Organic electron transport materials

• Joseph Cameron and
• Peter J. Skabara

Beilstein J. Org. Chem. 2024, 20, 672–674, doi:10.3762/bjoc.20.60

• soluble in ethyl acetate, a green solvent, and solution-processed for PM6:Y6 bulk-heterojunction solar cells with power conversion efficiency > 13% [6]. In addition to orthogonal processing, it has been shown that treatment with base [7] or photo-crosslinking [8] can insolubilise solution-processed layers

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• phenyl-C61-butyric acid methyl ester (PCBM) acceptor when used in bulk heterojunction polymer solar cell devices with poly(3-hexylthiophene) (P3HT) as the donor material. This improvement was attributed to the anchoring effect of the bulkier groups present in TQT-C60, which hindered the movement and

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

• Kathryn M. Wolfe,
• Shahidul Alam,
• Eva German,
• Fahad N. Alduayji,
• Maryam Alqurashi,
• Frédéric Laquai and
• Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

• ethyl acetate, while using a bulk heterojunction (BHJ) comprised of PM6:Y6. High power conversion efficiencies (PCEs) of 13% were achieved compared to control devices using the standard PFN-Br CIL. Keywords: cathode interlayer materials; green solvent processing; organic photovoltaics; Introduction

• the past several decades, which resulted in power conversion efficiencies (PCEs) of OPVs reaching over 19% by using state-of-the-art organic photoactive materials in conjunction with hole and electron transporting “interlayers” that reside between the bulk heterojunction (BHJ) and the electrodes [6

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• azulene density (75 mol % azulene) was found to be an effective cathode modification layer in a bulk-heterojunction solar cell with a power conversion efficiency of 7.9%. Conclusion This review has described the chemical syntheses and key features of azulene-containing polymers reported in the last three

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• in chloroform shows typical resonance signals of six hydrogen-bonded protons (Scheme 44) [162]. In order to improve the optical absorption of fullerene acceptors for utilization in solar cells with a bulk heterojunction, a series of dye–fullerene dyads with strong absorption in the visible region was

Synthesis of aryl-substituted thieno[3,2-b]thiophene derivatives and their use for N,S-heterotetracene construction

• Nadezhda S. Demina,
• Nikita A. Kazin,
• Nikolay A. Rasputin,
• Roman A. Irgashev and
• Gennady L. Rusinov

Beilstein J. Org. Chem. 2019, 15, 2678–2683, doi:10.3762/bjoc.15.261

• light-harvesting dyes for dye-sensitized solar cells [1], electron-donating materials for bulk heterojunction solar cells [2][3][4], and p-type semiconductors for organic field-effect transistors [5][6][7]. Within the same context of organic semiconductor development, the bicyclic TT subunit has been

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• organic counterpart, i.e., bulk heterojunction solar cells, or other hybrid PV technologies such as perovskite solar cells. DSSCs can display satisfactory power conversion efficiencies (PCE) in the range of 10 to 14% [1][2][3] but also a long-term stability when specific electrolytes based on ionic

• even bulk heterojunction solar cells [19][20] or DSSCs [21][22]. In this articl we report an innovative synthetic approach for synthesizing 2,3,5,6-tetramethyl-BODIPY compounds and a way to further functionalize such cores has been developed. The optoelectronic properties of the functional molecules

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

• backbone was also studied. This enhanced planarity led to the highest observed mobility among the reported three polymers as well as to an improvement in the device efficiency by more than 40% for P3. Keywords: bulk heterojunction; donor–acceptor–donor polymer; low band gap polymer; organic photovoltaics

• OPV devices led to a new type of device, the so-called bulk heterojunction (BHJ) solar cells, with improved power-conversion efficiency (PCE) [2][3][4]. A large number of polymer semiconducting materials of donor–acceptor–donor (D–A–D) architecture have been synthesized and used in OPV devices

• OPVs based on bulk heterojunction (BHJ) solar cells of polymers P1, P2 and P3 and tested them with PC70BM as an acceptor. The device architecture of the BHJ solar cell was ITO/PEDOT:PSS (40 nm)/polymer:PC70BM (120 nm)/Ca (15 nm)/Al (100 nm). Figure 6 shows the favorable energy alignments for both

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

• , National Taiwan University, Taipei, 10617, Taiwan 10.3762/bjoc.12.249 Abstract A novel molecular chromophore, p-SIDT(FBTThCA8)2, is introduced as an electron-donor material for bulk heterojunction (BHJ) solar cells with broad absorption and near ideal energy levels for the use in combination with common

