2021 Nature (IF 49.962): Breakthrough development of n-doping of organic semiconductors bottleneck

　　In November2021, Nature (IF 49.962) published a study. N-doping of organic semiconductors is important for the development of light-emitting diodes, solar cells, thin-film transistors, and thermoelectric devices. It is also a key process for studying charge transport in organic semiconductors and improving certain (opto) electronic devices. Although there have been many studies on solution-based n-doping, only a few air-stable n-dopants have been developed. Among them, organic hydrides, dimers of organic radicals, and mono-/multi-valent anions have been most prominent. Effective molecular n-dopants should simultaneously exhibit high reducing power and air stability for wide applicability. The concept of using precursor molecular dopants to catalyze organic semiconductors for n-type doping is presented here, and transition metals (TMs) are further used to solve the bottleneck of n-type molecular doping.

　　The article mentioned that TM-catalyzed C-H and C-C bond cleavage reactions are widely used in organic synthesis. The most common TM belongs to group 8-11 elements, and its catalyst exists in the form of nanoparticles and organometallic complexes. Nanoparticle size, supporting material and the chemical structure of the complex greatly affect the catalytic activities. Here, authors incorporate transition metals (for example: Pt, Au, Pd) as vapor-deposited nanoparticles or solution-processable organometallic complexes (for example: Pd₂(dba)₃) into the catalytic reaction to observe the performance.

　　The use of TM catalyst promotes the reactivity of the dopant precursor by facilitating C–H bond cleavage, as evaluated by DFT calculations, and provides the same reaction product as the uncatalyzed reaction evaluated in the experiment. Enlitech’s Solar Simulator was used in this study to assist in the measurement of experimental data. It was found that η can be increased very well in a shorter doping time and high electrical conductivity (above 100 S cm^-1). It has also been proved to be suitable for organic thermoelectric, thin film transistor and perovskite solar cell devices that require high charge carrier density and/or high efficiency electron injection/transport. This methodology has technical significance for improving semiconductor devices and provides a broad space for exploration in the ternary systems composed of semiconductors, molecular dopants, and catalysts. Open up a new path for n-doping research and applications.

　　Enlitech’s solar simulator complies with international standards. With KA-6000 software, it provides a short-term monitoring of time changes to prove the stability of the perovskite solar cell!