Reducing Nonradiative Losses of Air‐Processed Perovskite Films via Interface Modification for Bright and Efficient Light Emitting Diodes

Abstract

Developing ambient‐air fabrication strategy is desirable for lowering down the fabrication cost of perovskite light emitting diodes (LEDs) and further promoting their broad applications. However, ambient humidity usually leads to undesirable interface and perovskite film quality, causing severe nonradiative losses and unsatisfactory device performance. In this work, an effective strategy to solve this problem and remarkably enhance the performance of perovskite LEDs is reported. The study reveals that the humidity‐induced aggregation of self‐assembled monolayer (SAM) in humid air can be eliminated by introducing a poly[(9,9‐bis(3′‐((N,N‐dimethyl)‐N‐ethylammonium)‐ propyl)‐2,7‐fluorene)‐alt‐2,7‐(9,9‐dioctylfluorene)] dibromide (PFNBr) as an interface modifier, which reduces the interfacial defects and improves the perovskite crystallinity. The interaction between PFNBr and perovskite can further passivate the defects and suppress trap‐assisted nonradiative processes, which significantly enhances the photoluminescence efficiency of the ambient‐processed perovskite films. Furthermore, the energy level alignment is optimized and the hole injection is improved, thus resulting in more efficient and balanced charge injection. As a result, the green perovskite LEDs achieve a high external quantum efficiency of 12.06% and luminance of 22121 cd m−2, representing the record values for the perovskite LEDs processed under such ambient‐air condition, in accompany with an improved device stability.

Modification of Nickel Oxide via Self-Assembled Monolayer for Enhanced Performance of Air-Processed FAPbl3 Perovskite Solar Cells

“…In humid air, the Me-4PACz molecules tend to aggregate themselves to reduce the contact between the hydrophobic groups with the moisture, which might be aggravated at high concentrations. 35,36 The results presented above indicate the dramatic enhancement of photovoltaic performance via interfacial modification with Me-4PACz. To explore the underlying reason why Me-4PACz can improve the performance of the device, we To verify the existence of Me-4PACz at the NiO x film surface, we performed X-ray photoelectron spectroscopy (XPS), and the wide spectrum is given in Figure S4a.…”

“…However, the PCE of the device decreases slightly when increasing the concentration to 1.2 mg mL –1 , which might result from the aggregation of Me-4PACz. In humid air, the Me-4PACz molecules tend to aggregate themselves to reduce the contact between the hydrophobic groups with the moisture, which might be aggravated at high concentrations. , …”

Investigating the Thermal Conductance of the Cu/Si Interface Using the Molecular Dynamics Method

“…Step 2: Determining the nearest-neighbor relationships between the two sides of the interface structure, i.e., r(n) and b(n) in Equation (1). With this, the Mobius inversion is applied to obtain J(n) and B(n), as stated in Equation (2).…”

“…Thermal resistance is important for many new fields, such as light-emitting diodes [1,2], quantum cascade lasers [3,4], phase-change memory [5,6], thermoelectric devices [7,8], wearable devices [9], and photovoltaic cells [10,11]. Lastly, thermal dissipation in batteries plays a crucial role [12].…”

Phosphonic Chloride Assisted Fabrication of Highly Emissive Mixed Halide Perovskite Films in Ambient Air for Blue Light-Emitting Diodes

“…Later, Li et al replaced the hygroscopic hole transport layer (HTL) by a nonhygroscopic self-assembled monolayer (SAM) and fabricated the quasi-2D green CsPbBr 3 perovskite in air with a broader humidity window . The interface between the air-processed SAM and perovskite emitting layer was further optimized to reduce the nonradiative losses, thus significantly improving the performance of PeLEDs . As for blue PeLEDs, efforts have been made to suppress the degradation of perovskite films by ambient water to enable the air processability. , For example, Li et al engineered the HTL to reduce the effects of adsorbed moisture on the crystallization of perovskite, thus obtaining thin quasi-2D CsPbBr 3 perovskite and blue emission .…”