• mixed with PC71BM and cast to form a bulk heterojunction (BHJ) atop poly(3,4-ethylenedioxythiophene) polystyrene sulfate (PEDOT) giving an architecture of ITO/PEDOT/p-SIDT(FBTThCA8)2:PC71BM/Ca/Al. The mass ratio of p-SIDT(FBTThCA8)2:PC71BM was held at 1:1 and cast from a chlorobenzene solution

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• devices with PTB7-Th resulting in high-performance OPV devices with up to 10.7% PCE. Keywords: molecular materials; nematic liquid crystal; organic solar cells; organic synthesis; p-type organic semiconductors; small molecule; Introduction Bulk heterojunction (BHJ) organic solar cells (OSC), a blend of

• trend as the observed values determined by CV and PESA. Photovoltaic performances. The BXxR series of materials were incorporated into bulk heterojunction devices with a conventional architecture, i.e. ITO/PEDOT:PSS/active layer/Ca/Al (Figure 12a). The active layer composition was held at 1:1

Comparing blends and blocks: Synthesis of partially fluorinated diblock polythiophene copolymers to investigate the thermal stability of optical and morphological properties

• Pierre Boufflet,
• Sebastian Wood,
• Jessica Wade,
• Zhuping Fei,
• Ji-Seon Kim and
• Martin Heeney

Beilstein J. Org. Chem. 2016, 12, 2150–2163, doi:10.3762/bjoc.12.205

• collection. With the thermal stability of all-polymer and polymer-fullerene blend microstructures being particularly problematic [19], block copolymers present a potential solution. Indeed, it has been shown that when block copolymers are used as additives in bulk heterojunction donor–acceptor blend layers

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

• Forrest S. Etheridge,
• Roshan J. Fernando,
• Sandra Pejić,
• Matthias Zeller and
• Geneviève Sauvé

Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182

• the reader to observe the intermolecular packing on their own using the cif file provided as Supporting Information File 2. Preliminary results in OPVs To test the potential of the new fluorinated zinc(II) complexes as electron acceptor, we fabricated bulk heterojunction OPVs in the inverted

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

• performance Bulk heterojunction (BHJ) solar cells with a device structure of ITO/PEDOT:PSS (30 nm)/photoactive layer/LiF (1.5 nm)/Al (100 nm) were fabricated and tested, where the blended solid film of the synthesized small molecules as donor and PC61BM as acceptor was used as the photoactive layer. The

Synthesis and characterization of benzodithiophene and benzotriazole-based polymers for photovoltaic applications

• Desta Gedefaw,
• Marta Tessarolo,
• Margherita Bolognesi,
• Mario Prosa,
• Renee Kroon,
• Wenliu Zhuang,
• Patrik Henriksson,
• Kim Bini,
• Ergang Wang,
• Michele Muccini,
• Mirko Seri and
• Mats R. Andersson

Beilstein J. Org. Chem. 2016, 12, 1629–1637, doi:10.3762/bjoc.12.160

• performance is presumably attributed to the limited solubility of the PTzBDT-1 in organic solvents resulting in enhanced aggregation and poor intermixing with the acceptor material in the active layer. Keywords: alkyl side chains; benzodithiophene; bulk heterojunction solar cells; 2D conjugated polymers

• ; fluorinated benzotriazole; Introduction Over the past decades the research on bulk heterojunction (BHJ) polymer solar cells (PSCs) has been intensified due to the attractive perspectives of producing lightweight and flexible devices via a scalable printing technology at low-cost. The active layer consists of

• also affects the energetic properties of the polymers, resulting in a lower highest occupied molecular orbital (HOMO) for PTzBDT-1 with respect to PTzBDT-2. However, an unexpected behaviour is observed when the two polymers are used as a donor material, in combination with PC61BM as acceptor, in bulk

Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells

• Hideaki Komiyama,
• Chihaya Adachi and
• Takuma Yasuda

Beilstein J. Org. Chem. 2016, 12, 1459–1466, doi:10.3762/bjoc.12.142

• TTA-DPP2 with a fullerene derivative were evaluated by varying the thickness of the bulk heterojunction active layer. As a result of the enhanced visible absorption properties of the star-shaped π-conjugated structure, better photovoltaic performances were obtained with relatively thin active layers

• (40–60 nm). Keywords: bulk heterojunction; diketopyrrolopyrrole; organic solar cells; star-shaped oligomers; tetrathienoanthracene; Introduction Solution-processable organic semiconductors have been intensively studied as key materials for low-cost, flexible, and large-area optoelectronic devices

