This paper presents recent advances in green-solvent-processable all-PSCs from the material design and morphological control perspective. And further reviews progress in using more environmentally friendly solvents (i.e., water or alcohol) to achieve genuinely sustainable and environmentally friendly manufacturing all-PSCs.

This paper presents recent advances in green-solvent-processable all-PSCs from the material design and morphological control perspective. And further reviews progress in using more environmentally friendly solvents (i.e., water or alcohol) to achieve genuinely sustainable and environmentally friendly manufacturing all-PSCs.

Machine learning is a powerful tool that can guide the experimentalists to discover and develop new high-performance polymeric materials. In this mini-review, various case studies related to the use of machine learning for polymer solar cells research are discussed. Various challenges and opportunities are also discussed.

We synthesized a new PA PYT-Tz with fused-ring benzotriazole (BTz)-based A’-DAD-A’ structure as electron-deficient-core, n-nonane as alkyl-side-chain and thiophene as π-bridge. PYT-Tz showed significantly red-shifted absorption and up-shifted LUMO level compared with PYT due to the less electron-deficient property of BTz unit, leading to a high PCE of 15.10%.

Thiophene π-bridge alkyl substitution demonstrated an important strategy to enhance the photovoltaic performance of the polymer solar cells. Benefit from a good balance of solubility and molecular planarity, the n-hexyl substituted polymer donor PBP-C6 based devices, with Y5 as acceptor, exhibited the highest power conversion efficiency up to 11.60% among three donor polymers.

Double-cable conjugated polymers with fullerene pendant were synthesized via “functionalization-polymerization” method. The power conversion efficiencies (PCEs) based on these polymers increased from 0.71% to 1.71% with the enhanced fullerene contents.

A set of halogen-free polymers (PBCNT25, PBCNT50, and PBCNT75) based on 3,4-dicyanothiophene (DCT) have been constructed via ternary random copolymerization for high-performance polymer solar cells (PSCs). A remarkable efficiency of 15.7% has been achieved in PBCNT75:Y6-BO blend, which is one of the best results achieved by halogen-free polymers.

Four narrow-bandgap fused-ring electron acceptor materials named as nTTIC (n = 2, 3, 4, and 5) with strong near-infrared absorption are synthesized and the effects of thieno[3,2-b]thiophene number on their photovoltaic performance are systematically studied. 3TTIC yields the best performance, while 5TTIC shows the lowest efficiency.

A novel two-dimensional A-D-A acceptor named as CH8 with four electron-withdrawing end units has an extremely low electron reorganization energy of 98 meV. When blended with PM6, a considerate PCE of 9.37%, along with a high Voc 0.889 V and low Eloss below 0.6 eV is achieved.

Two lowly fused NFAs were developed by tailoring the fused 7-ring central core of Y6 into a lowly fused 5-ring with two octyloxythiophene bridges to form the isomeric structures and tune the overall properties, which improved the PCE form 0.97% of BTP-in-4F based devices to 13.32% of BTP-out-4F based devices.

The polymer donor containing specific groups, such as carbonyl group and fluorine atom, can form hydrogen bond with triethanolamine, which can enlarge the negative electrostatic potential of the oxygen atoms on the hydroxyl group and enhance the passivation effect on the oxygen vacancies of the metal oxides, thus improving the performance of organic solar cells.

Fully non-fused ring acceptors (NFRAs), p-PTIC4Cl and t-PTIC4Cl, are developed via a concise synthetic route. It is revealed that the tuning of unaxisymmetric aromatic chains could modulate the self-assemble properties of NFRAs, hence optimizing their optoelectronic properties to construct the cost-effective polymer solar cells.

A PM6/Y6 bilayer model was employed to investigate the long-range alignment of molecular packing induced photoelectric conversion process. The smaller energy loss and longer charge carrier lifetime can be observed in bilayer devices with aligned Y6 molecules, which contribute to the higher power conversion efficiency than the as-cast devices.

Three polymerized small molecule acceptors with nonfused-core are designed to simplify the synthetic procedures. Relative to the fused-ring based counterparts, these three polymer acceptors exhibit much higher figure-of-merit value. Encouragingly, a power-conversion efficiency of 8.80% is achieved in the PBTI-Cl-based all-polymer solar cells.

A vinyl-bridged polymerized small-molecule acceptor PSV featuring planar conjugated backbone is designed and synthesized. PSV film exhibits favorable intermolecular packing and a high electron mobility of 0.54 cm² V⁻¹ s⁻¹ was achieved. Such superior optoelectronic properties endow PM6:PSV-based APSCs with high PCEs of 15.73% and 13.3% at thin and thick film, respectively.

We designed and synthesized a new acceptor called DTz-R1 via suppressing the energetic disorder. The 100 cm² organic photovoltaic cell gives an impressive efficiency of 23.0% under indoor light illumination. Our results demonstrate that modulation of the energetic disorder can be a feasible molecular design strategy.

An alternating copolymer containing B←N units with low-lying energy levels and narrow bandgap is developed for all-polymer solar cells (all-PSCs). The all-PSC device using this polymer as an electron acceptor exhibits the power conversion efficiency of 15.09% and potential for large-scale preparation.

The BDT based regio-regular polymer reg-PTF and the corresponding random polymer ran-PTF are developed as donor materials. Acceptors with different energy level are severally match with the two polymers can give the significant different PCE due to the different energy level offset between the donor and acceptor materials.