Solution-Processable High-Quality Graphene for Organic Solar Cells

The unique optical and electronic properties of graphene open up new opportunities for optoelectronics. This work reports the use of <i>solution-processed</i> high-quality graphene as transparent conductive electrode in an organic solar cell using an electrochemical approach. The fabricated thieno­[3,4-<i>b</i>]­thiophene/benzo­dithiophene:phenyl-C₇₁-butyric acid methyl ester (PTB7:PCB₇₁M) bulk heterojunction organic solar cell based on the exfoliated graphene (EG) anode exhibits a power conversion efficiency of 4.23%, making EG promising for next-generation flexible optoelectronic devices

Tuning the Piezoresistive Behavior of Graphene-Polybenzoxazine Nanocomposites: Toward High-Performance Materials for Pressure Sensing Applications

Flexible piezoresistive pressure sensors are key components in wearable technologies for health monitoring, digital healthcare, human–machine interfaces, and robotics. Among active materials for pressure sensing, graphene-based materials are extremely promising because of their outstanding physical characteristics. Currently, a key challenge in pressure sensing is the sensitivity enhancement through the fine tuning of the active material’s electro-mechanical properties. Here, we describe a novel versatile approach to modulating the sensitivity of graphene-based piezoresistive pressure sensors by combining chemically reduced graphene oxide (rGO) with a thermally responsive material, namely, a novel trifunctional polybenzoxazine thermoset precursor based on tris(3-aminopropyl)amine and phenol reagents (PtPA). The integration of rGO in a polybenzoxazine thermoresist matrix results in an electrically conductive nanocomposite where the thermally triggered resist’s polymerization modulates the active material rigidity and consequently the piezoresistive response to pressure. Pressure sensors comprising the rGO-PtPA blend exhibit sensitivities ranging from 10–2 to 1 kPa–1, which can be modulated by controlling the rGO:PtPA ratio or the curing temperature. Our rGO-PtPA blend represents a proof-of-concept graphene-based nanocomposite with on-demand piezoresistive behavior. Combined with solution processability and a thermal curing process compatible with large-area coatings technologies on flexible supports, this method holds great potential for applications in pressure sensing for health monitoring

Donor–Acceptor Conjugated Polymers for Single-Component Near-Infrared II Organic Phototransistors with Ultrahigh Photoresponsivity

The design of donor–acceptor (D–A) conjugated polymers with narrow bandgaps remains a big challenge for achieving high-performance near-infrared (NIR) phototransistors. Herein, we report a novel D–A conjugated polymer (denoted as TBOPV-DT) based on a thiophene-fused benzodifurandione-based oligo(p-phenylenevinylene) (TBOPV) acceptor in conjugation with a 3,3′-dialkoxy-2,2′-dithiophene (DT) donor. Benefiting from the alkoxylation of the donor units, the TBOPV-DT conjugated polymer exhibits broad second NIR absorption and a narrow bandgap of 0.65 eV. When being used as the channel material in field-effect transistors, the TBOPV-DT conjugated polymer shows p-type semiconducting behavior with a hole mobility of 0.16 cm2 V–1 s–1. Besides, the resulting single-component polymer phototransistor displays ultrahigh sensitivity to a broad range of wavelengths (850–1450 nm) and a record-high photoresponsivity of 1.9 × 105 A W–1. Moreover, the fast rise and decay response times of 53 and 317 ms, respectively, are comparable to those of state-of-the-art two-dimensional materials. This work sheds light on designing new narrow-bandgap D–A conjugated polymers with molecular precision and paves the way for the development of future high-performance optoelectronics