Distribution control enables efficient reduced-dimensional perovskite LEDs

Phosphonate/Phosphine Oxide Dyad Additive for Efficient Perovskite Light‐Emitting Diodes

“…Compared to the control film, the characteristic peaks of Pb (4f 7/2 at 143.102 eV and 4f 5/2 at 138.226 eV) and Br (3d 5/2 at 68.945 eV and 3d 3/2 at 68.000 eV) all shift to low binding energy after introducing these additives (Figure 2d), indicating the changed cationic charge and electrostatic interaction of Pb with Br in perovskite films. [19] Therefore, the interaction between PE-TPPO and perovskite can be confirmed.…”

“…[7][8][9][10][11] Among neutral additives, small molecules containing -NH 2 , CÀ OÀ C, C=O, P=O functional groups have been studied. [12][13][14][15][16][17][18][19] For example, amine-functionalized molecular additives were demonstrated to increase the defect passivation effect by reducing the hydrogen bonding between -NH 2 group and FA + (FA, formamidinium). [12] Recently, fluorinated triphenylphosphine oxide (TFPPO) with a P=O group chemically coordinating with unsaturated Pb was reported to suppress defects.…”

“…[12] Recently, fluorinated triphenylphosphine oxide (TFPPO) with a P=O group chemically coordinating with unsaturated Pb was reported to suppress defects. [19] In addition, the hydrogen bond between the F atom and PEA + (PEA, phenylethylammonium) can retard the formation of low-n domains and reduce the energy loss from insufficient energy transfer process.…”

“…The local enlarged absorption spectra (see the inserted image in Figure 3a) show that the formation of low n-domains is suppressed in all additive-modified films, indicating the interaction of the P=O@TPPO group with the perovskite component can influence the perovskite crystallization process. [19,24] Figure 3b shows the PL spectra with the intensity normalized by comparison with the control film. On introducing additives, the PL intensity is greatly enhanced, which should mainly result from the reduced energy loss related to low-n domains including defects and insufficient energy transfer.…”

Phosphonate/Phosphine Oxide Dyad Additive for Efficient Perovskite Light‐Emitting Diodes

“…Introduction of additives is an important strategy to improve the device efficiency of PeLEDs, and they can be divided into ionic and neutral ones [7–11] . Among neutral additives, small molecules containing ‐NH 2 , C−O−C, C=O, P=O functional groups have been studied [12–19] . For example, amine‐functionalized molecular additives were demonstrated to increase the defect passivation effect by reducing the hydrogen bonding between ‐NH 2 group and FA + (FA, formamidinium) [12] .…”