Phosphorescence Through Hindered Motion of Pure Organic Emitters

Abstract

This minireview deals with the phenomenon of room-temperature phosphorescence induced by aggregation or crystallisation. Recent achievements, as well as novel classes of these unique luminophores, are put in to focus. In this fashion, different compounds, which reveal delayed fluorescence or phosphorescence upon fixation in a crystal lattice or within aggregates are described. Furthermore, the photophysical properties, the origin of the long-lived triplet states, and the possible applications of these fascinating classes of molecules are also discussed. To conclude, a short overview about the state of art in the field of pure organic phosphors at room temperature is presented.

Observation of Dual Room Temperature Fluorescence–Phosphorescence in Air, in the Crystal Form of a Thianthrene Derivative

“…reducing the non-radiative decay rate and removing or reducing the effects of quenching caused by oxygen. As it has been shown in previous works, 1,6,[11][12][13] the non-radiative decay rate can be suppressed when the compound is dispersed in a rigid solid matrix. This can be either a polymeric or small molecule host.…”

“…1,2 Spin-orbit coupling interactions induced by the nπ* transitions and the heavy-atom effect caused by the presence of sulfur, lead to its remarkable phosphorescent properties. [3][4][5][6][7] As a result, thianthrene and its analogs are mediocre photoluminescence emitters in conditions where the triplet state is effectively quenched by the surrounding environment, i.e. in solution or in the presence of oxygen.…”

Organic room-temperature phosphorescence from halogen-bonded organic frameworks: hidden electronic effects in rigidified chromophores

“…In recent decades, organic phosphorescence has become a more widely explored topic due to the discovery of long-lasting RTP by utilising crystallisation, [6][7][8] aggregation, 9,10 halogen bonding, [11][12][13][14] heavy atoms, 15 and carbonyl substituents [16][17][18] to circumvent the aforementioned issues. [19][20][21][22][23][24][25][26][27][28] Although spin-orbit coupling (SOC) in organic molecules is usually small (on the order of 1 cm À1 , cf. 10 2 to 10 3 cm À1 for organometallic complexes), the introduction of a carbonyl functionality to aromatic rings oen opens up a 1 (n-p*) / 3 (p-p*) (or 1 (p-p*) / 3 (n-p*)) channel with SOC $100 cm À1 .…”

Polymorphic Pure Organic Luminogens with Through‐Space Conjugation and Persistent Room‐Temperature Phosphorescence

“…Recently,p ure organic luminogens with room-temperature phosphorescence (RTP) [1][2][3][4] have attracted increasing attention owing to their fundamentali mportance in deciphering the photophysical processes of singleta nd triplet excitons, [5][6][7][8][9][10] as well as their potentiala pplications in sensing, [5,[11][12][13] bioimaging, [14][15][16] anticounterfeiting, [8,[17][18][19] and so forth. In particular, those with persistent RTP (p-RTP) are also promising owing to the retaining of RTP emissione ven after ceasing the excitation sources, which means they can be used in encryption, oxygen and chemical sensing, and high-resolution molecular imaging with ideal signal-to-noise ratios.…”