Space Charge and Carrier Trapping Effects on the Transient Photocurrents of Organic Materials Using the Time-of-Flight Technique

Cusumano, Pasquale; Gambino, Salvatore

doi:10.1007/s11664-007-0349-4

Cited by 25 publications

(12 citation statements)

References 19 publications

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“…To understand the charge-carrier transport properties of these HTMs, their hole mobility values (m h )w ere determined from transit times (t T ,F igure S3) using the equation: m = d 2 / Vt T , [43] where d is the organic film thickness and V is the applied voltage. At room temperature, m h of Z33, Z34, and Z35 are 4.67 10 À4 ,7 .46 10 À4 ,a nd 2.76 10 À4 cm 2 V À1 s À1 under the electric field of 1.0 10 5 Vcm À1 ,r espectively.A ll three new HTMsh ave higher m h than pristine spiro-OMeTAD (1.76 10 À4 cm 2 V À1 s À1 at the electric field of 1.0 10 5 Vcm À1 ), which is consistentw ith previouslyr eported data (2 10 À4 cm 2 V À1 s À1 at the electric field of 2.6 10 5 Vcm À1 ).…”

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confidence: 99%

Dopant‐Free Donor (D)–π–D–π–D Conjugated Hole‐Transport Materials for Efficient and Stable Perovskite Solar Cells

Liu

et al. 2016

ChemSusChem

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Abstract:Three novel hole transporting materials (HTM) using the 4-Methoxytriphenylamine (MeOTPA) core were designed and synthesized.The HTMs energy levels were tuned to match with perovskite by introducing electron donating groups symmetrically linked with olefinic bonds as the π bridge. The CH 3 NH 3 PbI 3 -based perovskite solar cells exhibited a remarkable overall power conversion efficiency (PCE) of 16.1 % without any dopants and additives based on 4-((E)-4-(bis(4-methoxyphenyl)amino)styryl)-N-(4-((E)-4-(bis(4methoxyphenyl)amino)styryl)phenyl)-N-(4-methoxyphenyl)aniline (Z34) , which is comparable to 16.7 % obtained by p-doped spiro-OMeTAD-based device. Importantly, the devices based-on three HTMs show relatively better stability compared to devices based on spiro-OMeTAD when aged under ambient air of 30% relative humidity in the dark. 2Increasing energy demands and concerns about global warming drive the exploration of clean, inexpensive and renewable energy sources. Recently, the photovoltaic community has witnessed a rapid emergence of a new class of solid-state heterojunction solar cells based on solution-processable organometal halide perovskite absorbers [1][2][3] . The power conversion efficiency (PCE) of solid-state perovskite solar cells (PSCs) has been quickly increased to over 20% [4][5][6] because of their unique characteristics, such as a broad spectral absorption range, large absorption coefficient, high charge carrier mobility and long diffusion length.[2]In the configuration of a PSC, the hole transporting material (HTMs) plays the key role of promoting hole migration, as well as preventing internal charge recombination. [7] A great number of HTMs have been developed and applied in PSCs, including various newly designed, inorganic p-type semiconductors, conducting polymers, as well as small molecule hole conductors [8] . 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD) that was well studied in solid state DSCs, continues to exhibit high performance in PSCs. Due to its relatively low hole mobility and its tedious synthesis strongly correlated to its production cost, numerous alternative HTMs have been explored with an aim to replace such a material [9][10][11][12][13][14][15][16][17][18][19][20] . Although inorganic HTMs (CuI and CuSCN) have drawn much attention due to their high hole mobilities and low production cost [21] ,polymeric HTMs, such as conjugated polytriarylamine (PTAA) [22] , poly(3-hexylthiophene-2,5-diyl) (P3HT) [23] etc., have also shown competitive performances in PSCs, small molecular HTMs have advantages of their convenient purification, controllable molecular structures and relatively high efficiency [24] .Regarding small molecule HTMs incorporated with dopants, the PCE of the dopant-free HTM based devices are consistently lying between 10% to 13% [25][26][27][28][29][30][31][32][33][34][35][36] , few are over 15%. [37][38][39][40] Herein, we report the synthesis and characterization of three novel dopant-free 4-Methoxytriphenylamine (Me...

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confidence: 99%

Dopant‐Free Donor (D)–π–D–π–D Conjugated Hole‐Transport Materials for Efficient and Stable Perovskite Solar Cells

Liu

et al. 2016

ChemSusChem

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“…An investigation into possible electron deep trapping within the bulk of the materials was carried out by comparing averaged and single pulse photocurrents. A technique known as immobile space charge neutralization15 was used to neutralize the effects of any trapping. This consists of repeated illumination of the sample with grounded electrodes.…”

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confidence: 99%

Limitation of Discharge Capacity and Mechanisms of Air‐Electrode Deactivation in Silicon–Air Batteries

et al. 2012

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The electrocatalytical process at the air cathode in novel silicon-air batteries using the room-temperature ionic liquid hydrophilic 1-ethyl-3-methylimidazolium oligofluorohydrogenate [EMI⋅2.3 HF⋅F] as electrolyte and highly doped silicon wafers as anodes is investigated by electrochemical means, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR) spectroscopy. The results obtained by XPS and EPR provide a model to describe the limited discharge capacity by means of a mechanism of air-electrode deactivation. In that respect, upon discharge the silicon-air battery's cathode is not only blocked by silicon oxide reduction products, but also experiences a major modification in the MnO₂ catalyst nature. The proposed modification of the MnO₂ catalyst by means of a MnF₂ surface layer greatly impacts the Si-air performance and describes a mechanism relevant for other metal-air batteries, such as the lithium-air. Moreover, the ability for this deactivation layer to form is greatly impacted by water in the electrolyte.

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“…Noteworthy that ToF is the established electrical measurement used for determining carrier mobility of films [20][21][22][23][24]. electrode charging appeared just after the applied voltage value jumped from 0 V to the target value, and it was followed by carrier injection and succeeding carrier transport.…”

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confidence: 99%

Study of carrier-mobility of organic thin film by dark-injection time-of-flight and electric-field-induced optical second-harmonic generation measurements

Sunaga

Taguchi

et al. 2017

Chemical Physics Letters

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Space Charge and Carrier Trapping Effects on the Transient Photocurrents of Organic Materials Using the Time-of-Flight Technique

Cited by 25 publications

References 19 publications

Dopant‐Free Donor (D)–π–D–π–D Conjugated Hole‐Transport Materials for Efficient and Stable Perovskite Solar Cells

Dopant‐Free Donor (D)–π–D–π–D Conjugated Hole‐Transport Materials for Efficient and Stable Perovskite Solar Cells

Limitation of Discharge Capacity and Mechanisms of Air‐Electrode Deactivation in Silicon–Air Batteries

Study of carrier-mobility of organic thin film by dark-injection time-of-flight and electric-field-induced optical second-harmonic generation measurements

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