Enhanced Photocurrent of All-Inorganic Two-Dimensional Perovskite Cs₂PbI₂Cl₂ via Pressure-Regulated Excitonic Features

Abstract

Pressure processing is efficient to regulate the structural and physical properties of two-dimensional (2D) halide perovskites which have been emerging for advanced photovoltaic and light-emitting applications. Increasing numbers of studies have reported pressure-induced and/or enhanced emission properties in the 2D halide perovskites. However, no research has focused on their photoresponse properties under pressure tuning. It is also unclear how structural change affects their excitonic features, which govern the optoelectronic properties of the halide perovskites. Herein, we report significantly enhanced photocurrents in the all-inorganic 2D perovskite Cs2PbI2Cl2, achieving over 3 orders of magnitude increase at the industrially achievable level of 2 GPa in comparison with its initial photocurrent. Lattice compression effectively regulates the excitonic features of Cs2PbI2Cl2, reducing the exciton binding energy considerably from 133 meV at ambient conditions to 78 meV at 2.1 GPa. Impressively, such a reduced exciton binding energy of 2D Cs2PbI2Cl2 is comparable to the values of typical 3D perovskites (MAPbBr3 and MAPbI3), facilitating the dissociating of excitons into free carriers and enhancing the photocurrent. Further pressurization leads to a layer-sliding-induced phase transition and an anomalous negative linear compression, which has not been observed so far in other halide perovskites. Our findings reveal the dramatically enhanced photocurrents in the 2D halide perovskite by regulating its excitonic features and, more broadly, provide new insights into materials design toward extraordinary properties.

Enhanced Photoluminescence and Photoresponsiveness of Eu3+ Ions‐Doped CsPbCl3 Perovskite Quantum Dots under High Pressure

“…The light‐harvesting ability for solar energy conversion is a key parameter for photovoltaic materials. [ 46 ] To further explore the potential application of Eu 3+ ion‐doped CsPbCl 3 QDs in optoelectronic devices, we conducted in situ photocurrent measurements of the QDs under compression and compared the photoresponsiveness before and after high‐pressure treatment. The schematics of the sample chamber configuration and the optical image of the sample in a diamond anvil cell (DAC) is shown in Figure S8 in the Supporting Information.…”

Harvesting Cool Daylight in Hybrid Organic–Inorganic Halides Microtubules through the Reservation of Pressure‐Induced Emission

“…demonstrated that an optimal distortion in metal halide perovskites is preferred to determine the PIE. [ 26,28–30 ] In addition, Li et al. reported an irreversible phase transition of acetamidinium nitrate by introducing CH 3 to impart steric hindrance, thus increasing the potential barrier of phase transition to stabilize the high‐pressure phase.…”

Self-trapped exciton emission and piezochromism in conventional 3D lead bromide perovskite nanocrystals under high pressure

“…They are regarded as deal candidates for high-efficiency light-emitting diodes because of high quantum efficiency, high color purity, and easy tunability of wavelengths. [4][5][6][7][8] However, realization of white emission based on STEs in 3D perovskite materials is challenging.…”