Thienyl/phenyl bay-substituted perylenebisimides: Intersystem crossing and application as heavy atom-free triplet photosensitizers

Sadiq F., Wang Z., Hou Y., Zhao J., ELMALI A., Escudero D., ...Daha Fazla

DYES AND PIGMENTS, cilt.184, 2021 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 184
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1016/j.dyepig.2020.108708
  • Dergi Adı: DYES AND PIGMENTS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Delayed fluorescence, Intersystem crossing, Perylenebisimide, Thiophene, Triplet state, SINGLET OXYGEN GENERATION, ACTIVATED DELAYED FLUORESCENCE, DENSITY-FUNCTIONAL THEORY, PHOTON UP-CONVERSION, EXCITED-STATE, CHARGE-TRANSFER, ELECTRON-TRANSFER, ENERGY-LEVELS, BASIS-SETS, PERYLENE
  • Ankara Üniversitesi Adresli: Evet

Özet

Different perylene-3,4:9,10-bis(dicarboximide) (abbreviated as perylenebisimides, or simply PBI) compounds (MT-PBI, DT-PBI, MP-PBI and DP-PBI) with thienyl and phenyl substituents at the bay position were prepared to study the effect of substitution on the photophysical properties, especially the intersystem crossing (ISC) efficacy. We found that the derivative with a monothienyl substituent (MT-PBI) shows efficient ISC (singlet oxygen quantum yield Phi(Delta) = 72%) and longer triplet state lifetime (tau(T) = 64.4 mu s) as compared to reference compounds (derivative with monophenyl substituent at bay position, MP-PBI, Phi(Delta) = 23% and tau(T) = 48.5 mu s). Theoretical computations reveal that the ISC efficiency is dependent on the magnitude of the spin orbit couplings (SOC) between the singlet and triplet excited states, and the SOC matrix element is up to 2 cm(-1) for compound showing the highest ISC efficiency. Femtosecond transient absorption spectra show the ISC rate constant of 8 x 10(9) s(-1) for MT-PBI, and no charge transfer exists. Photo-driven electron transfer was observed with the PBI derivatives in the presence of sacrificial electron donor triethanolamine (TEOA), and reversible formation of PBI radical anion (PBI-.) was observed, which shows absorption in the range of 600 nm-800 nm and 900 nm-1000 nm. Delayed fluorescence (P-type) in MT-PBI was also observed (tau(T) = 31.0 mu s). These finding are useful for the design of PBI-derived heavy atom-free compounds to be used as triplet photosensitizers.