A planar electron acceptor for efficient polymer solar cells

Macromol. Rapid Commun.

Hou

et al. 2017

Recently, research on nonfullerene acceptors in organic solar cells has gradually become a hot topic due to such superior characteristics of light absorption and energy-level-convenient manipulation, multiformity of the photoactive material structures, as well as the extensive area in production compared to the fullerene derivatives. However, the nonfullerene acceptors evolved slowly before 2012 and, as a matter of fact, the power conversion efficiency values could only bear 2.0%. Strikingly, nonfullerene acceptors have developed at a fast pace since 2013, with the best device performance of 13.1% now. In this review, recent research progress on nonfullerene acceptors, including small molecules and polymers, are sorted and summarized on the basis of the different characteristics.

Section: Nonfullerene Small Molecule Acceptorsmentioning

confidence: 99%

Recent Advances in Nonfullerene Acceptors for Organic Solar Cells

Macromol. Rapid Commun.

Hou

et al. 2017

“…[1][2][3][4][5][6] However, further development of OSCs would require more efficient and low-cost materials. [9][10][11][12] OSCs using non-fullerene acceptors, including small molecule acceptors [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] and polymer acceptors, 30 have achieved power conversion efficiencies (PCEs) of 5-11%. 7,8 Developing new electron acceptors has become an important topic.…”

Section: Introductionmentioning

confidence: 99%

A simple perylene diimide derivative with a highly twisted geometry as an electron acceptor for efficient organic solar cells

et al. 2016

J. Mater. Chem. A

109

† Electronic Supplementary Information (ESI) available: Instrument, materials, density functional theory calculation details, 1 H NMR spectra of B(PDI)3 solution in CDCl3, TGA and DSC curves of B(PDI)3, J 0.5 -V curves of the hole-only and electrononly devices based on PTB7-Th:B(PDI)3 films, and AFM images. SeePerylene diimide (PDI), which features with intense absorption, low-lying energy level, and high electron mobility, is a promising building block for electron acceptors in organic solar cells (OSCs). However, this planar molecule has strong tendency to form large aggreates during film formation that strongly limits its OSC performance. Herein, we report a new and simple PDI derivative, B(PDI)3, in which a central benzene unit is employed to connect with three PDI arms. This compact arrangment of sterically bulky PDI moieties leads to a twisted molecular geometry of the reseultant structure. It suppresses the strong crystallization tendency of PDI chromophores, owing to the broken molecular coplanarity and symmetry . Thereby, B(PDI)3 is applied as the non-fullerene acceptor in OSCs, providing a good power conversion efficiency of 5.65% when blended with PTB7-Th donor.

“…Theoretically, semicrystalline conjugated polymers can be synthesized with the following characteristics: (a) polymers with high regioregularity, (b) polymers with high polarity functional groups, (c) polymers with long alkyl side chains that will cause side‐chain crystallinity, and (d) high planarity backbone with strong π–π interaction . Researchers have found improved carrier mobility for crystallizable semiconducting polymer such as P3HT.…”

Section: Introductionmentioning

confidence: 99%

A molecular structure and crystallization correlation study of pyromellitic diimide‐based conjugated copolymers

Tsai

Huang

2018

J Chinese Chemical Soc

Three pyromellitic diimide(PMDI)‐based polymers—poly(pyromellitic diimide‐co‐bithiophene) [poly(PMDI‐BTh)], poly(pyromellitic diimide‐co‐tetrathiophene) [poly(PMDI‐TTh)], and poly(pyromellitic diimide‐co‐benzodithio‐ phene) [poly(PMDI‐BDTTh)]—are synthesized to study the influence of different thiophene‐containing electron‐donating groups on the crystallizability of PMDI‐based conjugated polymers. Computer simulation using Density Functional Theory (DFT) [Gaussian B3LYP/6–31 + G(d,p)] indicates that poly(PMDI‐BDTTh) has a more planar molecular structure than the other two copolymers. Powder XRD diffraction experiment of the poly(PMDI‐BDTTh) shows a diffraction peak at about 2θ = 6.0°, but no diffraction peak occurs for poly(PMDI‐BTh) and poly(PMDI‐TTh). Although PMDI is a planar structure that is favorable for the molecular aggregation, a comonomer with planar structure seems to be very crucial in order to synthesize a crystallizable push–pull‐type PMDI‐based conjugated copolymer.