Edge stabilization in reduced-dimensional perovskites

Abstract

Reduced-dimensional perovskites are attractive light-emitting materials due to their efficient luminescence, color purity, tunable bandgap, and structural diversity. A major limitation in perovskite light-emitting diodes is their limited operational stability. Here we demonstrate that rapid photodegradation arises from edge-initiated photooxidation, wherein oxidative attack is powered by photogenerated and electrically-injected carriers that diffuse to the nanoplatelet edges and produce superoxide. We report an edge-stabilization strategy wherein phosphine oxides passivate unsaturated lead sites during perovskite crystallization. With this approach, we synthesize reduced-dimensional perovskites that exhibit 97 ± 3% photoluminescence quantum yields and stabilities that exceed 300 h upon continuous illumination in an air ambient. We achieve green-emitting devices with a peak external quantum efficiency (EQE) of 14% at 1000 cd m −2 ; their maximum luminance is 4.5 × 10 4 cd m −2 (corresponding to an EQE of 5%); and, at 4000 cd m −2 , they achieve an operational halflifetime of 3.5 h.

Molecular Intercalation and Electronic Two Dimensionality in Layered Hybrid Perovskites

“…For samples with n ≥2, the small A‐site cations CH 3 NH 3 + leads to the formation of 3D perovskite compositions at the edges. Therefore, for n ≥2, formation of 3D perovskite edge‐states gives lower energy emission with peak energy similar to that of a pure 3D perovskite . In our (BA) 2 PbI 4 ( n =1), neither smaller A‐site cations are present, nor the emission energy of edge states match with 3D perovskites.…”

Intermolecular π–π Conjugation Self‐Assembly to Stabilize Surface Passivation of Highly Efficient Perovskite Solar Cells

“…[ 11 ] PO electron‐donor group can hinder the production of superoxide by the attacking of oxygen better than NO, SO, PS, and PSe by pervious work. [ 12 ] Compared to the carboxyl and sulfinyl groups that have been widely used for the perovskite passivation, relatively larger difference in the electronegativity exists between P and O, which may help the oxygen atom of the PO to exhibit higher electron‐cloud density and thus stronger electron donating and coordination ability with the metal atoms, such as the Pb in the perovskite lattice. Here, triphenylphosphine oxide (TPPO) and tribenzylphosphine oxide (TBPO) with benzene rings and benzyls as side groups, respectively, are chosen for our experiment; their molecular structures are schematically shown in Figure a.…”

Chelating-agent-assisted control of CsPbBr3 quantum well growth enables stable blue perovskite emitters

“…The resulted clear and colorless solution was dripped onto the substrates after filtration, pre-spun at 1000 rpm for 10 s, then spin-coated at 5000 rpm for 60 s. After 25 s during the second step, 400 µL of chloroform dissolving TPPO (98%, Sigma-Aldrich) is deposited onto the perovskite film during the second step. Triphenylphosphine oxide (TPPO) is a passivating agent that has been reported in previous literature 26 . The second step is key to the crystal growth process as this step utilizes the antisolvent to form better film and control the perovskite growth 27 .…”