Micromachines
·
2022
·Vol. 13
·期 11
·1857
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IF 3.523
Shisong Yu,Kai Zhang,Xiangcheng Cai,Peng Tu,Yuanming Zhou,Fei Mei
Organic-inorganic perovskite materials are widely used in the preparation of light-emitting diodes due to their low raw material cost, solution preparation, high color purity, high fluorescence quantum yield, continuously tunable spectrum, and excellent charge transport properties. It has become a research hotspot in the field of optoelectronics today. At present, the nonradiative recombination and fluorescence quenching occurring at the interface between the device transport layer and the light-emitting layer are still important factors limiting the performance of perovskite light-emitting diodes (PeLEDs). In this work, based on CH3NH3PbBr3perovskite, the effects of parameters such as precursor solution, anti-solvent chlorobenzene (CB), and small amine molecule phenylmethylamine (PMA) on the performance of perovskite films and devices were investigated. The research results show that adding an appropriate amount of PMA can reduce the grain size of perovskite, improve the coverage of the film, enhance the crystallinity of the film, and increase the fluorescence intensity of the perovskite film. When the PMA content is 0.050 vol.%, the maximum luminance of PeLEDs is 2098 cd/m2and the maximum current efficiency is 1.592 cd/A, which is greatly improved by 30% and 64.8% compared with the reference device without PMA doping. These results suggest that an appropriate amount of PMA can effectively passivate the defects in perovskite films, and inhibit the non-radiative recombination caused by the traps, thereby improving the optoelectronic performance of the device.Keywords:perovskite;phenylmethylamine;chlorobenzene;light-emitting diode
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Nature Communications
·
2022
·Vol. 13
·期 1
·1-9
·
IF 17.694
Wang Yunhu,Wang Kunpeng,Dai Fangxu,Zhang Kai,Tang Haifeng,Wang Lei,Xing Jun
Artificial lighting consumes almost one-fifth of global electricity. As an efficient solid-state lighting technology, white light-emitting diodes (WLEDs) have received increasing attention. However, the white luminescence of the traditional WLEDs comes from multi-component emitters, which leads to complex device structure and unstable emitting color. Therefore, developing single-component materials with white-light electroluminescence is of significance for artificial lighting applications. Here, we fabricate single-component white-light electroluminescence devices based on an aromatic carbon nitride material and improve the performance of WLEDs by adjusting the carrier transport. The carbon nitride LEDs emit warm-white light, of which color coordinates and color temperature are (0.44, 0.52) and 3700 K. The optimized LEDs display a very low turn-on voltage of 3.2 V and achieve a milestone in the maximum luminance and external quantum efficiency of 1885 cd m −2 and 1.20%. Our findings demonstrate the low-cost carbon nitride materials have promising potential for single-component WLEDs application.
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CHEMICAL ENGINEERING JOURNAL
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2022
·
IF 16.744
Shibo Wang,Fengxian Cao,Pengxu Chen,Ruowei He,Anling Tong,Zhang Lan,Peng Gao,Weihai Sun,Jihuai Wu
Combined with the superb moisture and thermal stability of two-dimensional (2D) perovskites and the excellent photoelectronic features of three-dimensional (3D) perovskites, building 3D/2D structure has been proved to be an auspicious way to improve both power conversion efficiency (PCE) and durability of perovskite solar cells (PSCs). In this work, cyclohexylammonium bromide (CMABr) as p-dopant is introduced into hole transport layer (HTL) to form 3D/2D heterostructure perovskite bilayer. It is confirmed that the formation of 2D perovskite interlayer comes from the reaction between the excess PbI 2 on the surface of 3D perovskite and CMABr on the bottom of HTL, which served as moisture barrier layer to enhance the device stability. The exotic CMA + and Br − ions could insert the ABX 3 perovskite lattice to compensate A-site cation and X-site vacancies, which reduced the undesirable non-radiative recombination centers. Owing to the p-type doping, the more uniform morphology, down-shifted energy levels and improved electrical properties were obtained. Consequently, the CMABr-doped PSCs based on triple-cation (Cs + , MA + and FA + ) perovskite and double-cation (MA + and FA + ) perovskite produce maximum PCEs of 21.78 % and 23.56 %, respectively, as well as remarkable long-term device stability. The results demonstrate a novel pathway to construct 3D/2D stacking structure for highly efficient PSCs with decent stability.
