After gaining sufficient kinetic energy, the electrons impact the luminescent centers, thereby leading to the generation of excitons and light emission 15, 16, 17, 18. The device functions as a capacitor and under the driving of a high AC electric field, the electrons, internally generated from the trapped sites, can tunnel into the emissive layer. The use of insulating layers blocks the injection of external charge carriers and thus there is no DC current flowing through the devices. Typical AC-EL devices consist of a phosphor emissive layer sandwiched between two insulating layers (Supplementary Fig. Therefore, it is highly desirable to develop LEDs or electroluminescence (EL) devices that can be directly driven by household 110 V/220 V at 50 Hz/60 Hz without complicated back-end electronics. As a result, introducing the AC-DC converters and DC drivers not only incurs additional costs (accounting for approximately 17% of the entire LED lamp cost) 14 but also increases power consumption and reduces the robustness of LED lamps. The reliability of driver circuits can impact the durability of LED lamps. In addition, to tune the brightness of LEDs, a dedicated driver circuit should be used to regulate the DC power and supply the ideal current to the LEDs (Supplementary Fig.

Although most AC-DC converters can achieve conversion efficiencies of over 90% 7, 8, 9, 10, 11, energy losses remain during the conversion process. Typical AC-DC converters consist of a transformer to step down the mains voltage and a rectification circuit to rectify the AC input (Supplementary Fig.

Therefore, when LEDs are driven by household electricity, an additional AC-DC converter is required as an intermediary to convert high-voltage AC into low-voltage DC. Moreover, the global electricity supply is dominated by high-voltage alternating current (AC), which cannot be directly used by numerous household appliances like LED lamps. Due to the unidirectional and continuous charge injection, the charges as well as the Joule heat can accumulate within the devices, thereby reducing the operational stability of LEDs 5, 6.

As a semiconductor pn diode, LED can only be operated under the driving of a low-voltage direct current (DC) source. Light-emitting diodes (LEDs) have become the mainstream lighting technology due to their advantages of high efficiency, exceptional longevity, solid state, and environmental safety, which fulfills the global demand for energy efficiency and environmental sustainability 1, 2, 3, 4. The developed plug-and-play quantum-dot LED panel could enable the production of cost-effective, compact, efficient, and stable solid-state light sources that can be directly powered by household alternating current electricity. Under 220 V/50 Hz driving, the red plug-and-play panel demonstrates a power efficiency of 15.70 lm W −1 and a tunable brightness of up to 25,834 cd m −2. Furthermore, by connecting multiple tandem devices in series, the panel can be directly driven by household alternating current electricity without the need for complicated back-end circuits. Here, by using a transparent and conductive indium-zinc-oxide as an intermediate electrode, we develop a tandem quantum-dot LED that can be operated at both negative and positive alternating current cycles with an external quantum efficiency of 20.09% and 21.15%, respectively. Thus, a driver circuit is required, which increases the complexity and cost. As an intrinsically direct current device, quantum-dot LED cannot be directly driven by household alternating current electricity.

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