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1.
Hong‐Hua Fang Feng Wang Sampson Adjokatse Ni Zhao Maria Antonietta Loi 《Advanced functional materials》2016,26(26):4653-4659
Formamidinium lead iodide (FAPbI3) has a broader absorption spectrum and better thermal stability than the most famous methylammonium lead iodide, thus exhibiting great potential for photovoltaic applications. In this report, the light‐induced photoluminescence (PL) evolution in FAPbI3 thin films is investigated. The PL intensity evolution is found to be strongly dependent on the atmosphere surrounding the samples. When the film is exposed to air, its photoluminescence intensity is enhanced more than 140 times after continuous ultraviolet laser illumination for 2 h, and the average lifetime is prolonged from 17 to 389 ns. The enhanced photoluminescence implies that the trap density is significantly reduced. The comparative study of the photoluminescence properties in air, nitrogen, and oxygen/helium environment suggests that moisture is important for the PL enhancement. This is explained in terms of moisture‐assisted light‐healing effect in FAPbI3 thin films. With this study, a new method is demonstrated to increase and control the quality of hybrid perovskite thin films. 相似文献
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Sooeun Shin Pronoy Nandi Seongrok Seo Hyun Suk Jung Nam-Gyu Park Hyunjung Shin 《Advanced functional materials》2023,33(40):2301213
Excess lead(II) iodide (PbI2) has controversial roles in affecting the efficiency of perovskite solar cells (PSCs). Since the photoinstability of PbI2 is now known to largely accelerate perovskite degradation, suppressing and/or eliminating excess PbI2 is key to improving the stability of PSCs. Herein, process-dependent PbI2 formation on the surfaces of formamidinium lead triiodide (FAPbI3) films is examined. Due to the faster evaporation rate of organic substances, crystalline PbI2 as an inclusion is found within the triple junction grain boundaries. With this hypothesis, two strategies are suggested: control of the 1) vapor pressure and 2) stoichiometry of precursor solutions to induce sufficient reaction of FAPbI3. Although both strategies successfully eliminate the PbI2 as inclusions, due to the slower evaporation rate, vapor pressure control films also exhibit a larger grain size (≈1.18 µm) with a good film quality to attain the highest power conversion efficiency (PCE) of 24.5%. Furthermore, the phase stability of α-FAPbI3 is improved due to the elimination of the degradation sites induced by the photoinstability of PbI2. The findings explore the formation process of unwanted PbI2 (≈2.8%) and provide a simple method to effectively suppress its formation. This may further boost the PCE and stability, especially for FA-based perovskites. 相似文献
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Minhuan Wang Shaun Tan Yepin Zhao Pengchen Zhu Yanfeng Yin Yulin Feng Tianyi Huang Jingjing Xue Rui Wang Gill Sang Han Hyun Suk Jung Jiming Bian Jin-Wook Lee Yang Yang 《Advanced functional materials》2021,31(7):2007520
The vast majority of high-performance perovskite solar cells (PSCs) are based on multi-cation mixed-anion compositions incorporating methylammonium (MA) and bromide (Br). Nevertheless, the thermal instability of MA and the tendency of mixed halide compositions to phase segregate limit the long-term stability of PSCs. However, reports of MA-free and/or Br-free compositions are rare in the community since their performance is generally inferior. Here, a strategy is presented to achieve highly efficient and stable PSCs that are altogether cesium (Cs)-free, MA-free and Br-free. An antisolvent quenching process is used to in-situ deposit a polymeric interlayer to promote the growth of phase-pure formamidinium lead tri-iodide perovskite crystals with reduced defect density and to assist in photo-excited charge extraction. The PSCs developed are among the best-performing reported for such compositions. Moreover, the PSCs show superior stability under continuous exposure to both illumination and 85 °C heat. 相似文献
