Abstract:Hybrid metal halide perovskite–based light‐emitting diodes and lasers have demonstrated outstanding performance and currently lead a new trend in the optoelectronic field; however, the widely used one‐step spin‐coating method assisted by an antisolvent suffers from the narrow processing window of antisolvents, which limits its further use in commercial applications. The present work incorporates trivalent‐neodymium ions (Nd3+) into methylammonium lead tribromide (MAPbBr3) perovskite thin films to control nucle… Show more
“…Meanwhile, the carrier densities are evaluated as 1.404 × 10 19 cm −3 for CsPbI 3 PQDs and 1.621 × 10 19 cm −3 for CsPbI 3 : Er 3+ (7.7%) PQDs. It is found that the effect reduces the trap density and increases the carrier densities of PQDs after Er 3+ doping, similar to the previous literatures 49 , 50 .…”
Broadband photodetection (PD) covering the deep ultraviolet to near-infrared (200–1000 nm) range is significant and desirable for various optoelectronic designs. Herein, we employ ultraviolet (UV) luminescent concentrators (LC), iodine-based perovskite quantum dots (PQDs), and organic bulk heterojunction (BHJ) as the UV, visible, and near-infrared (NIR) photosensitive layers, respectively, to construct a broadband heterojunction PD. Firstly, experimental and theoretical results reveal that optoelectronic properties and stability of CsPbI3 PQDs are significantly improved through Er3+ doping, owing to the reduced defect density, improved charge mobility, increased formation energy, tolerance factor, etc. The narrow bandgap of CsPbI3:Er3+ PQDs serves as a visible photosensitive layer of PD. Secondly, considering the matchable energy bandgap, the BHJ (BTP-4Cl: PBDB-TF) is selected as to NIR absorption layer to fabricate the hybrid structure with CsPbI3:Er3+ PQDs. Thirdly, UV LC converts the UV light (200–400 nm) to visible light (400–700 nm), which is further absorbed by CsPbI3:Er3+ PQDs. In contrast with other perovskites PDs and commercial Si PDs, our PD presents a relatively wide response range and high detectivity especially in UV and NIR regions (two orders of magnitude increase that of commercial Si PDs). Furthermore, the PD also demonstrates significantly enhanced air- and UV- stability, and the photocurrent of the device maintains 81.5% of the original one after 5000 cycles. This work highlights a new attempt for designing broadband PDs, which has application potential in optoelectronic devices.
“…Meanwhile, the carrier densities are evaluated as 1.404 × 10 19 cm −3 for CsPbI 3 PQDs and 1.621 × 10 19 cm −3 for CsPbI 3 : Er 3+ (7.7%) PQDs. It is found that the effect reduces the trap density and increases the carrier densities of PQDs after Er 3+ doping, similar to the previous literatures 49 , 50 .…”
Broadband photodetection (PD) covering the deep ultraviolet to near-infrared (200–1000 nm) range is significant and desirable for various optoelectronic designs. Herein, we employ ultraviolet (UV) luminescent concentrators (LC), iodine-based perovskite quantum dots (PQDs), and organic bulk heterojunction (BHJ) as the UV, visible, and near-infrared (NIR) photosensitive layers, respectively, to construct a broadband heterojunction PD. Firstly, experimental and theoretical results reveal that optoelectronic properties and stability of CsPbI3 PQDs are significantly improved through Er3+ doping, owing to the reduced defect density, improved charge mobility, increased formation energy, tolerance factor, etc. The narrow bandgap of CsPbI3:Er3+ PQDs serves as a visible photosensitive layer of PD. Secondly, considering the matchable energy bandgap, the BHJ (BTP-4Cl: PBDB-TF) is selected as to NIR absorption layer to fabricate the hybrid structure with CsPbI3:Er3+ PQDs. Thirdly, UV LC converts the UV light (200–400 nm) to visible light (400–700 nm), which is further absorbed by CsPbI3:Er3+ PQDs. In contrast with other perovskites PDs and commercial Si PDs, our PD presents a relatively wide response range and high detectivity especially in UV and NIR regions (two orders of magnitude increase that of commercial Si PDs). Furthermore, the PD also demonstrates significantly enhanced air- and UV- stability, and the photocurrent of the device maintains 81.5% of the original one after 5000 cycles. This work highlights a new attempt for designing broadband PDs, which has application potential in optoelectronic devices.
“…Many strategies have been implemented to maximize the PLQY of perovskites, such as defect passivation, metal ion doping, and crystal quality improvement by controlling crystal growth. [81][82][83][84] In addition, the different effects caused by k 1 and k 3 are primarily reflected in the high carrier density, corresponding to the high current density of LEDs. Figure 2d shows that at a high carrier density, the attenuation trend of PLQY is highly coincident and has a weak dependence on k 1 .…”
Metal halide perovskites have attracted considerable interest for their potential applications in high‐definition displays owing to their narrowband emission, wide color gamut (≈140%), near‐unity photoluminescence efficiency, and cost‐effective solution processability. Extensive efforts have led to the external quantum efficiency of state‐of‐the‐art perovskite light‐emitting diodes (PeLEDs) to exceed 20%. However, there are several obstacles, such as poor working stability, low efficiency, and low luminance, of pure‐blue and pure‐red light‐emitting devices that delay their commercial application. Addressing these issues requires a deep understanding of the photoluminescence effect as well as the bottlenecks in the process. Here, the fundamental working principle, carrier recombination, and light outcoupling properties of PeLEDs are described. The performance improvement strategies of PeLEDs based on defect engineering, perovskite crystallization, charge injection balancing, and quantum confinement are discussed. Furthermore, the challenges of PeLEDs in pure‐color light emission, working stability, and toxicity are reviewed and discussed.
“…These additives tend to interact with precursor solute in solution, promoting the heterogeneous nucleation of the perovskite, which help to extend the perovskite processing window. In the process of fabricating MAPbBr 3 film in dichloromethane, Zhang et al incorporated trivalent neodymium ions (Nd 3+ ) into perovskite thin precursor to control nucleation and crystal growth [105]. These pre-nucleated crystals in perovskite precursor make them less sensitive to rapid changes in the solvent environment during the high-speed rotation process, thus resulting in widening the processing window from 3-5 to 18 s (Figure 5(a)).…”
Section: Precursor Additivesmentioning
confidence: 99%
“…Therefore, the high reproducibility of high-quality perovskite films was attributable to 18C6 effectively suppressing the generation of 2H phase perovskites. Figure 5. (a) Schematic diagrams of the process of preparing MAPbBr 3 perovskite film via the antisolvent method and use of an Nd 3+ additive, and schematic diagrams of the nucleation process and crystal growth. Reprinted from [105] with permission. (b) Schematic diagram of the deposition process of perovskite films without and with 18C6.…”
Section: Precursor-solvent Engineering For Widening the Processing Wi...mentioning
Perovskite solar cells are promising candidates for next-generation photovoltaic devices with certified power-conversion efficiency for single-junction perovskite-based devices exceeded 25%. However, it remains challenging to fabricate a large-area and dense perovskite film using solution-based deposition methods. This is due to perovskite wet films being highly sensitive and unstable, and thus having only a narrow processing window. There is therefore a demand for ways to expand the processing window in the fabrication of perovskite films. Herein, we systematically review research on the role of precursor solutions and antisolvents during the perovskite formation process, and reveal the fundamental factors governing the width of the perovskite film-processing window. Then, we give an overview of current strategies for enlarging the processing window, which includes solvent and antisolvent engineering strategies. We conclude by summarizing current challenges in the development of perovskite solar modules with a wide processing window and provide perspectives for future development.
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