Space conjugation induced white light and room-temperature phosphorescence from simple organic small molecules: single-component WLED driven by both UV and blue chips

Abstract

Unique luminescence of non-conventional luminophores derived from space conjugation (SC) has recently attracted extensive interest. However, it is difficult to achieve highly efficient emission (especially white light one) from SC,...

Aggregation‐Induced Emission Leading to White Light Emission in Diphenylbenzofulvene Derivatives

“…[16] Strategies to achieve a single WLE molecule make use of dual band emission, [17] with either charge transfer and energy transfer systems, or luminogens that present both fluorescence and phosphorescence or even thermally activated delayed fluorescence (TADF) at room temperature. [11] These materials often have complex donor-acceptor structures, and they are synthesized through several steps and from expensive raw materials. On the other hand, many multicomponent systems possess intra-or intermolecular energy transfer (ET), which makes the process of color-mixing theory a challenge.…”

“…Therefore, researchers may develop a single white emissive molecule, [11,15] or combine molecules with different emissive wavelengths in a single mixture [16] . Strategies to achieve a single WLE molecule make use of dual band emission, [17] with either charge transfer and energy transfer systems, or luminogens that present both fluorescence and phosphorescence or even thermally activated delayed fluorescence (TADF) at room temperature [11] . These materials often have complex donor‐acceptor structures, and they are synthesized through several steps and from expensive raw materials.…”

“…According to Kasha's rule, photons can only be emitted from the lowest singlet or triplet excited states and since white light emission (WLE) covers 400–800 nm, it is very difficult to obtain WLE from a single molecule [11] . The standard colorimetric system, set up by the Commission Internationale de L'Eclairage (CIE) in 1931, [12] correlates two coordinates (x, y) to all colors with the ideal white light emission corresponding to the energy point with CIE coordinates of (0.33, 0.33) [13] .…”

“…[10] According to Kasha's rule, photons can only be emitted from the lowest singlet or triplet excited states and since white light emission (WLE) covers 400-800 nm, it is very difficult to obtain WLE from a single molecule. [11] The standard colorimetric system, set up by the Commission Internationale de L'Eclairage (CIE) in 1931, [12] correlates two coordinates (x, y) to all colors with the ideal white light emission corresponding to the energy point with CIE coordinates of (0.33, 0.33). [13] To obtain WLE, one can mix the three primary colors (red, green and blue, RGB) in a given proportion, or two complementary lights (orange or yellow with blue) as long as the connection line of their coordinates lies across the white light region.…”

“…To obtain WLE, one can mix the three primary colors (red, green and blue, RGB) in a given proportion, or two complementary lights (orange or yellow with blue) as long as the connection line of their coordinates lies across the white light region [14] . Therefore, researchers may develop a single white emissive molecule, [11,15] or combine molecules with different emissive wavelengths in a single mixture [16] . Strategies to achieve a single WLE molecule make use of dual band emission, [17] with either charge transfer and energy transfer systems, or luminogens that present both fluorescence and phosphorescence or even thermally activated delayed fluorescence (TADF) at room temperature [11] .…”