This paper reports a facile and scalable process to achieve high performance red perovskite light-emitting diodes (LEDs) by introducing inorganic Cs into multiple quantum well (MQW) perovskites. The MQW structure facilitates the formation of cubic CsPbI perovskites at low temperature, enabling the Cs-based QWs to provide pure and stable red electroluminescence. The versatile synthesis of MQW perovskites provides freedom to control the crystallinity and morphology of the emission layer. It is demonstrated that the inclusion of chloride can further improve the crystallization and consequently the optical properties of the Cs-based MQW perovskites, inducing a low turn-on voltage of 2.0 V, a maximum external quantum efficiency of 3.7%, a luminance of ≈440 cd m at 4.0 V. These results suggest that the Cs-based MQW LED is among the best performing red perovskite LEDs. Moreover, the LED device demonstrates a record lifetime of over 5 h under a constant current density of 10 mA cm . This work suggests that the MQW perovskites is a promising platform for achieving high performance visible-range electroluminescence emission through high-throughput processing methods, which is attractive for low-cost lighting and display applications.

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Ferroelectric organic field-effect transistors (Fe-OFETs) have been attractive for a variety of non-volatile memory device applications. One of the critical issues of Fe-OFETs is the improvement of carrier mobility in semiconducting channels. In this article, we propose a novel interfacial buffering method that inserts an ultrathin poly(methyl methacrylate) (PMMA) between ferroelectric polymer and organic semiconductor layers. A high field-effect mobility (μFET) up to 4.6 cm2 V−1 s−1 is obtained. Subsequently, the programming process in our Fe-OFETs is mainly dominated by the switching between two ferroelectric polarizations rather than by the mobility-determined charge accumulation at the channel. Thus, the “reading” and “programming” speeds are significantly improved. Investigations show that the polarization fluctuation at semiconductor/insulator interfaces, which affect the charge transport in conducting channels, can be suppressed effectively using our method.