studies. Ultrafast transient absorption spectroscopic studies reveal that the excited state lifetime is controlled by the morphology and the time constant for S1 →S0 relaxation changes from 3.05 ps to 744 ps with changing the shape from rod to flake, respectively. In spite of similar exciton coupling energy in both the aggregates, the flake shaped aggregates undergo a faster exciton relaxation process and the non‐radiative relaxation channels are found to depend on the shape of aggregates. The fundamental understanding of morphology controlled ultrafast relaxation processes of aggregated porphyrin is important for designing efficient light harvesting devices. Abstract : Shape controls the relaxation dynamics of porphyrin aggregates.