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Small
·
2022
·Vol. 18
·期 46
·2204742
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IF 15.153
Zihui Liang,Bowen Jin,Jinguo Cao,Fengxiang Chen,Jing Li,Shimin Wang,Kai Wang,Congcong Wu
Surface states are one of the crucial factors determining the phase stability of formamidinium-based perovskites. Compared with other compositions, exclusive lattice strain in FAPbI 3 perovskite generates defects at the surface more readily, making them more vulnerable at the surface and easier to trigger the phase transition from α-phase to the non-perovskite δ-phase. In order to regulate the surface quality, here, a chemi-mechanical cleavage approach is reported, i.e., tape peel-zone (PZ), implemented by attaching and peeling off the ordinary Kapton Tapes. The PZ approach can simultaneously eliminate the surface defects of perovskite and siliconize the film surface with hydrophobic silicone compounds. These two functionalities endow α-FAPbI 3 perovskite with a robust hydrophobic surface, which can sustain for 30 days under a relative humidity of 60% and withstand the high temperature up to 240 °C. The unencapsulated PZ-treated cells show 80.3% of initial performance after 90 h of continuous operation in ambient air, which is 31.4 times more stable than the pristine cell.
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Nano Materials Science
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2022
·
IF 0
Yi Yu,Zewei Liu,Xiaofei Chen,Shujun Liu,Chongxiong Duan,Hongxia Xi
The combination of nano sizes, large pore sizes and green synthesis is recognized as one of the most crucial and challenging problems in constructing metal-organic frameworks (MOFs). Herein, a water-based strategy is proposed for the synthesis of nanoscale hierarchical MOFs (NH-MOFs) with high crystallinity and excellent stability. This approach allows the morphology and porosity of MOFs to be fine tuned, thereby enabling the nanoscale crystal generation and a well-defined hierarchical system. The aqueous solution facilitates rapid nucleation kinetics, and the introduced modulator acts as a deprotonation agent to accelerate the deprotonation of the organic ligand as well as a structure-directing agent (SDA) to guide the formation of hierarchical networks. The as-synthesized NH-MOFs (NH-ZIF-67) were assessed as efficient adsorbents and heterogeneous catalysts to facilitate the diffusion of guest molecules, outperforming the parent microZIF-67. This study focuses on understanding the NH-MOF growth rules, which could allow tailor-designing NH-MOFs for various functions.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2022
·
IF 9.136
Yansu Lan,Die Zhou,Longhuan Lai,Huanhuan Qi,Lei Xia,Stef Depuydt,Bart Van der Bruggen,Yan Zhao
Bromide recovery from waste streams is crucial for both environmental and economic reasons. Membrane technology has shown great potential in achieving efficient ion separation, credited to the use of separation membranes with well-defined pore structure down to molecular level and surface charge properties. Herein, a class of novel anion exchange membranes (AEMs) was fabricated by brominated poly (2,6-dimethyl-1, 4-phenyl oxide) (BPPO) and different content of 4-hydroxy-1-methylpiperidine (HMP) via the chemical substitution reaction for Br - recovery. The resulting membrane (HMP@BPPO-0.1) had an ion exchange capacity of 1.69 mmol g −1 , a water content of 14.4 %, a swelling rate of 4.7 %, a surface electrical resistance of 3.68 Ω cm 2 and a limiting current density of 28.4 mA cm −2 . In addition, under a constant voltage of 15.0 V for 180 min in electrodialysis, the removal ratio of NaBr solution was 98.15 %, which was higher than that of the commercial AEM (ASE) (97.1 %) under the same testing conditions. To evaluate the Br - selectivity, the membranes were tested for an initial concentration of 50 mM of NaCl, NaBr and Na 2 SO 4 in a mixed solution with a constant current density of 2.5 mA cm −2 , 5.0 mA cm −2 and 10.0 mA cm −2 . The results showed that the permselectivity of the HMP@BPPO-0.1 for 100 min was as high as 12.6 (Br - /SO 4 2- ) and 1.20 (Br - /Cl - ) under the 5.0 mA cm −2 electric field, and the ion permeation rate of Cl - , Br - and SO 4 2- were 0.78, 1.20 and 0.20 mol −1 m -2 h −1 , respectively. Compared to the ASE membrane and the resulting membrane with negatively charged modification layer, this work suggests novel ideas in fabricating a membrane with Br - selectivity in view of resource recovery.
