2020, Sahabudeen, Hafeesudeen, Qi, Haoyuan, Ballabio, Marco, Položij, Miroslav, Olthof, Selina, Shivhare, Rishi, Jing, Yu, Park, SangWook, Liu, Kejun, Zhang, Tao, Ma, Ji, Rellinghaus, Bernd, Mannsfeld, Stefan, Heine, Thomas, Bonn, Mischa, Cánovas, Enrique, Zheng, Zhikun, Kaiser, Ute, Dong, Renhao, Feng, Xinliang

Single-layer and multi-layer 2D polyimine films have been achieved through interfacial synthesis methods. However, it remains a great challenge to achieve the maximum degree of crystallinity in the 2D polyimines, which largely limits the long-range transport properties. Here we employ a surfactant-monolayer-assisted interfacial synthesis (SMAIS) method for the successful preparation of porphyrin and triazine containing polyimine-based 2D polymer (PI-2DP) films with square and hexagonal lattices, respectively. The synthetic PI-2DP films are featured with polycrystalline multilayers with tunable thickness from 6 to 200 nm and large crystalline domains (100–150 nm in size). Intrigued by high crystallinity and the presence of electroactive porphyrin moieties, the optoelectronic properties of PI-2DP are investigated by time-resolved terahertz spectroscopy. Typically, the porphyrin-based PI-2DP 1 film exhibits a p-type semiconductor behavior with a band gap of 1.38 eV and hole mobility as high as 0.01 cm2 V−1 s−1, superior to the previously reported polyimine based materials. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

2021, Shi, Huanhuan, Fu, Shuai, Liu, Yannan, Neumann, Christof, Wang, Mingchao, Dong, Haiyun, Kot, Piotr, Bonn, Mischa, Wang, Hai I., Turchanin, Andrey, Schmidt, Oliver G., Shaygan Nia, Ali, Yang, Sheng, Feng, Xinliang

Overcoming the intrinsic instability and preserving unique electronic properties are key challenges for the practical applications of black phosphorus (BP) under ambient conditions. Here, it is demonstrated that molecular heterostructures of BP and hexaazatriphenylene derivatives (BP/HATs) enable improved environmental stability and charge transport properties. The strong interfacial coupling and charge transfer between the HATs and the BP lattice decrease the surface electron density and protect BP sheets from oxidation, resulting in an excellent ambient lifetime of up to 21 d. Importantly, HATs increase the charge scattering time of BP, contributing to an improved carrier mobility of 97 cm2 V-1 s-1 , almost three times of the pristine BP films, based on noninvasive THz spectroscopic studies. The film mobility is an order of magnitude larger than previously reported values in exfoliated 2D materials. The strategy opens up new avenues for versatile applications of BP sheets and provides an effective method for tuning the physicochemical properties of other air-sensitive 2D semiconductors.