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Duong Nguyen Minh Lan Anh Thi Nguyen Cong Tai Trinh Changjun Oh Sangwon Eom Thanh Van Vu Jinwoo Choi Jae Hyun Sim Kwang-Geol Lee Jaeyong Kim Seong Chan Cho Sang Uck Lee Věra Cimrová Youngjong Kang 《Advanced functional materials》2021,31(17):2011093
Synthesis of 2D perovskites often demands long and bulky organic spacer cations, but they hamper optoelectronic properties of the resulting 2D perovskites. Novel low-dimensional single-cation perovskites with a general formula of FAm+2PbmBr3m+2 are prepared by using a quenching-assisted solution process, which leads to the wide dimensional control over 1D FA3PbBr5 (m = 1), 2D FAm+2PbmBr3m+2 (m ≥ 2), and 3D FAPbX3 (m = ∞) perovskites simply by changing the composition of precursors. In this case, formamidinium (FA) acts as both an A-site cation and spacer cation in FAm+2PbmBr3m+2. Unlike conventional 2D perovskites, FAm+2PbmBr3m+2 perovskites have (110) orientation. PVDF (poly(vinylidene fluoride)) preferentially stabilizes the low-dimensional FAm+2PbmBr3m+2 phases, which is utilized to fabricate the stable FAm+2PbmBr3m+2-PVDF composite films. The phase transitions from 1D and 2D to 3D are investigated in response to various stimuli, including humidity, ultraviolet, oxygen, and solvents, are exploited for rewritable phase-change memory films. 相似文献
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Wenbin Wang Dewei Zhao Fujun Zhang Ludong Li Mingde Du Changlei Wang Yue Yu Qianqian Huang Miao Zhang Lingliang Li Jianli Miao Zheng Lou Guozhen Shen Ying Fang Yanfa Yan 《Advanced functional materials》2017,27(42)
It is a great challenge to obtain broadband response perovskite photodetectors (PPDs) due to the relatively large bandgaps of the most used methylammonium lead halide perovskites. The response range of the reported PPDs is limited in the ultraviolet–visible range. Here, highly sensitive PPDs are successfully fabricated with low bandgap (≈1.25 eV) (FASnI3)0.6(MAPbI3)0.4 perovskite as active layers, exhibiting a broadband response from 300 to 1000 nm. The performance of the PPDs can be optimized by adjusting the thicknesses of the perovskite and C60 layers. The optimized PPDs with 1000 nm thick perovskite layer and 70 nm thick C60 layer exhibit an almost flat external quantum efficiency (EQE) spectrum from 350 to 900 nm with EQE larger than 65% under ?0.2 V bias. Meanwhile, the optimized PPDs also exhibit suppressed dark current of 3.9 nA, high responsivity (R ) of over 0.4 A W?1, high specific detectivity (D* ) of over 1012 Jones in the near‐infrared region under ?0.2 V. Such highly sensitive broadband response PPDs, which can work well as self‐powered conditions, offer great potential applications in multicolor light detection. 相似文献
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Solution-processed hybrid organic–inorganic perovskite light-emitting transistors (PeLETs) suffer from low brightness and environmental instability induced by temperature-activated trapping, ionic motion, and polarization effects, which so far have been hindering the realization of devices operating at room temperature. Here high quality thermally co-evaporated methylammonium lead iodide perovskite films are employed to minimize ionic motion and significantly improve the electroluminescence characteristics of the perovskite active layer, enabling stable device operation up to ≈ 310 K. The demonstration of PeLETs operating at and beyond room-temperature paves the way for practical applications in the rapidly evolving area of solid-state lighting, active-matrix displays, and visible light communications. 相似文献
9.
