Light-Induced Charge Transfer in Two-Dimensional Hybrid Lead Halide Perovskites

Abstract

2D hybrid perovskites consisting of layers of lead halide octahedra separated by long organic linker cations have great potential for functional material design toward tailored optical and electronic properties. Here, we report the first direct observation of light-induced charge transfer (CT) in a series of novel 2D perovskites incorporating conjugated linkers based on the carbazole molecule. Dedicated electron paramagnetic resonance experiments and supporting quantum-chemical calculations reveal that excitons generated in the lead halide layer undergo CT at the organic–inorganic interface, resulting in a positive polaron delocalized over several carbazole moieties and a partner electron residing in the inorganic layer. The occurrence of such CT processes in these materials not only offers interesting new perspectives for the functionalization of future 2D perovskites but could also lead to a better understanding of the unusual broadband emission reported for this material class, which has been directly related to polaronic effects.

Quasi‐2D Hybrid Perovskite Formation Using Benzothieno[3,2‐b]Benzothiophene (BTBT) Ammonium Cations: Substantial Cesium Lead(II) Iodide Black Phase Stabilization

“…Although it has been shown that simple aliphatic or aromatic ammonium cations (e.g., BA or PEA) can be applied toward the stabilization of the cesium lead(II) iodide black phase through dimension engineering, the insertion of more complex organic ammonium cations, potentially bestowing additional optical properties [34][35][36] and charge carrier dynamics to the hybrid, [37][38][39][40][41][42] has not been applied for the same purpose. In addition, approaches to increase the phase purity of quasi-2D hybrid perovskite films have been poorly investigated to date.…”

Navigating the Site-Distinct Energy Conversion Properties of Perovskite Quantum Wells

“…Goovaerts’s group observed an inorganic-to-organic hole transfer in the 2D HPs constructed by a carbazole-contained spacer molecule due to a type-II band alignment between the HP skeleton and the spacer layer . Dou’s group experimentally demonstrated the modular design of the organic energetics in n = 1 2D HPs .…”

“…117,118 Goovaerts's group observed an inorganic-to-organic hole transfer in the 2D HPs constructed by a carbazole-contained spacer molecule due to a type-II band alignment between the HP skeleton and the spacer layer. 119 Dou's group experimentally demonstrated the modular design of the organic energetics in n = 1 2D HPs. 115 Bithiophene unit (2T), 4Tm, 4TCNm, and BTm were utilized, and the corresponding intralayer energy landscapes are shown in Figure 8a−d.…”

Recent Progress of Organic Semiconductor Materials in Spintronics

“…This work broadened the material system of the organic spin transport layer. Although the hybrid organic‐inorganic perovskites contain halogen and heavy elements, which have a particular impact on their spin transport performance, HOIPs still have potential applications drawn upon their excellent conductivity, [57] flexibility, and adjustable photoelectric performance [58] . Besides, there are also reports of high‐performance pure organic perovskites [59] recently.…”