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Solar RRL
·
2022
·Vol. 6
·期 12
·2200737
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IF 9.173
Yupeng Zheng,Xueqing Xu,Shijun Liu,Gang Xu,Zhuoneng Bi,Yanqing Zhu,Kai Wang,Shengzhong (Frank) Liu,Antonio Guerrero,Guichuan Xing
Perfecting large-area perovskite film coating technology remains a key challenge to commercialize perovskite solar cells. Herein, nontoxic dimethyl sulfoxide (DMSO) is recommended as the only solvent to fabricate formamidinium (FA)–cesium lead halide perovskite by heat-assisted blade coating. DMSO effectively promotes the formation of α-phase crystals and improves the crystallinity. In addition, high substrate temperature is found to improve the film compactness, preferred facet orientation, and desired phase transition. Fast coating mode is adopted to inhibit ion migration and reduce the hysteresis of solar cells. Without any additives or surface treatments, the resulting perovskite film with chemical formula FA 0.75 Cs 0.25 PbI 2.7 Br 0.3 shows smooth surface, dense grains, and excellent crystallinity. The corresponding solar cells achieve efficiencies of 20.2% and 17.1% with active areas of 0.1 and 1.0 cm 2 , respectively. The unencapsulated devices maintain ≈100% and 70% of their initial efficiencies after 500 h of storage in air with relative humidity of about 25% and heating at 85 °C, respectively.
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Materials Today Physics
·
2022
·
IF 11.021
Siqi Sun,Pei Jia,Qizhang Huang,Min Lu,Po Lu,Feisong Qin,Guang Sun,Yanbo Gao,Xue Bai,Zhennan Wu,Yu Zhang
Despite rapid development of perovskite nanocrystal (PeNC) light-emitting diodes (LEDs), it remains challenging to achieve efficient and stable blue PeLEDs , especially for pure-blue PeLEDs required for displays. Mixed halide CsPb(Br/Cl) 3 NC is a common strategy to achieve pure-blue emission, but suffers from low photoluminescence quantum yield (PLQY) and spectra instability. Here, a facile approach for the synthesis of high-quality pure-blue emitting CsPb(Br/Cl) 3 NCs is reported by introducing an organic sulfonate, phenyl trifluoromethanesulfonate (PTFMS), which works as an efficient surface passivator. As a result, the optimized PeNCs achieve a high PLQY of 85% and enhanced conductivity. Furthermore, the LED based on the optimized PeNCs is developed with pure-blue emission at 469 nm, which yields an external quantum efficiency (EQE) of 1.20% and luminance of 355 cd m −2 . More impressively, the device shows excellent spectra and operation stability under voltage bias , resulting from the suppressed ion migration channels by efficient defect passivation .
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ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Fanghao Ye,Huibo Yan,Siyang Liu,Baoxing Liu,Zhiqing Zhang,Mengyao Tian,Ting Zheng,Xi Lan,Jincheng Huang,Chunfeng Meng,Ping Xu,Guijun Li
Perovskite light-emitting diodes (PeLEDs) have become a hot research topic in recent years and can now achieve an external quantum efficiency (EQE) of over 22% for green and red devices. However, the efficiency of blue PeLEDs, which are essential for display applications, lags far behind their green and red counterparts. The interface of the PeLEDs has a critical influence on the carrier transport and exciton recombination dynamics, and interface engineering is considered to be an effective strategy to improve the device performance. Herein, quaternary ammonium-based ionic liquids serve as an interfacial modification layer to significantly improve the device efficiency and stability. The interaction of quaternary ammonium cations with Pb(Br/Cl)6 octahedra promotes nucleation sites, which significantly improves the morphology of perovskite films and reduces the formation of defects in films. In addition, ion migration is also effectively suppressed in the device. As a result, with tributylmethylammonium bromide (TMAB) used as the interface layer, the EQE of the device is successfully increased from 3.5 to 6.7%, and the operational stability with a half-lifetime (T50) is increased by over 12 times. Our work provides a new class of interface modification materials toward high-performance blue PeLEDs.