《Advanced Electronic Materials》2018,4(9)
Organic–inorganic halide perovskite is regarded as one of the potential candidates for next generation resistive switching memory (memristor) material because of fast, millivolt‐scale switching, multilevel capability, and high On/Off ratio. Here, resistive switching property of HC(NH2)2PbI3 (FAPbI3) depending on structural phase is reported. It is found that 1D hexagonal FAPbI3 (δ‐FAPbI3), formed at relatively low temperature, is active in memristor, while 3D trigonal FAPbI3 (α‐FAPbI3), formed at temperature higher than 150 °C, is inactive. Failure of switching from low resistance state to high resistance state is found for α‐FAPbI3, while δ‐FAPbI3 shows stable switching behavior. Density functional calculation reveals that iodine cluster in isotropic 3D α‐FAPbI3 is so stable after forming filament that the filament is hard to be ruptured at off state. However, for anisotropic δ‐FAPbI3, iodine cluster is not stable and migration barrier is much lower for c‐axis (0.48 eV) than for ab ‐plane (0.9 eV), which is beneficial for switching. The memristor devices based on δ‐FAPbI3 demonstrate endurance up to 1200 cycles with On/Off ratio (>105), retention time up to 3000 s, multilevel storage capacity, and working even at 80 °C. 相似文献
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Formamidinium lead triiodide (FAPbI3)‐based perovskite materials are of interest for photovoltaics in view of their close‐to‐ideal bandgap, allowing absorption of photons over a broad solar spectrum. However, FAPbI3‐based materials suffer from a notorious phase transition from the photoactive black phase (α‐FAPbI3) to nonperovskite yellow phase (δ‐FAPbI3) under ambient conditions. This transition dramatically reduces light absorbtion, thus, degrading the photovoltaic performance and stability of ensuring solar cells. In this study, 1‐hexyl‐3‐methylimidazolium iodide (HMII) ionic liquid (IL) is employed as an additive for the first time in FAPbI3 perovskite to overcome the above‐mentioned issues. HMII incorporation facilitates the grain coarsening of FAPbI3 crystal owing to its high‐polarity and high‐boiling point, which yields liquid domains between neighboring grains to reduce the activation energy of the grain‐boundary migration. As a result, the FAPbI3 active layer exhibits micron‐sized grains with substantially suppressed parasitic traps with an Urbach energy reduced by 2 meV. Hence, the resulting perovskite solar cell achieves an efficiency of 20.6% with notable increase in open circuit voltage (VOC) of 80 mV compared with HMII‐free cells (17.1%). More importantly, the HMII‐doped FAPbI3‐based cells show a striking enhancement in shelf‐stability under high humidity and thermal stress, retaining >80% of their initial efficiencies at 60 ± 10% relative humidity and ≈95% at 65 °C. 相似文献
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Shuaipeng Ge Xinwei Guan Yutao Wang Chun‐Ho Lin Yimin Cui Yunxia Huang Xinran Zhang Ruoxuan Zhang Xiaoting Yang Tom Wu 《Advanced functional materials》2020,30(25)
3D organic–inorganic and all‐inorganic lead halide perovskites have been intensively pursued for resistive switching memories in recent years. Unfortunately, instability and lead toxicity are two foremost challenges for their large‐scale commercial applications. Dimensional reduction and composition engineering are effective means to overcome these challenges. Herein, low‐dimensional inorganic lead‐free Cs3Bi2I9 and CsBi3I10 perovskite‐like films are exploited for resistive switching memory applications. Both devices demonstrate stable switching with ultrahigh on/off ratios (≈106), ultralow operation voltages (as low as 0.12 V), and self‐compliance characteristics. 0D Cs3Bi2I9‐based device shows better retention time and larger reset voltage than the 2D CsBi3I10‐based device. Multilevel resistive switching behavior is also observed by modulating the current compliance, contributing to the device tunability. The resistive switching mechanism is hinged on the formation and rupture of conductive filaments of halide vacancies in the perovskite films, which is correlated with the formation of AgIx layers at the electrode/perovskite interface. This study enriches the library of switching materials with all‐inorganic lead‐free halide perovskites and offers new insights on tuning the operation of solution‐processed memory devices. 相似文献
