Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• the charge carrier mobility (parallel vs perpendicular to the columnar axis) of up to ten orders of magnitude [3][4][5][6][7]. In 1994, Adam and collaborators obtained a hole-mobility of up to 0.1 cm2 V−1 s−1 for a triphenylene-based columnar liquid crystal [8], motivating intense research activity to

• corroborates with the dominant emission of aggregated π–π species in the film observed in the lifetime measurement. The hole mobility of 2 is similar to 1, but its electron mobility is slightly higher, indicating that this pyrene-based molecule can act as an ambipolar transporting layer, in agreement with the

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• been applied in various different molecules, exhibiting outstanding performances in certain applications. The highest hole mobility for organic semiconductors was achieved for thin, crystalline films of 2,7-dioctyl[1]benzothieno[3,2-b][1]-benzothiophene (8), shown in Figure 3, achieving a maximum hole

• only a weak field effect could be measured if no SAMs were used and no annealing was applied, with mobilities in the range 10−7–10−9 cm2 V−1 s−1. The best annealing temperature was 150 °C; mobilities deteriorated if higher or lower annealing temperatures were applied. The best hole mobility of a single

• device was measured upon annealing for 30 minutes at 150 °C with 1.33 × 10−4 cm2 V−1 s−1, using a solution of 10 mg mL−1 in CHCl3 and octadecyltrichlorosilane (OTS) as the SAM [82]. Averaged over seven devices on that wafer, an average hole mobility of 4.69 × 10−5 cm2 V−1 s−1 was measured. However, two

Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96

• applications ranging from organic thin‐film transistors (OTFTs), organic light-emitting diodes (OLEDs), dye‐sensitized solar cells (DSSCs), fluorescent probes, organic photovoltaics (OPVs) to the high hole mobility semiconductors, blue light-emitting materials, nonlinear optical materials and so forth [5][6][7

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• demonstrated maximum external quantum efficiencies up to 3.2%. Keywords: acridan; hole mobility; host; OLED; thermally activated delayed fluorescence; Introduction Organic light emitting diodes (OLEDs) are perfect candidates for multicolor displays and for next generation energy saving large area-lighting

• according to the Poole–Frenkel model µ = µ0 exp(β·E0.5), where µ and µ0 are respectively hole and field-free mobilities, β is the Poole–Frenkel constant, and E is the electric field [31]. The values of hole mobility in the layers of 4 exceeded 10−3 cm2/V·s at electric fields higher than ca. 2.5 × 105 V/cm

• ) formation of a recombination zone near to the light-emitting layer/hole-blocking layer interface due to the unipolar hole mobility of the synthesized hosts; 3) poor balance of holes and electrons in the light-emitting layer, etc. The results obtained suggest that the developed compounds could be more

Two novel blue phosphorescent host materials containing phenothiazine-5,5-dioxide structure derivatives

• Feng-Ming Xie,
• Qingdong Ou,
• Qiang Zhang,
• Jiang-Kun Zhang,
• Guo-Liang Dai,
• Xin Zhao and
• Huai-Xin Wei

Beilstein J. Org. Chem. 2018, 14, 869–874, doi:10.3762/bjoc.14.73

• lifetime. Carbazole groups are widely used in host materials because of their high triplet energy levels and high hole mobility [15]. The Lee group [16] linked carbazolyl groups to diphenyl phosphoramines to design asymmetric (9-phenyl-9H-carbazole-2,5-diyl)bis(diphenylphosphine oxide) (PCPOs) with a

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

• Vinila N. Viswanathan,
• Arun D. Rao,
• Upendra K. Pandey,
• Arul Varman Kesavan and
• Praveen C. Ramamurthy

Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87

• between the units was also observed for the fluorinated polymer P2 due to the enhanced electrostatic interaction between the fluorine substituents and sulfur atoms, leading to a high hole mobility. The use of a fused π-bridge in polymer P3 for the enhancement of the planarity as compared to the P1

• current method (SCLC, see Supporting Information File 1). Hole mobility values of 1.32 × 10−6 cm2/V·s, 4.49 × 10−5 cm2/V·s, and 3.98 × 10−5 cm2/V·s were observed for blends based on P1, P2, and P3, respectively. Compared to the device fabricated using P1, the corresponding devices fabricated with P2 and

• interaction between the polymer chains, which is reflected in the higher hole mobility of P2 over P1. Though the photovoltaic parameter values are very low for these polymers, it was observed that fluorination could increase the overall device performance by ≈110%. The effect of increased planarity along the

Effects of solvent additive on “s-shaped” curves in solution-processed small molecule solar cells

