An alternating copolymer, poly(2-(5-(5,6-bis(octyloxy)-4-(thiophen-2-yl)benzo[c][1,2,5]thiadiazol-7-yl)thiophen-2-yl)-9-octyl-9H-carbazole) (HXS-1), was designed, synthesized, and used as the donor material for high efficiency polymer solar cells. The close packing of the polymer chains in the solid state was confirmed by XRD. A J(sc) of 9.6 mA/cm(2), a V(oc) of 0.81 V, an FF of 0.69, and a PCE of 5.4% were achieved with HXS-1 and [6,6]-phenyl C(71)-butyric acid methyl ester (PC(71)BM) as a bulk heterojunction active layer spin-coated from a solvent mixture of 1,2-dichlorobenzene and 1,8-diodooctane (97.5:2.5) under air mass 1.5 global (AM 1.5 G) irradiation of 100 mW/cm(2).

We have developed a kind of novel fused-ring small molecular acceptor, whose planar conformation can be locked by intramolecular noncovalent interaction. The formation of planar supramolecular fused-ring structure by conformation locking can effectively broaden its absorption spectrum, enhance the electron mobility, and reduce the nonradiative energy loss. Polymer solar cells (PSCs) based on this acceptor afforded a power conversion efficiency (PCE) of 9.6%. In contrast, PSCs based on similar acceptor, which cannot form a flat conformation, only gave a PCE of 2.3%. Such design strategy, which can make the synthesis of small molecular acceptor much easier, will be promising in developing a new acceptor for high efficiency polymer solar cells.

The thermochromic and mechanochromic fluorescence of diphenyldibenzofulvenes is investigated. Emission is boosted and blue‐shifted upon crystallization. Yellow emissive crystals of the material transform to green fluorescent crystals upon heating before melting. Reversible switching of the emission color and efficiency are achieved by repeated amorphization and crystallization of dye molecules by a pure thermal process or grinding–heating cycles.

Non-fullerene fused-ring electron acceptors boost the power conversion efficiency of organic solar cells, but they suffer from high synthetic cost and low yield. Here, we show a series of low-cost noncovalently fused-ring electron acceptors, which consist of a ladder-like core locked by noncovalent sulfur–oxygen interactions and flanked by two dicyanoindanone electron-withdrawing groups. Compared with that of similar but unfused acceptor, the presence of ladder-like structure markedly broadens the absorption to the near-infrared region. In addition, the use of intramolecular noncovalent interactions avoids the tedious synthesis of covalently fused-ring structures and markedly lowers the synthetic cost. The optimized solar cells displayed an outstanding efficiency of 13.24%. More importantly, solar cells based on these acceptors demonstrate very low non-radiative energy losses. This research demonstrates that low-cost noncovalently fused-ring electron acceptors are promising to achieve high-efficiency organic solar cells.

Five polymer donors with distinct chemical structures and different electronic properties are surveyed in a planar and narrow-bandgap fused-ring electron acceptor (IDIC)-based organic solar cells, which exhibit power conversion efficiencies of up to 11%.

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A ternary-blend strategy is presented to surmount the shortcomings of both fullerene derivatives and nonfullerene small molecules as acceptors for the first time. The optimal ternary device shows a high power conversion efficiency (PCE) of 10.4%. Moreover, a significant enhancement in PCE (≈35%) relative to both of the binary reference devices, which has never been achieved before in high-efficiency ternary devices, is demonstrated.

This article divides the synthetic routes leading to dendronized polymers into two main categories (attach‐to and macromonomer) and compares their respective advantages and disadvantages. It gives a comprehensive overview on the kind of structures presently available and also spans the bridge between both polymers and molecular objects, decorated with only a few dendrons, and the structurally related, but less well defined polymers with hyperbranched side chains.