Quantitatively Analyzing the Influence of Side Chains on Photovoltaic Properties of Polymer−Fullerene Solar Cells

Using single-bonded and fused aromatic rings are two methods for extending the π-conjugation in the vertical direction of benzo [1,2-b:4,5-b′] dithiophene (BDT) unit. To investigate which method is more efficient in nonfullerene systems, two novel polymers based on alkylthionaphthyl and alkylthiobiphenyl substituted BDT named PBDTNS-FTAZ and PBDTBPS-FTAZ are designed and synthesized. Two polymers only exhibit small differences in structure, but huge differences in photovoltaic properties. They are studied by blended with 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)indanone)-5,5,11,11-tetrakis(4-hexylphenyl)dithieno [2,3-d’:2,3’-d’]-s-indaceno [1,2-b:5,6-b’] dithiophene (ITIC). The device based on PBDTNS-FTAZ:ITIC showed the best power conversion efficiency (PCE) of 9.63% with the Voc of 0.87 V, a Jsc of 18.06 mA/cm2 and a fill factor of 61.21%, while the PBDTBPS-FTAZ:ITIC only exhibit a maximum PCE of 7.79% with a Voc of 0.86 V, a Jsc of 16.24 mA/cm2 and a relatively low fill factor of 55.92%. Therefore, extending π-conjugation with alkylthionaphthyl is more effective against constructing nonfullerene solar cells.

Download Full-text

Synthesis and photovoltaic properties of two-dimensional benzodithiophene-thiophene copolymers with pendent rational naphtho[1,2-c:5,6-c]bis[1,2,5]thiadiazole side chains

Journal of Materials Chemistry A ◽

10.1039/c5ta07205k ◽

2015 ◽

Vol 3 (46) ◽

pp. 23149-23161 ◽

Cited By ~ 27

Author(s):

Xiaopeng Xu ◽

Kui Feng ◽

Kai Li ◽

Qiang Peng

Keyword(s):

Solar Cells ◽

High Performance ◽

Molecular Design ◽

Polymer Solar Cells ◽

Side Chains ◽

Two Dimensional ◽

Photovoltaic Properties ◽

Solvent Vapour ◽

Rational Molecular Design ◽

Annealing Method

Rational molecular design of the conjugated side chains and the solvent vapour annealing method were employed in this work to develop high performance two-dimensional copolymer donors and their efficient polymer solar cells.

Download Full-text

Synthesis and photovoltaic properties of an n-type two-dimension-conjugated polymer based on perylene diimide and benzodithiophene with thiophene conjugated side chains

Journal of Materials Chemistry A ◽

10.1039/c5ta05014f ◽

2015 ◽

Vol 3 (36) ◽

pp. 18442-18449 ◽

Cited By ~ 57

Author(s):

Youdi Zhang ◽

Qun Wan ◽

Xia Guo ◽

Wanbin Li ◽

Bing Guo ◽

...

Keyword(s):

Solar Cells ◽

Conjugated Polymer ◽

Polymer Solar Cells ◽

Perylene Diimide ◽

Side Chains ◽

Two Dimensional ◽

Stille Coupling ◽

Photovoltaic Properties ◽

Two Dimension

A novel n-type two-dimensional (2D) conjugated polymer based on bithienyl-benzodithiophene (BDT) and perylene diimide (PDI), P(PDI-BDT-T), is synthesized by Stille coupling for applications in all-polymer solar cells (PSCs).

Download Full-text

Efficient Solar Cells Based on a Polymer Donor with β-Branching in Trialkylsilyl Side Chains

Organic Materials ◽

10.1055/s-0041-1726427 ◽

2021 ◽

Vol 03 (02) ◽

pp. 134-140

Author(s):

Haijun Bin ◽

Martijn M. Wienk ◽

René A. J. Janssen

Keyword(s):

