Thermal vapor condensation of uniform graphitic carbon nitride films with remarkable photocurrent density for photoelectrochemical applications

Bian, Juncao; Li, Qian; Huang, Chao; Li, Jianfu; Guo, Yao; Zaw, Myowin; Qi, Fei

doi:10.1016/j.nanoen.2015.04.012

Cited by 225 publications

(230 citation statements)

References 29 publications

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“…High extinction coefficients in polymeric semiconductors are mostly due to a very high density of states and high transition dipole moments and were recently also attributed to high orientation and high stiffness of the polymer chains . The extinction coefficient reveals a pronounced absorption shoulder at about 3.37 eV (λ ≈ 370 nm) attributed to π–π* transitions, in good agreement with bulk pCN (Figure S9, Supporting Information) and previous reports on pCN thin films . However, we cannot exclude at this stage also a minor contribution to the absorption due to trap states.…”

supporting

confidence: 87%

“…The excitation versus emission contour plot shows that for the peak wavelength of photoluminescence emission, i.e., 466 nm, two main excitation modes with maxima at 275 and 375 nm are present. The two excitation maxima are attributed to π–π* electronic transitions in pCN thin films, whereas, the lone pair‐π* transition appears as a shoulder at about 394 nm . However, the emission processes in pCN are complex and still under debate in the scientific community .…”

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confidence: 99%

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Shine Bright Like a Diamond: New Light on an Old Polymeric Semiconductor

et al. 2020

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Brilliance usually refers to the light reflected by the facets of a gemstone such as diamond due to its high refractive index. Nowadays, high‐refractive‐index materials find application in many optical and photonic devices and are mostly of inorganic nature. However, these materials are usually obtained by toxic or expensive production processes. Herein, the synthesis of a thin‐film organic semiconductor, namely, polymeric carbon nitride, by thermal chemical vapor deposition is presented. Among polymers, this organic material combines the highest intrinsic refractive index reported so far with high transparency in the visible spectrum, even reaching the range of diamond. Eventually, the herein presented deposition of high quality thin films and their optical characteristics open the way for numerous new applications and devices in optics, photonics, and beyond based on organic materials.

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Shine Bright Like a Diamond: New Light on an Old Polymeric Semiconductor

et al. 2020

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“…[23][24][25] Lately, we have succeeded to sensitize TiO 2 with C 3 N 4 by in situ deposition method that resulted in the formation of direct chemical bond between the TiO 2 and the C 3 N 4 . [23][24][25] Lately, we have succeeded to sensitize TiO 2 with C 3 N 4 by in situ deposition method that resulted in the formation of direct chemical bond between the TiO 2 and the C 3 N 4 .…”

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Toward Efficient Carbon Nitride Photoelectrochemical Cells: Understanding Charge Transfer Processes

Albero

Barea

et al. 2016

Adv Materials Inter

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to the necessity to establish a direct contact between the active materials (C 3 N 4 ) and the wide band gap semiconductor and the need of interparticle charge migration to the electrode. [23][24][25] Lately, we have succeeded to sensitize TiO 2 with C 3 N 4 by in situ deposition method that resulted in the formation of direct chemical bond between the TiO 2 and the C 3 N 4 . The intimate contact between TiO 2 and C 3 N 4 led to the absorption extension to longer wavelengths due to creation of new energy transfer paths between the materials. Moreover, the TiO 2 /C 3 N 4 system exhibited promising photocurrent densities in the presence of polysulfide as the redox electrolyte. [26] However, in comparison to the theoretical current densities the performances of this system are still low. In order to improve the cell performance, the understanding of the charge transfer reactions that limit the PEC efficiency, especially in the photoanode, is highly desired.Herein, we studied the charge recombination process between C 3 N 4 and mesoporous TiO 2 in a photoelectrode configuration using laser transient absorption spectroscopy (L-TAS). In addition, we determined the electron injection rate from the C 3 N 4 excited states to the TiO 2 conduction band by steady state and time resolved photoluminescence. Finally, the hole extraction kinetics using various liquid electrolytes and solid state hole conductors were also studied in detail. Our measurements indicate that the photoexcited electrons from C 3 N 4 can be efficiently injected to the TiO 2 conduction band, the recombination between electrons and holes from the TiO 2 conduction band and the C 3 N 4 valence band, respectively, is found to be relatively slow, thus allowing long-live charge separation. However, the hole transfer to the electrolyte was found to be the limiting process during the PEC operation. This understanding of the processes taking place within C 3 N 4 /TiO 2 photoanode can lead to the efficient C 3 N 4 -based PEC cells and photovoltaics solar cell via rational selection of hole conductor and smart electrode design.The C 3 N 4 electrodes were prepared according to our previous report. [26] Briefly, the C 3 N 4 was deposited onto mesoporous TiO 2 (which was grown on FTO glass) and nonconductive glass, respectively, by using cyanuric acid-melamine (CM) supramolecular complex as the precursor. The CM precursor was placed on top of TiO 2 electrodes or glass, totally covering the substrates and afterward the system was heated to 550 °C under nitrogen atmosphere (see also Figures S1 and S2, Supporting Information). After that the electrodes were fully characterized by a range of techniques. [26]

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“…[85] Der In-situ-Gastransportmechanismus erlaubt eine vollständige Beschichtung des mesoporçsen TiO 2 -Films durch Erhitzen von pulverfçrmigen Vorstufen, die nur mit der Oberfläche des Films in Kontakt stehen. [53,86,87] Die Kondensation eines supramolekularen Komplexes wurde auch zwischen zwei Elektroden unter einer inerten Atmosphäre durchgeführt. B. Fehlen von sogenannten Pinholes,d.h.…”

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Kohlenstoffnitridmaterialien für photochemische Zellen zur Wasserspaltung

et al. 2019

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Graphitische Kohlenstoffnitridmaterialien (CN) sind aufgrund ihrer einstellbaren Bandlücke, geeigneten Energiebandposition, hohen Stabilität unter harschen chemischen Bedingungen und geringen Kosten interessante Photokatalysatoren und heterogene Katalysatoren für zahlreiche Reaktionen. Allerdings befindet sich die Nutzung von CN in photoelektrochemischen (PEC) und photoelektronischen Bauelementen noch in einem frühen Stadium, da die Abscheidung einer hochwertigen und homogenen CN‐Schicht auf Substraten, die breite Bandlücke, die schlechte Ladungstrennungseffizienz sowie die geringe elektronische Leitfähigkeit noch Schwierigkeiten bereiten. In diesem Kurzaufsatz diskutieren wir Synthesewege zur Herstellung verschiedener Strukturen von CN auf Substraten und deren grundlegende photophysikalische Eigenschaften und photoelektrochemische Aktivität. Wir beschreiben die wesentlichsten Herausforderungen bei der Einbindung von CN in PEC‐Zellen sowie mögliche Wege zur Überwindung der bestehenden Beschränkungen zur Integration von CN‐Materialien in PEC und andere photoelektronische Bauelemente.

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Thermal vapor condensation of uniform graphitic carbon nitride films with remarkable photocurrent density for photoelectrochemical applications

Cited by 225 publications

References 29 publications

Shine Bright Like a Diamond: New Light on an Old Polymeric Semiconductor

Shine Bright Like a Diamond: New Light on an Old Polymeric Semiconductor

Toward Efficient Carbon Nitride Photoelectrochemical Cells: Understanding Charge Transfer Processes

Kohlenstoffnitridmaterialien für photochemische Zellen zur Wasserspaltung

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