Charge Carrier Mobilities in Amorphous Triphenylamine–Fluorene Copolymers: Role of Triphenylamine Unit in Intra- and Intermolecular Charge Transport

Fukumatsu, Takahiro; Saeki, Akinori; Seki, Shu

doi:10.1143/apex.5.061701

Cited by 7 publications

(6 citation statements)

References 26 publications

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“…The n/i films showed distinct increase of  max and effective lifetime () compared with the single layers (Table 1). This is explained by electron transfer from A 3 Bi 2 I 9 to mp-TiO 2 and retarded charge Therefore, hole transfer is also inefficient and/or TRMC hole mobility of A 3 Bi 2 I 9 is comparable to that of PTAA (~10 -1 cm 2 V -1 s -1 ) [32]. Despite the low hole/electron transfer, the charge recombination is suppressed to some extent, which would merit the solar cell performance.…”

Section: Resultsmentioning

confidence: 99%

Comparative Study of Charge Carrier Dynamics in Bismuth-based Dimer and Double Perovskites

Nishikubo

Saeki

2019

J. Photopol. Sci. Technol.

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From the environmental and economical aspects, the development of less-toxic lead-free perovskite is an imperative challenge for next generation photovoltaics. Although bismuthbased dimer perovskite (A 3 B 2 X 9) and double perovskite (A 2 BB'X 6) (A = cation, B = Bi, B' = Ag, X = halogen) have been considered as the plausible candidates, their power conversion efficiencies (PCE) are still low (~2.2%). In this work, we comparatively evaluated the photoconductivity and charge carrier transfer to electron/hole transport layer (ETL/HTL) in A 3 B 2 X 9 and A 2 BB'X 6 by time-resolved microwave conductivity (TRMC). In contrast to A 3 B 2 X 9 , A 2 BB'X 6 showed much higher photoconductivity and charge transfer efficiency to ETL/HTL. This result is consistent with the PCEs of our photovoltaic devices, in which the double perovskite of Cs 2 AgBiBr 6 exhibited greatly improved fill factor and one order larger photocurrent density than dimer perovskites (Cs 3 Bi 2 I 9 , MA 3 Bi 2 I 9 , and FA 3 Bi 2 I 9 ; MA = methlyammonium cation, FA = formamidinium cation). Our results provide an insight into the key role of photoactive layer and charge transfer process.

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Section: Resultsmentioning

confidence: 99%

Comparative Study of Charge Carrier Dynamics in Bismuth-based Dimer and Double Perovskites

Nishikubo

Saeki

2019

J. Photopol. Sci. Technol.

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“…0.1. Investigations on fluorene-triphenylamine copolymers or poly(carbazole)s using TRMC and SCLC suggested that α is around 0.1–0.3. Meanwhile, a wide range of μ DC values are reported for the low band copolymers, for example, PCDTBT hole mobilities varied by 3 orders of magnitude from 8.9 × 10 –6 cm 2 V –1 s –1 , 1.5–9.6 × 10 –4 cm 2 V –1 s –1 , to 8 × 10 –3 cm 2 V –1 s –1 , depending on measurement technique, solvent, annealing temperature, p/n blend ratio, and so on.…”

Section: Resultsmentioning

confidence: 99%

A Versatile Approach to Organic Photovoltaics Evaluation Using White Light Pulse and Microwave Conductivity

et al. 2012

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State-of-the-art low band gap conjugated polymers have been investigated for application in organic photovoltaic cells (OPVs) to achieve efficient conversion of the wide spectrum of sunlight into electricity. A remarkable improvement in power conversion efficiency (PCE) has been achieved through the use of innovative materials and device structures. However, a reliable technique for the rapid screening of the materials and processes is a prerequisite toward faster development in this area. Here we report the realization of such a versatile evaluation technique for bulk heterojunction OPVs by the combination of time-resolved microwave conductivity (TRMC) and submicrosecond white light pulse from a Xe-flash lamp. Xe-flash TRMC allows examination of the OPV active layer without requiring fabrication of the actual device. The transient photoconductivity maxima, involving information on generation efficiency, mobility, and lifetime of charge carriers in four well-known low band gap polymers blended with phenyl-C(61)-butyric acid methyl ester (PCBM), were confirmed to universally correlate with the PCE divided by the open circuit voltage (PCE/V(oc)), offering a facile way to predict photovoltaic performance without device fabrication.

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“…The same batch of FT37, FT55, and FT73 from our previous report was used. 70 A 50 nm-thick HTL of conjugated polymer with/ without LiTFSI (TCI) and TBP (TCI) dopants (polymer:-LiTFSI = 1:0.15) was spin-coated from a toluene solution (ca. polymer: 10 mg mL −1 , TBP: 15 μL mL −1 ) at an appropriate rotation speed depending on the viscosity of each polymer solution.…”

Section: Acs Photonicsmentioning

confidence: 99%

“…Conjugated polymers of P3HT, MDMO-PPV, F8T2, and PTAA were purchased from Aldrich, while TQ1 was from Luminescence Technology Corp. The same batch of FT37, FT55, and FT73 from our previous report was used . A 50 nm-thick HTL of conjugated polymer with/without LiTFSI (TCI) and TBP (TCI) dopants (polymer:LiTFSI = 1:0.15) was spin-coated from a toluene solution (ca.…”

Section: Experimental Sectionmentioning

confidence: 99%

Quantifying Hole Transfer Yield from Perovskite to Polymer Layer: Statistical Correlation of Solar Cell Outputs with Kinetic and Energetic Properties

2016

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Organic–inorganic hybrid perovskites provide not only an exceptionally rich area of research but also remarkable power conversion efficiency relevant to commercial use. However, developing efficient organic hole transport layers remains challenging, due partly to the subtle electronic behavior of perovskite and complications introduced by the use of reactive dopants. Here we show, through time-resolved microwave conductivity, the quantification of a hole transfer process from methylammonium lead triiodide perovskite to eight kinds of conjugated polymers with and without a Li dopant. The time evolution of hole transfer yield is characterized by kinetic parameters, which are further examined in conjunction with solar cell performance, energetics, and temporal profiles triggered by exposure to air at the minute scale. Using statistics and LASSO (least absolute shrinkage and selection operator) analysis, we identify an accurate descriptor that correlates with device output. This work explores the design of organic hole transport materials, and the presented evaluation technique may be employed as a facile screening method.

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Charge Carrier Mobilities in Amorphous Triphenylamine–Fluorene Copolymers: Role of Triphenylamine Unit in Intra- and Intermolecular Charge Transport

Cited by 7 publications

References 26 publications

Comparative Study of Charge Carrier Dynamics in Bismuth-based Dimer and Double Perovskites

Comparative Study of Charge Carrier Dynamics in Bismuth-based Dimer and Double Perovskites

A Versatile Approach to Organic Photovoltaics Evaluation Using White Light Pulse and Microwave Conductivity

Quantifying Hole Transfer Yield from Perovskite to Polymer Layer: Statistical Correlation of Solar Cell Outputs with Kinetic and Energetic Properties

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