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Neha Arora M. Ibrahim Dar Mahmoud Hezam Wolfgang Tress Gwénolé Jacopin Thomas Moehl Peng Gao Abdulah Saleh Aldwayyan Benoit Deveaud Michael Grätzel Mohammad Khaja Nazeeruddin 《Advanced functional materials》2016,26(17):2846-2854
This study demonstrates the formation of extremely smooth and uniform formamidinium lead bromide (CH(NH2)2PbBr3 = FAPbBr3) films using an optimum mixture of dimethyl sulfoxide and N,N‐dimethylformamide solvents. Surface morphology and phase purity of the FAPbBr3 films are thoroughly examined by field emission scanning electron microscopy and powder X‐ray diffraction, respectively. To unravel the photophysical properties of these films, systematic investigation based on time‐integrated and time‐dependent photoluminescence studies are carried out which, respectively, bring out relatively lower nonradiative recombination rates and long lasting photogenerated charge carriers in FAPbBr3 perovskite films. The devices based on FTO/TiO2/FAPbBr3/spiro‐OMeTAD/Au show highly reproducible open‐circuit voltage (Voc) of 1.42 V, a record for FAPbBr3‐based perovskite solar cells. Voc as a function of illumination intensity indicates that the contacts are very selective and higher Voc values are expected to be achieved when the quality of the FAPbBr3 film is further improved. Overall, the devices based on these films reveal appreciable power conversion efficiency of 7% under standard illumination conditions with negligible hysteresis. Finally, the amplified spontaneous emission (ASE) behavior explored in a cavity‐free configuration for FAPbBr3 perovskite films shows a sharp ASE threshold at a fluence of 190 μJ cm?2 with high quantum efficiency further confirming the high quality of the films. 相似文献
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The lead halide-based perovskites, for instance, CH3NH3PbX3 and CsPbX3 (X=Cl, Br, I), have received a lot of attention. Compared with bulk materials, low-dimensional perovskites have demonstrated a range of unique optical, electrical and mechanical properties, which enable wide applications in solar cells, lasers and other optoelectronic devices. In this paper, we provide a summary of the research progress of the low-dimensional perovskites in recent years, from synthesis methods, basic properties to their optoelectronic applications. 相似文献
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Weiyin Gao Changshun Chen Chenxin Ran Hao Zheng He Dong Yingdong Xia Yonghua Chen Wei Huang 《Advanced functional materials》2020,30(34)
Pb‐based metal halide perovskites (MHPs) have emerged as efficient light absorbers in third‐generation photovoltaic devices, and the latest certified power conversion efficiency (PCE) of Pb‐based perovskite solar cells (PSCs) has reached 25.2%. Despite great progress, Pb‐based MHPs are affected by toxicity, which hinders their market entry in a potential future large‐scale commercialization effort. Therefore, the exploration of Pb‐free MHPs has become one of the alternative solutions sought in the community. Among all the Pb‐free MHPs, Sn‐based MHPs show great promise owing to their similar or even superior theoretical optoelectronic characteristics. After several years of development, the PCE of Sn‐based PSCs has recently been approaching 10%, with the breakthroughs mainly coming from A‐site cation engineering of Sn‐based MHPs. In this review, the crucial status of A‐site cation engineering strategies in the research of Sn‐based PSCs is highlighted. First, the way the features of A‐site cation influence the structure and characteristics of MHPs is systematically demonstrated. Then, the state‐of‐the‐art developments, focusing on A‐site cation engineering of Sn‐based MHPs, are comprehensively reviewed. Subsequently, the current challenges and opportunities for further boosting the performance of Sn‐based PSCs are discussed. Finally, conclusions and perspectives on the promising Sn‐based optoelectronic devices are discussed. 相似文献