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Energy Technology
·
2022
·Vol. 11
·期 1
·2200544
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IF 4.149
Guizhang Sheng,Yajie Zhao,Jieyuan Zheng,Lirong Chen,Baotian Qiu,Liuwen Zhong,Yanqing Zhu,Gang Xu,Xiudi Xiao
CsPbIBr 2 has shown great potential in the optoelectronics field due to its well-balanced relationship between bandgap and durability among all-inorganic perovskites materials. However, the CsPbIBr 2 thin films prepared by the traditional one-step spin coating method suffer from unsatisfactory morphology, poor crystallinity, and high defect density, which lead to the degradation of device performance. Herein, a simple preannealing method is used to form unstable transition films which are then annealed at high temperature to obtain CsPbIBr 2 perovskite films with uniform morphology, free pinholes, and strong crystallinity. The performance of the device can be effectively improved due to the reduction of defects and the optimization of the contact between functional layers. Therefore, the power conversion efficiency of 9.6% is obtained, which is nearly 100% improvement compared with that of the control device.
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Journal of Energy Chemistry
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2022
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IF 13.599
Qi Liu,Junming Qiu,Xianchang Yan,Yuemeng Fei,Yue Qiang,Qingyan Chang,Yi Wei,Xiaoliang Zhang,Wenming Tian,Shengye Jin,Ze Yu,Licheng Sun
All-inorganic CsPbIBr 2 perovskite solar cells (PSCs) have attracted considerable research attention in recent years due to their excellent thermal stability. However, their power conversion efficiencies (PCEs) are relatively low and still far below the theoretical limit. Here, we report the use of an organic dye molecule (namely VG1-C8) as a bifunctional interlayer between perovskite and the hole-transport layer in CsPbIBr 2 PSCs. Combined experimental and theoretical calculation results disclose that the multiple Lewis base sites in VG1-C8 can effectively passivate the trap states on the perovskite films. Meanwhile, the π-conjugated dye molecule significantly accelerates the hole extraction from the perovskite absorber as evidenced by the photoluminescence analysis. Consequently, the VG1-C8 treatment simultaneously boosts the photovoltage and photocurrent density values from 1.26 V and 10.80 mA cm −2 to 1.31 V and 12.44 mA cm −2 , respectively. This leads to a significant enhancement of PCE from 9.20% to 12.10% under one sun irradiation (AM 1.5G). To our knowledge, this is the record efficiency reported so far for CsPbIBr 2 PSCs. Thus, the present work demonstrates an effective interfacial passivation strategy for the development of highly efficient PSCs.
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ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Yalan Zhang,Tinghuan Yang,Raja sekhar Bobba,Abiral Baniya,Tianqi Niu,Sally Mabrouk,Shengzhong Liu,Quinn Qiao,Kui Zhao
The combination of organic ligands and inorganic Pb–I frameworks in layered perovskites has bestowed upon them high structural tunability and stability, while their microscopic degradation mechanism remains unclear. Here, we found the key role of ligands in intrinsic structural stability and the consequent morphological evolution in layered perovskites during long-term ambient aging based on (GA)(MA)nPbnI3n+1 (GA = guanidinium, = 4) and (BDA)(MA)n−1PbnI3n+1 (BDA = 1,4-butanediammonium, < n > = 4) perovskites. The BDA-based perovskites have a low intrinsic stability due to high crystal formation energy (ΔH), which are prone to hydration during ambient aging. We overserved changed crystal orientation from perpendicular to parallel, a delayed charge populating time from <1 ps to >50 ps, an inhibited carrier transfer kinetics between quantum wells, an increase of 0.9 μs of charge carrier transport time and a decrease of 1.2 μs of charge carrier lifetime in the BDA-based film during ambient aging, which accounts for a large power-conversion efficiency (PCE) loss (14.2% vs 11.2%). By contrast, the GA ligand increases the intrinsic structural stability of perovskites, which not only yields an initial PCE as high as 20.0% but also helps retain excellent optoelectronic properties during aging. Therefore, only a slight PCE loss (20.0% vs 19.1%) was observed. Our work reveals the key role of organic–inorganic interaction affecting the intrinsic structural stability and optoelectronic properties, and provides a theoretical basis for the future design of stable and efficient optoelectronic devices.
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