Themed collection Celebrating Prof. Fred Wudl’s 80th Birthday

Qichun Zhang, Dmitrii F. Perepichka, Hong Meng and Yongsheng Chen introduce the Materials Chemistry Frontiers themed issue celebrating Professor Fred Wudl's 80th birthday.

This review summarizes recent progress on chemistry and engineering techniques of organic polymers across a range of electrically insulating polymers, semiconducting polymers and conducting polymers for neural interfacing, stimulation and recording.

Synthetic chemistry towards two-dimensional semiconducting polymers (2DSPs) with planar π-conjugated structures is reviewed and their unique chemical and physical properties derived from the extended π-conjugation are discussed.

Radicals, organic molecules with unpaired electrons, are applied across different scientific disciplines such as electronics, energy storage and biochemistry.

In this review, we focus on the recent advances in organic solar cells enabled by A–DA′D–A type acceptors and summarize the correlation between molecular structure, molecular packings, optoelectronic properties, and photovoltaic performance.

This review gives an overview of strategies to tailor organic semiconductors with designed physical structures and chemical functionalities for development of chemical and biological sensors based on organic field effect transistors.

A timely review of recent exciting progress is provided regarding the molecular design, optical characterization, and device fabrications of novel 2D halide perovskite materials incorporating functional organic semiconducting building blocks.

In this review, we will focus on the recent progress in the synthetic strategies, photo-electronic properties, molecular packing modes and applications of azaacenes (n ≥ 6) with single-crystal structures.

Nanoscopic macrocycles could have unusual magnetic, optical, and electronic properties when compared to their linear counterparts.

Effects of purification were studied in organic field effect transistors. The results presented here indicate that the purity of organic semiconductors is a key parameter to achieve high performance for the field of organic field effect transistors.

The mixed-valence (Sm_1/3Ca_2/3)_2.75C₆₀ fulleride undergoes an abrupt strongly hysteretic reversible phase transition accompanied by a drastic increase in the bulk Sm valence by ∼20% to +2.71 through the application of external pressure.

Hydrogen bonding of diindolopyrrole donors with quinone acceptors enhances the orbital interactions and modulates the band gap and electrical properties of their complexes.

A set of oligofluorene-type pendant conjugated molecules based on heterogeneous core structures (C1 and C2) with enhanced morphological and emissive properties have been synthesized and explored as gain media for organic semiconductor lasers.

Conjugated polyelectrolytes (CPEs) are a promising class of materials for photovoltaic and sensing applications due to their ability to undergo efficient photoinduced electron transfer (ET).

This work reports on the preparation of carbon dots (CDs) and rylene diimide hybrids and their spectroscopic investigation reveals complex inter-chromophoric interactions.

Spiro-OMeTAD can be doped by infiltration of F₄TCNQ from the vapor phase without causing crystallization. Optical spectroscopy and thermopower measurements examined the question of the formation of dication states by charge transfer doping.

The electronic, optical, vibrational, and charge-transport properties of a series of benzothienobenzothiophene–TCNQ co-crystals are discussed on the basis of density functional theory calculations.

This work shows that trifluoromethyl (CF₃) substituents can be used to increase the rate of thermally activated delayed fluorescence (TADF) in conjugated organic molecules by tuning the excitonic character of the singlet and triplet excited states.

A new family of n-type dopants for organic semiconductors is reported. Changing the alkyl chain of these triazabicyclodecene (TBD) dopants alters their physical properties, including thermal stability, and influences their doping efficiency.

A new acceptor–donor–acceptor (A–D–A) small molecule acceptor, named FCO-2F, is designed and synthesized based on the previous acceptor F-H.

Conjugated polyions (CPIs) offer synthetic tunability and selective processing into insulating, semiconducting and metallic states simply by controlling acidity.

Two fluoro-alkyl substituted isothianaphthene bisimide materials with high solubility and their applications in stable n-type OTFTs are demonstrated.

Two n-type pyridine and selenophene-containing polymers were synthesized and the structure–property relationships were investigated, followed by polarity switching from ambipolarity to unipolar characteristics via the doping method.

In-depth understanding of the doped and de-doped states of CPE-K, a unique, water-soluble, highly conductive polymer.

A liquid crystal molecule with versatile properties, like the indicators of a clock, shows various applications.

3D polycyclic aromatic hydrocarbons are synthesized, and their applications for organic field-effect transistors and organic light-emitting diodes are explored.