Wei, Yi Samori, Shingo Tojo, Sachiko Fujitsuka, Mamoru Lin, Jin-Sheng Chen, Chien-Tien Majima, Tetsuro Emission Mechanism of Doubly <i>ortho</i>-Linked Quinoxaline/Diphenylfluorene or <i>cis</i>-Stilbene/Fluorene Hybrid Compounds Based on the Transient Absorption and Emission Measurements during Pulse Radiolysis A series of bipolar OLED materials were subjected to pulsed radiolysis experiments to determine their transient absorption and lifetime profiles of the independently in situ generated radical cations and anions in solutions. Moreover, their emission behaviors from the charge recombination of their radical ions were also determined by the pulse radiolysis method. It was found the absorption bands in doubly <i>ortho</i>-linked quinoxaline/diphenylfluorene hybrids <b>1a</b>−<b>e</b> are red-shifted progressively with increasing electron-donating nature at the C5 and C8 positions of the quinoxaline template. The incipient radical anions in <b>1a</b>−<b>e</b> are mainly localized on the quinoxaline heterocyclic moiety, whereas the incipient radical cations are mainly distributed onto the attached electron-donating groups at the C5 and C8 positions of the quinoxaline template. For other doubly <i>ortho</i>-linked <i>cis</i>-stilbene derivatives <b>3d</b>, <b>3f</b>, and <b>4f</b>, the radical anions are mainly localized on the <i>cis</i>-stilbene central moiety and the radical cation is mainly distributed onto both <i>para</i> substituents of the <i>cis</i>-stilbene templates. It was also shown that there is a correlation between their optoelectronic emission efficiencies and the radiolysis induced emission intensities. In addition, the charge transporting behaviors within an OLED device were found to show the relationship with transient absorption half-lives (τ<sub>1/2</sub>) of the radical ions. Charge recombination mechanisms in both the OLED and pulsed radiolysis experiments were proposed to rationalize these observations, allowing us to establish some guidelines for an ultimate molecular design of ideal bipolar optoelectronic materials with a judicious choice of local charge appendages in the optoelectronic templates. Emission;absorption;anion;quinoxaline template;C 8 positions;optoelectronic emission efficiencies;bipolar OLED materials;pulse radiolysis method;bipolar optoelectronic materials;Pulse RadiolysisA series;charge recombination mechanisms;C 5;cation;quinoxaline heterocyclic moiety;radiolysis experiments 2009-05-20
    https://acs.figshare.com/articles/journal_contribution/Emission_Mechanism_of_Doubly_i_ortho_i_Linked_Quinoxaline_Diphenylfluorene_or_i_cis_i_Stilbene_Fluorene_Hybrid_Compounds_Based_on_the_Transient_Absorption_and_Emission_Measurements_during_Pulse_Radiolysis/2855746
10.1021/ja8090005.s001