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14965-49-2Relevant articles and documents
3,4-Phenylenedioxythiophene (PheDOT) Based Hole-Transporting Materials for Perovskite Solar Cells
Chen, Jian,Chen, Bai-Xue,Zhang, Fang-Shuai,Yu, Hui-Juan,Ma, Shuang,Kuang, Dai-Bin,Shao, Guang,Su, Cheng-Yong
, p. 1043 - 1049 (2016)
Two new electron-rich molecules based on 3,4-phenylenedioxythiophene (PheDOT) were synthesized and successfully adopted as hole-transporting materials (HTMs) in perovskite solar cells (PSCs). X-ray diffraction, absorption spectra, photoluminescence spectra, electrochemical properties, thermal stabilities, hole mobilities, conductivities, and photovoltaic parameters of PSCs based on these two HTMs were compared with each other. By introducing methoxy substituents into the main skeleton, the energy levels of PheDOT-core HTM were tuned to match with the perovskite, and its hole mobility was also improved (1.33×10-4 cm2 V-1 s-1, being higher than that of spiro-OMeTAD, 2.34×10-5 cm2 V-1 s-1). The PSC based on MeO-PheDOT as HTM exhibits a short-circuit current density (Jsc) of 18.31 mA cm-2, an open-circuit potential (Voc) of 0.914 V, and a fill factor (FF) of 0.636, yielding an encouraging power conversion efficiency (PCE) of 10.64 % under AM 1.5G illumination. These results give some insight into how the molecular structures of HTMs affect their performances and pave the way for developing high-efficiency and low-cost HTMs for PSCs.
Highly stable and Pb-free bismuth-based perovskites for photodetector applications
Bhorde, Ajinkya,Nair, Shruthi,Borate, Haribhau,Pandharkar, Subhash,Aher, Rahul,Punde, Ashvini,Waghmare, Ashish,Shinde, Pratibha,Vairale, Priti,Waykar, Ravindra,Doiphode, Vidya,Jadkar, Vijaya,Hase, Yogesh,Rondiya, Sachin,Patil, Nilesh,Prasad, Mohit,Jadkar, Sandesh
, p. 11282 - 11290 (2020)
Herein, we report the synthesis of highly stable, Pb-free bismuth iodide (BiI3 or BI), stoichiometric methylammonium bismuth iodide [(CH3NH3)3Bi2I9 or MA3Bi2I9 or s-MBI] and non-stoichiometric methylammonium bismuth iodide [(CH3NH3)2BiI5 or MA2BiI5 or Ns-MBI] perovskite thin films for photodetector applications. These films are synthesized at room temperature by a single step solution process spin coating method. The structural, optical, and morphological properties of these films were investigated using different characterization techniques such as XRD, Raman spectroscopy, FE-SEM, UV-Visible spectroscopy, etc. Formation of BI, s-MBI and Ns-MBI thin films is confirmed by XRD and Raman spectroscopy measurements. XRD analysis reveals that BI has a hexagonal crystal structure and a P63/mmc hexagonal space group for s-MBI and Ns-MBI. The optical properties of BI thin films show a high absorption coefficient (～104 cm-1) and a band gap of ～1.74 eV. Similarly, s-MBI films have a high absorption coefficient (～103 cm-1) and an indirect band gap of ～1.8 eV. Moving from s-MBI to Ns-MBI, the value of absorption coefficient is ～103 cm-1 and the band gap corresponds to ～2 eV. Finally, photodetectors based on the synthesized BI, s-MBI and Ns-MBI perovskites have been directly fabricated on FTO substrates. All photodetectors exhibited highly stable photo-switching behaviour along with excellent photoresponsivity and detectivity, with a fast response and recovery time. Our work demonstrates that Pb-free BI, s-MBI and Ns-MBI perovskites have great potential in the future for realizing stable photodetectors.