• John A. Love,
• Shu-Hua Chou,
• Ye Huang,
• Guilllermo C. Bazan and
• Thuc-Quyen Nguyen

Beilstein J. Org. Chem. 2016, 12, 2543–2555, doi:10.3762/bjoc.12.249

• GIWAXS. Despite the differences in crystallization, this does not give a clear indication as to the root cause of why devices processed without DIO show signs of space charge and an s-shaped J–V curve. One might expect that the increase in crystallinity has a profound effect on the hole mobility in the

• blends, and space charge may occur due to imbalanced carrier mobilities in the device processed without DIO. However, the hole mobilities for blends processed without DIO and with 1.5% DIO are 5 × 10−5 and 9 × 10−5 cm2/Vs, respectively, each slightly lower than the neat hole mobility of p-SIDT(FBTThCA8)2

Effect of the π-conjugation length on the properties and photovoltaic performance of A–π–D–π–A type oligothiophenes with a 4,8-bis(thienyl)benzo[1,2-b:4,5-b′]dithiophene core

• Ni Yin,
• Lilei Wang,
• Yi Lin,
• Jinduo Yi,
• Lingpeng Yan,
• Junyan Dou,
• Hai-Bo Yang,
• Xin Zhao and
• Chang-Qi Ma

Beilstein J. Org. Chem. 2016, 12, 1788–1797, doi:10.3762/bjoc.12.169

• , the hole mobility of these compounds in blended films was measured using the space-charge-limited current method (SCLC). The device structure studied here was ITO/PEDOT:PSS/COOP-nHT-TBDT:PC61BM/MoO3/Al, and the thin film deposition method is similar to that for solar cell fabrication. The analysis

• method was described in detail in our previous paper [34]. The hole transport mobilities of COOP-nHT-TBDT were measured to be 2.01 × 10−6, 1.81 × 10−6, 4.60 × 10−4 and 8.22 × 10−4 cm2·V−1·s−1 for 1, 2, 3, and 4, respectively. Obviously, the largest molecule 4 displays the highest hole mobility, which

• could be owing to the formation of large crystalline domains in 4:PC61BM blended film, as shown in Figure 5. The high hole mobility for the larger molecules could be one of the reasons for the higher power conversion efficiency for devices based on COOP-nHT-TBDT:PC61BM (Table 2). Long-term stability

3,6-Carbazole vs 2,7-carbazole: A comparative study of hole-transporting polymeric materials for inorganic–organic hybrid perovskite solar cells

• Wei Li,
• Munechika Otsuka,
• Takehito Kato,
• Yang Wang,
• Takehiko Mori and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2016, 12, 1401–1409, doi:10.3762/bjoc.12.134

• the PSCs were also different. The device based on 2,7-Cbz-EDOT showed better photovoltaic properties with the PCE of 4.47% than that based on 3,6-Cbz-EDOT. This could be due to its more suitable highest occupied molecular orbital (HOMO) level and higher hole mobility. Keywords: carbazole polymer

• as its complicated multistep synthesis, low hole mobility in its pristine form, and expensive fabrication costs of the PSCs due to the sublimable small molecule. Accordingly, solution-processable hole-transporting polymers with simple structures have also been pursued as HTMs in the PSCs. Common p

• density (JSC) of 16.5 mA cm−2, open circuit voltage (VOC) of 0.81 V, and fill factor (FF) of 0.33. The lower PCE (3.90%) of the device based on 3,6-Cbz-EDOT was mainly due to the lower JSC (14.7 mA cm−2), which would be reflected in the absorption range and hole mobility of the HTMs [43]. In addition, it

Syntheses of dibenzo[d,d']benzo[2,1-b:3,4-b']difuran derivatives and their application to organic field-effect transistors

• Minh Anh Truong and
• Koji Nakano

Beilstein J. Org. Chem. 2016, 12, 805–812, doi:10.3762/bjoc.12.79

• semiconducting properties [36][37]. For example, dialkyl-substituted anti-DBBDF 3 showed a hole mobility of 0.042 cm2·V−1·s−1 [38]. Recently, we have also found that dinaphtho[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']difuran (anti-DNBDF 4) with a more extended π-conjugation afforded higher hole mobility of 0.33 cm2·V−1

• physical and electrochemical properties of the synthesized compounds are also discussed. OFETs with these compounds as semiconducting layers were found to exhibit relatively high hole mobility of <1.0 × 10−1 cm2·V−1·s−1. Results and Discussion Synthesis The synthetic routes to syn-DBBDF 5 and syn-DNBDF 6