• , including organic solar cells (OSCs) [1][2][3][4]. OSCs have drawn much attention as promising next-generation renewable energy sources because abundant sun-light energy can be directly converted into electricity. Recently, the power conversion efficiencies (PCEs) of OSCs based on small molecules with bulk

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

• -based copolymers were synthesized, and most of them showed better semiconducting properties in organic field effect transistors (OFETs), bulk-heterojunction (BHJ) solar cells, thermoelectric and electrical memory devices as compared to the counter 3,6-carbazole-based polymers [28][29][30][31][32][33][34

Separation and identification of indene–C₇₀ bisadduct isomers

• Bolong Zhang,
• Jegadesan Subbiah,
• David J. Jones and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2016, 12, 903–911, doi:10.3762/bjoc.12.88

• a number of advantages, such as lightweight flexible devices and low-cost fabrication using roll-to-roll printing [1]. Bulk-heterojunction organic solar cells (BHJ OSC) are a specific type of OSCs which contain a blend of organic electron donor and acceptor materials as the photoactive component

• ]. While high material purity and composition is generally considered an advantage for organic electronic materials, the material criteria for bulk heterojunction organic solar cell applications is less clear. This is owing to the fact that bulk heterojunctions are a mixture of at least two materials (an

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

• interpenetrating network they form within a bulk heterojunction (BHJ), has led to intense research directed towards the synthesis of conjugated polymers for bulk heterojunction organic photovoltaics (OPVs) [1][2][3]. In these devices, the conjugated polymer acts as an electron donor and a soluble fullerene, most

• bulk heterojunction OPVs with moderate power conversion efficiencies. Results and Discussion Synthesis Our synthetic approach was to prepare BODIPY derivatives bearing a brominated thiophene on the meso-position and coupling these derivatives via Suzuki coupling to the central DPP core 8 (Scheme 1

Novel indolin-2-one-substituted methanofullerenes bearing long n-alkyl chains: synthesis and application in bulk-heterojunction solar cells

• Irina P. Romanova,
• Andrei V. Bogdanov,
• Inessa A. Izdelieva,
• Vasily A. Trukhanov,
• Gulnara R. Shaikhutdinova,
• Dmitry G. Yakhvarov,
• Shamil K. Latypov,
• Vladimir F. Mironov,
• Vladimir A. Dyakov,
• Ilya V. Golovnin,
• Dmitry Yu. Paraschuk and
• Oleg G. Sinyashin

Beilstein J. Org. Chem. 2014, 10, 1121–1128, doi:10.3762/bjoc.10.111

• crystalline domains. Moreover, the more soluble AIMs do not show a better miscibility with the P3HT crystalline phase. Keywords: bulk heterojunction; fullerenes; isatin; phosphorus; photovoltaics; Introduction Organic photovoltaics are a rapidly growing field of research due to its potential for production

• /or aromatic ring to achieve the required solubility and miscibility with the donor materials in the bulk heterojunction. Earlier we described the synthesis of IM having methyl- (AIM 1), allyl- (allyl-IM) or aryl- (benzyl-IM) substituents at the nitrogen atom (Figure 1) [7][9]. The first IM-containing

• of long-chain alkyl fragments to the IM nitrogen atom. As a result, the series of novel alkyl-containing indolin-2-one-substituted methanofullerenes (AIMs 2–9) were synthesized. Optical absorption and electrochemical properties of AIMs 1–9 were studied. Bulk heterojunction polymer solar cells based

Controlled synthesis of poly(3-hexylthiophene) in continuous flow

• Helga Seyler,
• Jegadesan Subbiah,
• David J. Jones,
• Andrew B. Holmes and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2013, 9, 1492–1500, doi:10.3762/bjoc.9.170

• of the molecular weight was demonstrated for the first time in flow for conjugated polymers by accurate addition of catalyst to the monomer solution. The P3HT samples synthesized in flow showed comparable performance to commercial P3HT samples in bulk heterojunction solar cell devices. Keywords

• : conjugated polymers; continuous-flow synthesis; controlled polymerization; flow chemistry; organic solar cell materials; Introduction Poly(3-hexylthiophene), P3HT, is the most investigated material in bulk heterojunction (BHJ) organic solar cells (OSC) [1]. The reasons for its dominance in the field include