Surface Photovoltage Spectroscopy Study of Ultrasonically Sprayed-Aerosol CH3NH3PbI3 Perovskite Crystals
Henjongchom, Nakorn,Rujisamphan, Nopporn,Tang, I-Ming,Supasai, Thidarat
, (2018)
A simple deposition process for preparing crystalline semiconductors with low degrees of disorder is of paramount interest for both device applications and research investigations. This study centers on the ultrasonically sprayed-aerosol based approach for preparing crystals of methylammonium lead trihalide perovskite (CH3NH3PbI3). The surface photovoltage (SPV) spectra are found to depend strongly on the preparation conditions, with the SPV signals (below the material's band gap) providing information on the defect states. The measured values of tail states near the band gap (Et) are found to be about 21 and 52 meV for the CH3NH3PbI3 crystals prepared by the ultrasonically sprayed-on and spun casting approaches, respectively.
The role of chlorine in the formation process of CH3NH3PbI3-xClx perovskite
Yu, Hui,Wang, Feng,Xie, Fangyan,Li, Wenwu,Chen, Jian,Zhao, Ni
, p. 7102 - 7108 (2014)
CH3NH3PbI3-xClx is a commonly used chemical formula to represent the methylammonium lead halide perovskite fabricated from mixed chlorine- and iodine-containing salt precursors. Despite the rapid progress in improving its photovoltaic efficiency, fundamental questions remain regarding the atomic ratio of Cl in the perovskite as well as the reaction mechanism that leads to its formation and crystallization. In this work we investigated these questions through a combination of chemical, morphological, structural and thermal characterizations. The elemental analyses reveal unambiguously the negligible amount of Cl atoms in the CH3NH3PbI3-xClx perovskite. By studying the thermal characteristics of methylammonium halides as well as the annealing process in a polymer/perovskite/FTO glass structure, we show that the formation of the CH3NH3PbI3-xClx perovskite is likely driven by release of gaseous CH3NH3Cl (or other organic chlorides) through an intermediate organometal mixed halide phase. Furthermore, the comparative study on CH3NH3I/PbCl2 and CH3NH3I/PbI2 precursor combinations with different molar ratios suggest that the initial introduction of a CH3NH3+ rich environment is critical to slow down the perovskite formation process and thus improve the growth of the crystal domains during annealing; accordingly, the function of Cl- is to facilitate the release of excess CH3NH3+ at a relatively low annealing temperatures.
Control of Perovskite Crystal Growth by Methylammonium Lead Chloride Templating
Binek, Andreas,Grill, Irene,Huber, Niklas,Peters, Kristina,Hufnagel, Alexander G.,Handloser, Matthias,Docampo, Pablo,Hartschuh, Achim,Bein, Thomas
, p. 1199 - 1204 (2016)
State-of-the-art solar cells based on methylammonium lead iodide (MAPbI3) now reach efficiencies over 20 %. This fast improvement was possible with intensive research in perovskite processing. In particular, chloride-based precursors are known to have a positive influence on the crystallization of the perovskite. Here, we used a combination of in-situ X-ray diffraction and charge-transport measurements to understand the influence of chloride during perovskite crystallization in planar heterojunction solar cells. We show that MAPbCl3 crystallizes directly after the deposition of the starting solution and acts as a template for the formation of MAPbI3. Additionally, we show that the charge-carrier mobility doubles by extending the time for the template formation. Our results give a deeper understanding of the influence of chloride in the synthesis of MAPbI3 and illustrate the importance of carefully controlling crystallization for reproducible, high-efficiency solar cells.
Thermally induced recrystallization of MAPbI3 perovskite under methylamine atmosphere: An approach to fabricating large uniform crystalline grains
Jacobs, Daniel L.,Zang, Ling
, p. 10743 - 10746 (2016)
A liquid to solid phase transition of methylammonium lead triiodide (MAPbI3) under methylamine (MA) atmosphere at elevated temperatures was discovered, and used to form high quality and uniform thin films containing large, low defect crystal grains tens of microns in size.
Exploration of organic-inorganic hybrid perovskites for surface-enhanced infrared spectroscopy of small molecules
Chen, Jia,Mo, Zhi-Hong,Yang, Xiao,Zhou, Hai-Ling,Gao, Qin
, p. 6949 - 6952 (2017)
The organic-inorganic hybrid perovskites efficiently enhance the infrared absorption of small molecules. It is suggested that the quantum wells of perovskites enable the electrons of the perovskites to be excited by light in the infrared region. The exploration has opened a new path for chemical sensing through infrared spectroscopy.
