Organic optoelectronics calls for materials combining bright luminescence and efficient charge transport. The former is readily achieved in isolated molecules, while the latter requires strong molecular aggregation, which usually quenches luminescence. This hurdle is generally resolved by doping the host material with highly luminescent molecules collecting the excitation energy from the host. Here, a novel concept of molecular self-doping is introduced in which a higher luminescent dopant emerges as a minute-amount byproduct during the host material synthesis. As a one-stage process, self-doping is more advantageous than widely used external doping. The concept is proved on thiophene-phenylene cooligomers (TPCO) consisting of four (host) and six (dopant) conjugated rings. It is shown that <1% self-doping doubles the photoluminescence in the TPCO single crystals, while not affecting much their charge transport properties. The Monte-Carlo modeling of photoluminescence dynamics reveals that host-dopant energy transfer is controlled by both excitonic transport in the host and host-dopant Förster resonant energy transfer. The self-doping concept is further broadened to a variety of conjugated oligomers synthesized via Suzuki, Kumada, and Stille crosscoupling reactions. It is concluded that self-doping combined with improved excitonic transport and host-dopant energy transfer is a promising route to highly luminescent semiconducting organic single crystals for optoelectronics.

Two main factors governing the effect of terminal substituents on the properties of thiophene–phenylene co-oligomers are revealed.

A combination of low limit of detection, low power consumption, and portability makes organic field-effect transistor (OFET) chemical sensors promising for various applications in the areas of industrial safety control, food spoilage detection, and medical diagnostics. However, the OFET sensors typically lack air stability and restoration capability at room temperature. Here, we report on a new design of highly sensitive gas sensors based on Langmuir−Schaefer monolayer organic field-effect transistors (LS OFETs) prepared from organosilicon derivative ofThe devices fabricated are able to operate in air and allow an ultrafast detection of different analytes at low concentrations down to tens of parts per billion. The sensors are reusable and can be utilized in real-time air-quality monitoring systems. We show that a direct current response of the LS OFET can be split into the alteration of various transistor parameters, responsible for the interactions with different toxic gases. The sensor response acquiring approach developed allows distinguishing two different gases, H 2 S and NH 3 , with a single sensing device. The results reported open new perspectives for the OFET-based gas-sensing technology and pave the way for easy detection of the other types of gases, enabling the development of complex air analysis systems based on a single sensor.

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Modern solid-state gas sensors approaching ppb-level limit of detection open new perspectives for process control, environmental monitoring and exhaled breath analysis. Organic field-effect transistors (OFETs) are especially promising for gas sensing due to their outstanding sensitivities, low cost and small power consumption. However, they suffer of poor selectivity, requiring development of cross-selective arrays to distinguish analytes, and environmental instability, especially in humid air. Here we present the first fully integrated OFET-based electronic nose with the whole sensor array located on a single substrate. It features down to 30 ppb limit of detection provided by monolayer thick active layers and operates in air with up to 95% relative humidity. By means of principal component analysis, it is able to discriminate toxic air pollutants and monitor meat product freshness. The approach presented paves the way for developing affordable air sensing networks for the Internet of Things.