Enhanced Near‐Infrared Perovskite Light‐Emitting Devices by Introducing Choline Chloride Layer

Abstract

The existing interface defect states between perovskite and the transport layer is one of the dominant reasons to limit the performance of near‐infrared (NIR) perovskite light‐emitting devices (PeLEDs). Herein, a quaternary ammonium halide choline chloride layer is introduced to improve the wettability of the hole transport layer (HTL) and passivate defect states. As a consequence, the performance of the NIR PeLEDs is obviously enhanced. A maximum output power density of 4.7 mW cm−2 has been achieved by optimizing the concentration of choline chloride. Furthermore, the alternating current (AC) driving mode is introduced to reduce thermal degradation and charge accumulation in the interface region. It is demonstrated that the emission intensity as well as the stability of PeLEDs can be further improved.

High‐Efficiency Air‐Processed Si‐Based Perovskite Light‐Emitting Devices via PMMA‐TBAPF6 Co‐Doping

“…The choline chloride was spin‐coated onto the HTL at 4000 rpm for 60 s with annealing at 100 °C for 10 min to form a passivation layer. [ 8 ] The perovskite precursor was then deposited on choline chloride with two‐step spin‐coating procedures in air‐ambient. The first step was 500 rpm for 10 s with an acceleration rate of 200 rpm/s.…”

“…To enhance the Si-based PeLEDs, energy level control, band matching, as well as interface passivation between perovskite and silicon are still problems that need to be solved.In previous works, [6,7] we first fabricated Si-based PeLEDs and enhanced the EQE from less than 0.1% to 0.91% via energy level control. Then, we passivated the interface defects in the device [8] and adjusted the device structure to increase device efficiency. [9] Further, the surface of the perovskite was modified by PMMA anti-solvent doping, so that the device can operate normally in a high humidity atmosphere, and an EQE of 7.5% is obtained.…”

Optoelectronic devices based on the integration of halide perovskites with silicon-based materials

“…11g). 26 Choline chloride was used as passivation layer to improve the EL intensity of devices. The LEDs with 0.5 mg ml À1 choline chloride achieved higher EL intensity than other devices.…”

“…25 Furthermore, Xu et al used a similar design to fabricate Si-based MAPbI 3 LEDs with near-infrared (787 nm) emission. 26 Fig. 1d shows the schematic illustration of an optically pumped perovskite/Si laser as reported e.g.…”

Recent Progress in AC-Driven Organic and Perovskite Electroluminescent Devices

“…Nevertheless, AC-driven EL devices have obvious advantages in some important aspects, including stable operation and color tunable integrated devices. For example, Xu et al demonstrated the perovskite quantum dot LEDs in different drive modes (DC and AC) . The operating stability of AC-driven EL devices was 4× longer than that of DC-driven devices at a high current density of 300 mA cm –2 , which was ascribed to the suppressed heating and reduced charge accumulation during operation.…”