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Lead halide perovskite (LHP) is a promising material for various optoelectronic applications. Surface coating on particles is a common strategy to improve their functionality and environmental stability, but LHP is not amenable to most coating chemistries because of its intrinsic weakness against polar solvents. Here, a novel method of synthesizing LHP microlasers in a super-saturated polar solvent using sonochemistry and applying various functional coatings on individual microlasers in situ is described. Cesium lead bromine perovskite (CsPbBr3) microcrystals, capped with organic poly-norepinephrine (pNE) layers, are synthesized. The catechol group of pNE coordinates to bromine-deficient lead atoms, forming a defect-passivating and diffusion-blocking shell. The pNE layer enhances the material lifetime of CsPbBr3 in water by 2000-fold, enabling bright luminescence and lasing from single microcrystals in water. Furthermore, the pNE shell permits biofunctionalization with proteins, small molecules, and lipid bilayers. Luminescence from CsPbBr3 microcrystals is sustained in water over 1 h and observed in live cells. The functionalization method may enable new applications of LHP laser particles in water-rich environments. 相似文献
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Tushar Gupta Debjit Ghoshal Anthony Yoshimura Swastik Basu Philippe K. Chow Aniruddha S. Lakhnot Juhi Pandey Jeffrey M. Warrender Harry Efstathiadis Ajay Soni Eric Osei‐Agyemang Ganesh Balasubramanian Shengbai Zhang Su‐Fei Shi Toh‐Ming Lu Vincent Meunier Nikhil Koratkar 《Advanced functional materials》2020,30(23)
Organic–inorganic halide perovskites are intrinsically unstable when exposed to moisture and/or light. Additionally, the presence of lead in many perovskites raises toxicity concerns. Herein, a thin film of barium zirconium sulfide (BaZrS3), a lead‐free chalcogenide perovskite, is reported. Photoluminescence and X‐ray diffraction measurements show that BaZrS3 is far more stable than methylammonium lead iodide (MAPbI3) in moist environments. Moisture‐ and light‐induced degradations in BaZrS3 and MAPbI3 are compared by using simulations and calculations based on density functional theory. The simulations reveal drastically slower degradation in BaZrS3 due to two factors—weak interaction with water and very low rates of ion migration. BaZrS3 photodetecting devices with photoresponsivity of ≈46.5 mA W?1 are also reported. The devices retain ≈60% of their initial photoresponse after 4 weeks under ambient conditions. Similar MAPbI3 devices degrade rapidly and show a ≈95% decrease in photoresponsivity in just 4 days. The findings establish the superior stability of BaZrS3 and strengthen the case for its use in optoelectronics. New possibilities for thermoelectric energy conversion using these materials are also demonstrated. 相似文献
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Bolun Li Xi Huang Xiang Wu Qiong Zuo Yunhao Cao Qi Zhu Yaohui Li Yuanhuan Xu Guanhaojie Zheng Dongcheng Chen Xu-Hui Zhu Fei Huang Hongyu Zhen Lintao Hou Jian Qing Wanzhu Cai 《Advanced functional materials》2023,33(28):2300216
Quasi-two-dimensional (Q-2D) perovskites are emerging as one of the most promising materials for photodetectors. However, a significant challenge to Q-2D perovskites for photodetection is their insufficient charge transport ability, which is mainly attributed to their hybrid low-dimensional n-phase structure. This study demonstrates that evenly-distributed 3D-like phases with vertical orientation throughout the film can greatly facilitate charge transport and suppress charge recombination, outperforming the prevalent phase structure with a vertical dimension gradient. Based on such a phase structure, a Q-2D Ruddlesden−Popper perovskite self-powered photodetector achieving a combination of exceptional figures-of-merit is realized, including a responsivity of 0.45 AW−1, a peak specific detectivity of 2.3 × 1013 Jones, a 156 dB linear dynamic range, and a rise/fall time of 2.89 µs/1.93 µs. The desired phase structure is obtained by utilizing a double-hole transport layer (HTL), combining hydrophobic PTAA and hydrophilic PEDOT: PSS. Besides, the dependence of the hybrid low-dimensional phase structure is also identified on the surface energy of the buried HTL substrate. This study gives insight into the correlation between Q-2D perovskites’ phase structure and performance, providing a valuable design guide for Q-2D perovskite-based photodetectors. 相似文献