• catalyst stock solution, afforded lower-molecular-weight polymers (Table 3, entries 2 and 3). In order to assess the device performance of P3HT synthesized using flow methods described in this study, bulk heterojunction (BHJ) solar cells were fabricated and tested. BHJ devices were fabricated with the

Enhancement of efficiency in organic photovoltaic devices containing self-complementary hydrogen-bonding domains

• Rohan J. Kumar,
• Jegadesan Subbiah and
• Andrew B. Holmes

Beilstein J. Org. Chem. 2013, 9, 1102–1110, doi:10.3762/bjoc.9.122

• donor materials in blends with solution-processable fullerenes have produced the highest efficiency organic photovoltaic bulk heterojunction (BHJ) devices to date [13][14]. The critical role of supramolecular interactions together with material behaviour at interfaces has been significant in achieving

• -bonding domain has been incorporated as the electron-deficient moiety in a “push–pull” p-type molecule 2 for organic solar cells. Self-association of this domain could be monitored by 1H NMR, and at higher concentrations the compound was found to form nanostructures and organogels. In bulk heterojunction

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

• Bernd Tieke,
• A. Raman Rabindranath,
• Kai Zhang and
• Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

• , respectively. PPV-type polymers such as P-14 (Table 2) exhibit good solubility in common organic solvents, high thermal stability and a broad UV/visible absorption between 300 and 600 nm in films. Bulk heterojunction solar cells were fabricated and showed a power conversion efficiency of 0.01%. A PPE-type

• polymer such as P-15 (Table 2) exhibited absorption and fluorescence maxima of 510 and 585 nm, respectively, the fluorescence quantum yield being 66%. Polymer/PCBM bulk heterojunction solar cells exhibited a power conversion efficiency of 0.16%. Cao et al. [53] prepared new fluorene-DPP-phenothiazine

• visible exhibiting blue or dark green colours, small band gaps and high charge carrier mobilities. They are suitable as electron donor in bulk heterojunction solar cells with PC60BM or PC70BM as electron acceptors to give maximum power conversion efficiencies of about 5%. In field-effect transistors they

Synthesis of mesogenic phthalocyanine-C₆₀ donor–acceptor dyads designed for molecular heterojunction photovoltaic devices

• Yves Henri Geerts,
• Olivier Debever,
• Claire Amato and
• Sergey Sergeyev

Beilstein J. Org. Chem. 2009, 5, No. 49, doi:10.3762/bjoc.5.49

• transported to the electrodes. Hence, a critical issue in bulk heterojunction PV devices is the control of morphology of materials, in order to provide both the efficient exciton generation and the rapid charge carrier transport. The logical step in the development of this architecture is “molecular

• expect that for such high order of self-organization, liquid crystalline (LC) materials will be beneficial, because they combine order and fluidity, which allows the self-healing of structural defects [8]. One of the most widely used molecules in the bulk heterojunction PV devices is fullerene C60

• dominated by inorganic PV devices, development of organic PV materials is driven by their compatibility with solution processing and hence the potentially low cost of large-scale production by printing technologies [1][2][3]. One of the most popular concepts in the design of organic PV devices is the “bulk

New diarylmethanofullerene derivatives and their properties for organic thin- film solar cells

• Daisuke Sukeguchi,
• Surya Prakash Singh,
• Mamidi Ramesh Reddy,
• Hideyuki Yoshiyama,
• Rakesh A. Afre,
• Yasuhiko Hayashi,
• Hiroki Inukai,
• Tetsuo Soga,
• Shuichi Nakamura,
• Norio Shibata and
• Takeshi Toru

Beilstein J. Org. Chem. 2009, 5, No. 7, doi:10.3762/bjoc.5.7

• heterojunction solar cells; fullerene derivatives; high open-circuit voltage; Introduction Bulk heterojunction photovoltaic cells consisting of thin-film composites of conjugated polymers (donors) and fullerene derivatives (acceptors) are promising candidates for inexpensive, renewable solar energy conversion

• acceptor [7][8][9][10]. Using a combination of these donor and acceptor molecules together with the optimized solvent processing, composition, and effect of device annealing, PCE has reached up to 5% [11][12][13][14][15][16][17]. In addition to PCBM widely studied as the bulk heterojunction (BHJ) acceptor

• highly dependent on the solvent used [23][24]. Recently, we briefly communicated a soluble bulk-heterojunction organic photovoltaic P3HT device using a newly synthesized methanofullerene derivative 1a [25]. In this paper, we give a full account of our studies on new bulk-heterojunction (BHJ) devices