Self-powered, ultraviolet-visible perovskite photodetector based on TiO2 nanorods
Zhou, Hai,Song, Zehao,Tao, Pan,Lei, Hongwei,Gui, Pengbin,Mei, Jun,Wang, Hao,Fang, Guojia
, p. 6205 - 6208 (2016)
A self-powered, ultraviolet-visible perovskite photodetector based on TiO2 nanorods/CH3NH3PbI3 heterojunction was reported. We found that the device showed good photovoltaic properties with a short-circuit current density of 17.83 mA cm-2, an open-circuit voltage of 0.76 V and a fill factor of 51.34%, leading to a PCE of 6.95%. Based on the wide band gap and the perovskite supporting part of the TiO2 nanorods, the device showed good ultraviolet-visible photo-response characteristics with the responsivity at zero bias reaching ～0.26 and 0.85 A W-1 at 364 and 494 nm, respectively. These results present potential applications of TiO2/perovskite photodetectors in ultraviolet and visible regions.
Nanostructured TiO2/CH3NH3PbI3 heterojunction solar cells employing spiro-OMeTAD/Co-complex as hole-transporting material
Noh, Jun Hong,Jeon, Nam Joong,Choi, Yong Chan,Nazeeruddin, Md. K.,Graetzel, Michael,Seok, Sang Il
, p. 11842 - 11847 (2013)
For using 2,2′,7,7′-tetrakis(N,N′-di-p- methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD) as a hole conductor in solar cells, it is necessary to improve its charge-transport properties through electrochemical doping. With the aim of fabricating efficient mesoscopic TiO2/CH3NH3PbI3 heterojunction solar cells, we used tris[2-(1H-pyrazol-1-yl)-4-tert- butylpyridine)cobalt(iii) tris(bis(trifluoromethylsulfonyl) imide)] (FK209) as a p-dopant for spiro-OMeTAD. The mixture of spiro-OMeTAD, FK209, lithium bis(trifluoromethylsulfonyl)imide (Li-TFSI), and 4-tert-butylpyridine (TBP) exhibited significantly higher performance than mixtures of pristine spiro-OMeTAD, spiro-OMeTAD, and FK209, and spiro-OMeTAD, Li-TFSI, and TBP. Such a synergistic effect between the Co-complex and Li-TFSI in conjunction with spiro-OMeTAD effectively improved the power conversion efficiency (PCE) of the fabricated solar cells. As a result, we achieved PCE of 10.4%, measured under standard solar conditions (AM 1.5G, 100 mW cm-2).
Realize larger grain size of CH3NH3PbI3 film with reduced non-radiative recombination for high performance perovskite solar cells via precursor colloidal size engineering
Chen, Xuelian,Jiang, Hao,Li, Guangrong,Li, Yan,Sun, Can,Zhang, Xiaoyong,Zheng, Jialu
, (2021)
In CH3NH3PbI3 perovskite solar cells, enhancement grain size of CH3NH3PbI3 to reduce the non-radiative at grain boundaries is an important way to reach high performance perovskite solar cell. However, it is still a challenge to enhance the grain size of CH3NH3PbI3 through a simple and low cost way. In this work, a larger precursor colloidal size is realized through tuning morphology of precursor CH3NH3I using a polar solvent of ethanol during purification, yielding a larger grain size of CH3NH3PbI3 film, and the as-prepared perovskite solar cells are shown to be dramatically increased to 17.49% with an increase in short circuit density, fill factor and open circuit voltage, as compared to that (14.28%) in the control device with CH3NH3I purified by non-polar solvent of diethyl ether. The investigation result showed the increased efficiency of perovskite solar cells prepared by ethanol purification is ascribed to a faster charge transfer at CH3NH3PbI3/TiO2 interface resulting from the reduced grain boundary defects. Our work provides a route for improving the CH3NH3PbI3 device efficiency through a simple yet effective approach.