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Ying‐Chiao Wang Junwei Chang Liping Zhu Xiaodong Li Changjian Song Junfeng Fang 《Advanced functional materials》2018,28(9)
Crystal engineering of CH3NH3PbI3 perovskite materials through template‐directed nucleation and growth on PbI2 nuclei dispersed in a polar fullerene (C60 pyrrolidine tris‐acid, CPTA) electron transport layer (ETL) (CPTA:PbI2) is proposed as a route for controlling crystallization kinetics and grain sizes. Chemical analysis of the CPTA:PbI2 template confirms that CPTA carboxylic acid groups can form a monodentate or bidentate chelate with Pb(II), resulting in a lower nucleation barrier that promotes rapid formation of the tetragonal perovskite phase. Moreover, it is demonstrated that a uniform CH3NH3PbI3 film with highly crystalline and large domain sizes can be realized by increasing the spacing between nuclei to retard perovskite crystal growth via careful control of the preferred nucleation site distribution in the CPTA:PbI2 layer. The improved perovskite morphology possesses a long photoluminescence lifetime and efficient photocarrier transport/separation properties to eliminate the hysteresis effect. The corresponding planar heterojunction photovoltaic yields a high power conversion efficiency (PCE) of 20.20%, with a high fill factor (FF) of 81.13%. The average PCE and FF values for 30 devices are 19.03% ± 0.57% and 78.67% ± 2.13%, respectively. The results indicate that this ETL template‐assisted crystallization strategy can be applied to other organometal halide perovskite‐based systems. 相似文献
19.
High-purity black α-phase formamidinium lead iodide (FAPbI3, FA is NH2CHNH+) perovskite polycrystalline film was prepared using low-cost, high-output doctor-blading deposition technique in ambient condition without further annealing process and any additives. The resulting α-phase FAPbI3 perovskite has a large domain size over 200 μm with (00l) preferential crystallographic orientation. The photodetectors with an extremely simple structure were fabricated via doctor-blading, resulting in a responsivity as high as 11.46 AW−1, a ratio of photocurrent/dark current (Ilight/Idark) as large as 105 and a response speed as fast as 5.4 ms. The results suggest that low-cost doctor-blading technique in ambient condition potentially pave a way to eliminate the yellow δ-phase FAPbI3 and get a high-quality black α-FAPbI3 perovskite film, as well as fabricate efficient FAPbI3 perovskite optoelectronic devices. 相似文献
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Recently, there have been extensive research efforts on developing high performance organolead halide based perovskite solar cells. While most studies focused on optimizing the deposition processes of the perovskite films, the selection of the precursors has been rather limited to the lead halide/methylammonium (or formamidium) halide combination. In this work, we developed a new precursor, HPbI3, to replace lead halide. The new precursor enables formation of highly uniform formamidium lead iodide (FAPbI3) films through a one‐step spin‐coating process. Furthermore, the FAPbI3 perovskite films exhibit a highly crystalline phase with strong (110) preferred orientation and excellent thermal stability. The planar heterojunction solar cells based on these perovskite films exhibit an average efficiency of 15.4% and champion efficiency of 17.5% under AM 1.5 G illumination. By comparing the morphology and formation process of the perovskite films fabricated from the formamidium iodide (FAI)/HPbI3, FAI/PbI2, and FAI/PbI2 with HI additive precursor combinations, it is shown that the superior property of the HPbI3 based perovskite films may originate from 1) a slow crystallization process involving exchange of H+ and FA+ ions in the PbI6 octahedral framework and 2) elimination of water in the precursor solution state. 相似文献