Halogen-Free Wide Band Gap Polymer Donors Based on Dicyanobithiophene for Efficient Organic Solar Cells.

Conjugated polymer donors have always been one of the important components of organic solar cells (OSCs), particularly those featuring simple synthetic routes, proper energy levels, and appropriate aggregation behavior. In this work, we employed a nonfused electron-deficient building block, dicyanobithiophene (2CT), for constructing high-performance donors. Combining this with side-chain engineering, two novel halogen-free polymer donors, PB2CT-BO and PB2CT-HD, were reported.

Revealing the Molecular Weight Effect on Highly Efficient Polythiophene Solar Cells.

Polythiophenes (PTs) are promising electron donors in organic solar cells (OSCs) due to their simple structures and excellent synthetic scalability. Benefiting from the rational molecular design, the power conversion efficiency (PCE) of PT solar cells has been greatly improved. Herein, five batches of the champion PT (P5TCN-F25) with molecular weights ranging from 30 to 87 kg mol were prepared, and the effect of the molecular weight on the blend film morphology and photovoltaic performance of PT solar cells was systematically investigated.

An electron acceptor featuring a B-N covalent bond and small singlet-triplet gap for organic solar cells.

BNTT2F, an electron acceptor featuring a B-N covalent bond and singlet-triplet gap as low as 0.20 eV the multiple resonance effect, is developed for organic solar cells. The optimized device based on BNTT2F offered an efficiency of 8.

A Facile Synthesized Polymer Featuring B-N Covalent Bond and Small Singlet-Triplet Gap for High-Performance Organic Solar Cells.

High-efficiency organic solar cells (OSCs) largely rely on polymer donors. Herein, we report a new building block BNT and a relevant polymer PBNT-BDD featuring B-N covalent bond for application in OSCs. The BNT unit is synthesized in only 3 steps, leading to the facile synthesis of PBNT-BDD.

Rational Design of Low Band Gap Polymers for Efficient Solar Cells with High Open-Circuit Voltage: The Profound Effect of Me and Cl Substituents with a Similar van Der Waals Radius.

Generally, low band gap material-based photovoltaic devices have reduced open circuit voltage (), and realizing the trade-off between the low band gap ( < 1.6 eV) and high (>0.9 V) could be critical to give efficient polymer solar cells, especially for high-performance semitransparent PSCs and tandem solar cells.

Chlorinated Polymers for Efficient Solar Cells with High Open Circuit Voltage: The Influence of Different Thiazole Numbers.

The chlorination strategy has gradually become a promising approach to improve the open circuit voltage (V ) in polymer solar cells. In this work, by using an efficient thiazole-induced strategy in a polymer backbone, three thieno[3,4-b]thiophene (TT)-based polymers-PBClTTz-0, PBClTTz-1, and PBClTTz-2-are designed and synthesized with a Cl-substituted benzodithiophene (BDT) moiety and a thiazole unit as a π spacer. As expected, all of the polymers show a desirable open circuit voltage (V ) of >0.