• ), respectively. The FET performance also depends on the substrate temperature during thin-film fabrication. Thus, the highest hole mobility of 1.0 × 10−1 cm2·V−1·s−1 was obtained for the syn-DNBDF-based device fabricated on the HMDS-treated substrate at Tsub = 90 °C, while it was lower than that fabricated with

Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

• Alexander L. Kanibolotsky,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1749–1766, doi:10.3762/bjoc.11.191

• gate configuration [87]. The hole mobility values calculated in the saturated region were found to be 3.8 × 10−2 and 5.3 × 10−2 cm2 V−1 s−1 for OFETs fabricated via spincoating the semiconductor from solution in chlorobenzene and chloroform, respectively. The strong propensity of 48 to aggregation led

Thiazole-induced rigidification in substituted dithieno-tetrathiafulvalene: the effect of planarisation on charge transport properties

• Rupert G. D. Taylor,
• Joseph Cameron,
• Iain A. Wright,
• Neil Thomson,
• Olena Avramchenko,
• Alexander L. Kanibolotsky,
• Anto R. Inigo,
• Tell Tuttle and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1148–1154, doi:10.3762/bjoc.11.129

• the results are summarised in Table 2. The OFETs fabricated using only OTS as the SAM from a chloroform solution show an average saturation hole mobility of 1.35 × 10−5 cm2 V−1 s−1 and an ON/OFF ratio of 101. However, the use of both PFBT and OTS SAMs and a chloroform solution of compound 2 results in

Solution processable diketopyrrolopyrrole (DPP) cored small molecules with BODIPY end groups as novel donors for organic solar cells

• Diego Cortizo-Lacalle,
• Calvyn T. Howells,
• Upendra K. Pandey,
• Joseph Cameron,
• Neil J. Findlay,
• Anto Regis Inigo,
• Tell Tuttle,
• Peter J. Skabara and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2683–2695, doi:10.3762/bjoc.10.283

• organic field-effect transistors [24][25]. The DPP-based conjugated polymers usually show good electron and hole mobility and promising PCE values in OPVs due to large intermolecular interactions through π–π stacking. Nguyen et al. have investigated the DPP core in small molecules for OPVs with excellent

Crystal design using multipolar electrostatic interactions: A concept study for organic electronics

• Peer Kirsch,
• Qiong Tong and
• Harald Untenecker

Beilstein J. Org. Chem. 2013, 9, 2367–2373, doi:10.3762/bjoc.9.272

• unit, but extends also to the four fluorine substituents. This is probably the reason for the significant lateral electron mobility between the adjoining "brick walls" in contrast to the hole mobility which is limited to one contact (A) with particularly strong π–π overlap. In conclusion, 1 can be

Synthesis of oleophilic electron-rich phenylhydrazines

• Aleksandra Jankowiak and
• Piotr Kaszyński

Beilstein J. Org. Chem. 2012, 8, 275–282, doi:10.3762/bjoc.8.29

• columnar rectangular phase (Cr 62 (Colr 60) I), a broad absorption band in the visible region, and redox potentials E0/+11/2 = +0.99 V and E0/−11/2 = −0.45 V versus SCE. Photovoltaic studies of 9 demonstrated hole mobility μh = 1.52 × 10−3 cm2 V−1s−1 in the mesophase with an activation energy Ea = 0.06

Improved syntheses of high hole mobility phthalocyanines: A case of steric assistance in the cyclo-oligomerisation of phthalonitriles

• Daniel J. Tate,
• Rémi Anémian,
• Richard J. Bushby,
• Suwat Nanan,
• Stuart L. Warriner and
• and Benjamin J. Whitaker

Beilstein J. Org. Chem. 2012, 8, 120–128, doi:10.3762/bjoc.8.14

• yield. The phthalocyanine with eight α-isoheptyl substituents gives a high time-of-flight hole mobility of 0.14 cm2·V−1·s−1 within the temperature range of the columnar hexagonal phase, that is 169–189 °C. Keywords: high hole mobility; phthalocyanine; steric assistance; Thorpe–Ingold effect; time-of

• -hexyl derivative from the values reported for the n-heptyl and n-octyl compounds [30]. Time-of-flight photoconductivity The hole mobility for compound 7c was measured in its Colh phase in the temperature range 169–189 °C. Slow cooling of a thin film sandwiched between ITO-coated glass slides readily

• an average of five or more independent measurements. The mobilities were obtained from the slopes of these plots at each temperature. As shown in Figure 3c, the mobility is almost temperature-independent within the mesophase range. The hole mobility of 7c in the Colh phase at 185 °C was found to be