Solar Cells ◽

Organic Solar Cells ◽

Short Circuit ◽

Energy Levels ◽

Short Circuit Current ◽

Open Circuit ◽

Side Chains ◽

Photovoltaic Properties ◽

Alkyl Groups ◽

High Efficient

Side-chain engineering is an important strategy in designing novel polymer semiconductor materials for high-efficient organic solar cells. The use of trialkylsilyl side chains can improve the photovoltaic efficiency by decreasing the energy of the HOMO of the polymer and improving its crystallinity and hole mobility. Compared to simple linear derivatives, α-branching in the alkyl groups of trialkylsilyl side chains causes strong aggregation and excessive phase separation in the photoactive layer, leading to poor device performance. β-Branching of the alkyl groups has not yet been used in trialkylsilyl side chains. Herein, we describe a new polymer (J77) with triisobutylsilyl side chains to investigate the effect of β-branching on the molecular aggregation, optical properties, energy levels, and photovoltaic properties. We find that compared to α-branching, β-branching of alkyl groups in trialkylsilyl side chains significantly reduces aggregation. This enables J77 to form blend morphologies in films that provide high-efficient solar cells in combination with different non-fullerene acceptors. Moreover β-branching of the alkyl groups in trialkylsilyl side chains lowers the HOMO energy level of J77 and increases the open-circuit voltage of J77-based solar cells without sacrificing short-circuit current density or fill factor.

Download Full-text

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

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.12.160 ◽

2016 ◽

Vol 12 ◽

pp. 1629-1637 ◽

Cited By ~ 16

Author(s):

Desta Gedefaw ◽

Marta Tessarolo ◽

Margherita Bolognesi ◽

Mario Prosa ◽

Renee Kroon ◽

...

Keyword(s):

Solar Cells ◽

Bulk Heterojunction ◽

Coupling Reaction ◽

Side Chains ◽

Photovoltaic Properties ◽

Polymer Backbone ◽

Heterojunction Solar Cells ◽

Highest Occupied Molecular Orbital ◽

Alkyl Side Chains

Two high bandgap benzodithiophene–benzotriazole-based polymers were synthesized via palladium-catalysed Stille coupling reaction. In order to compare the effect of the side chains on the opto-electronic and photovoltaic properties of the resulting polymers, the benzodithiophene monomers were substituted with either octylthienyl (PTzBDT-1) or dihexylthienyl (PTzBDT-2) as side groups, while the benzotriazole unit was maintained unaltered. The optical characterization, both in solution and thin-film, indicated that PTzBDT-1 has a red-shifted optical absorption compared to PTzBDT-2, likely due to a more planar conformation of the polymer backbone promoted by the lower content of alkyl side chains. The different aggregation in the solid state 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 heterojunction solar cells. Even though PTzBDT-1 showed favourable optical and electrochemical properties, the devices based on this polymer present a power conversion efficiency of 3.3%, considerably lower than the efficiency of 4.7% obtained for the analogous solar cells based on PTzBDT-2. The lower 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.

Download Full-text

Charge Transfer Dynamics and Photovoltaic Properties of Perovskite Solar Cells: Effects of the Energy Level Alignment of Zn1-xMgxO Electron Selective Layer

10.29363/nanoge.ap-hopv.2018.057 ◽

2017 ◽

Author(s):

Qing Shen ◽

Chao Ding ◽

Yaohong Zhang ◽

Feng Liu ◽

Shuichiro Fujino ◽

...

Keyword(s):

Solar Cells ◽

Charge Transfer ◽

Energy Level ◽

Perovskite Solar Cells ◽

Photovoltaic Properties ◽

Selective Layer ◽

Energy Level Alignment ◽

Charge Transfer Dynamics

Download Full-text

A polymeric bis(di-p-anisylamino)fluorene hole-transport material for stable n-i-p perovskite solar cells

New Journal of Chemistry ◽

10.1039/d0nj04157b ◽

2021 ◽

Author(s):

Marie-Hélène Tremblay ◽

Kelly Schutt ◽

Yadong Zhang ◽

Stephen Barlow ◽

Henry J. Snaith ◽

...

Keyword(s):

Solar Cells ◽

Perovskite Solar Cells ◽

Heat Stability ◽

Hole Transport ◽

Side Chains ◽

Hole Transporting

Half-devices made with a norbornene homopolymer with hole-transporting 2,7-bis(di-p-anisylamino)fluorene side chains exhibit improved light and heat stability in comparison to those incorporating spiro-OMeTAD.

Download Full-text