Naphthalenothiophene Imide-Based Polymer Donor for High-Performance Polymer Solar Cells

Abstract

Naphthalenothiophene imide (NTI), bearing six-membered imide and a five-membered aromatic ring, was synthesized by a one-step Suzuki reaction in high yield. NTI is an electron-deficient monomer that could effectively lower the HOMO energy level of the polymer. Thus, the NTI-based polymer PNTB1 has a low-lying HOMO energy level (−5.42 eV) without introducing any F or Cl group into the polymer backbone. By mixing with a nonfullerene electron acceptor Y6, solar cell devices exhibit power conversion efficiency as high as 15.18%. Because of the high efficiency of the NTI-based polymer and avoidance of multi-step synthesis of introducing other electron-accepting groups into the polymer chain, the electron-deficient NTI is a promising building unit for high-performance polymer donors.

Modulating Chlorination Position on Polymer Donors for Highly Efficient Nonfullerene Organic Solar Cells

“…Moreover, the properties can be well controlled by changing the D or A units to tune the internal electron pushÀpull effects. [11,12] In particular, we also note that many outstanding DÀA polymer donors, such as PBDB-T, PM6, PM7, etc., are based on benzodithiophene (BDT) as D unit and 1,3-bis(thiophen-2-yl)-5,7-bis(2-ethylhexyl) benzo-[1,2-c:4,5-c'] dithiophene-4,8-dione (BDD) as A unit [13][14][15] Further, the properties can also be modulated through the substituents attached at the conjugated backbone. Introducing an electron-withdrawing substituent into the polymer has been demonstrated as an effective method.…”

Wide-bandgap polymer donors for non-fullerene organic solar cells

“…76 In 2021, Wu et al reported a pentacyclic acceptor unit naphthalene-thiophene imide (NTI) and developed a series of D–A copolymers with low HOMO energy levels due to the electron-deficient imide group and aromatic five-membered ring of NTI. 77 For example, PNTB6-Cl based on chlorinated BDTT and NTI with a linear hexyl chain showed poor solubility in chloroform due to its stronger intermolecular interactions and shorter π–π stacking distance. Consequently, the layer-by-layer (LBL) processed OSCs based on PNTB6-Cl :N3 exhibited an impressive PCE of 17.59% with excellent batch-to-batch reproducibility.…”

An over 16% efficiency organic solar cell enabled by a low-cost pyrazine-based polymer donor

“…[10][11][12] Meanwhile, the complex aromatic cyclization or uorination reactions of the above-mentioned materials with state-of-the-art PCEs, such as uorinated 2D-conjugated benzo[1,2-b:4,5-b ′ ]dithiophene (BDT) 8 and alkylthiophene linked DTBT, 13 may thereby obstruct their future commercialization due to the cost issue. To reduce the synthetic cost, some efforts have been made to shorten synthesis steps, 14,15 employ simplied building block units, [16][17][18] or control reaction conditions and simplify purication methods, 19 among which designing novel photovoltaic materials with non-fused-ring chemical structures and without any expensive functional groups has been considered as an effective way to solve the critical cost issue.…”