Isoindigo-based copolymers for polymer solar cells with efficiency over 7%

Abstract

A series of isoindigo-based low-band-gap copolymers (PnTI) containing an extended thiophene unit in the donor segment of the polymer were synthesized. The results show that the extended thiophene unit with centrosymmetric conformation simultaneously broadens the polymer absorption and enhances the crystallinity and, thus, hole mobility. Consequently, with additional improved solubility, the polymer P6TI exhibits the highest PCE of 7.25% (and a high J sc of 16.24 mA cm À2 ) among isoindigo-based low-bandgap copolymers. This work demonstrates that by simply adjusting the donor segment and with relatively simple synthetic schemes, a material for high-performance and scalable PSCs will become available.

Recent Advances in Isoindigo‐Inspired Organic Semiconductors

“…The fill factor also increased slightly, from 0.63 to 0.69, helping to offset the decrease in V oc from 0.89 to 0.70 V. The good performance of 4 : PC 71 BM devices was an important milestone for isoindigo‐based polymers, and prompted further isoindigo‐oligothiophene copolymer research. Copolymers of isoindigo and oligothiophenes (e. g., 5 and 6 ) would go on to become some of the most popular isoindigo‐based polymer semiconductors owing to their ease of synthesis, excellent optoelectronic properties, and OPV performance …”

An Electron‐Deficient Small Molecule Accessible from Sustainable Synthesis and Building Blocks for Use as a Fullerene Alternative in Organic Photovoltaics

“…Inherentt o each is as trong electron-withdrawing character,r elatively narrow band gaps and planar structures. [35,38,40,41,45,[49][50][51][52][53][54] Most importantly,i soindigo is proven to be more easily accessible via as traightforward synthetic procedure from readily available startingm aterials and is intrinsically more soluble than DPP. [55] Isoindigo is composed of two symmetrical oxindole rings that are through conjugated at the 3-carbon by as ite of unsaturation; this effectively binds the two electron-withdrawing carbonyls and two electron-rich phenyl rings in a trans-conformation.…”

“…[1,32,33] With these concerns in mind, am aterial was designed based on an isoindigo (II)m olecular core with terminal phthalimide (Phth)e nd cap units.I soindigo is an aturallyo ccurring isomer of the largest singlet extile dye in the world, indigo, [34] that is found in the leaves of Isatis tinctoria. [35,[37][38][39][40][41] Phthalimide, and its precursor material phthalic anhydride are commercially availablea tl ow cost. [35,[37][38][39][40][41] Phthalimide, and its precursor material phthalic anhydride are commercially availablea tl ow cost.…”

“…[35,36] Isoindigo can be effectively synthesized in bulk quantities, allowing the preparation of numerousi soindigo-based donorm aterials with promising performance in organic electronics. [35,[37][38][39][40][41] Phthalimide, and its precursor material phthalic anhydride are commercially availablea tl ow cost. Phthalic anhydride derivatives are common plasticizers anda re widely availablef rom the xylenes feedstock, while phthalimide is produced almoste xclusively from phthalic anhydride and ammonia and constitutes an important intermediate in the production of agricultural pesti-An electron-deficient small molecule accessible from sustainable isoindigo and phthalimide building blocks was synthesized via optimized synthetic procedures that incorporate microwave-assisted synthesis and ah eterogeneousc atalystf or Suzuki coupling, and direct heteroarylation carbon-carbon bond forming reactions.…”

Influence of Physical Load on the Stability of Organic Solar Cells with Polymer : Fullerene Bulk Heterojunction Nanolayers

“…Of various organic solar cells, polymer:fullerene solar cells have been extensively studied because of high power conversion efficiency (PCE) approaching ~12% via gradual advances in light-absorbing semiconducting polymers and fullerene derivatives [7][8][9][10][11][12][13] . In addition, polymer:fullerene solar cells can be manufactured by employing various wet-coating/printing technologies with continuous roll-to-roll processes at low temperatures, which may enable custom-designed plastic solar modules leading to wide spreading of solar cells in our daily life 3) .…”