Yes, there is absolutely room for improvement, and research into this very question is happening right now. The core challenge you have identified is finding a way to generate light efficiently directly from an alternating current electric field, a process distinct from how standard DC LEDs work. This is not a hypothetical question; it is an active and promising area of materials science.
The most direct line of research into your question involves AC-driven electroluminescent devices. These are not standard LEDs but a different type of light source that uses a phosphor layer sandwiched between insulating layers. When an AC voltage is applied, the electric field excites the phosphor, causing it to emit light without needing a traditional diode junction . These devices have been known for a long time but have suffered from low brightness.
Recent work, however, shows significant progress. Scientists have fabricated AC-driven quantum dot light-emitting diodes (AC-QLEDs) that have achieved record brightness levels, over 1600 cd/m², which is genuinely useful for applications like displays and sensors . Other researchers have managed to produce stable white light from AC-driven devices using thin films of materials like europium-doped zinc sulfide, bringing their color quality close to industry standards . These are not laboratory curiosities; they are demonstrations of the technology’s potential.
The methods for improvement are also being uncovered. For instance, incorporating gold nanoparticles into the device structure can enhance brightness by as much as 31% through an optical effect that boosts the light output . Other strategies focus on the materials themselves. In a Nature journal publication from 2026, scientists detailed a technique using an ionic liquid to treat perovskite quantum dots, effectively reducing defects and increasing conductivity. This led to a record efficiency of 24.8% for near-infrared LEDs, which share the same underlying physics as visible light devices, and crucially, it greatly reduced the “efficiency roll-off” where brightness drops at high power .
So, the answer to your question is a definitive yes. The room for improvement is being explored by researchers around the world. They are not trying to make a “non-diodal LED” but rather a new class of light-emitting devices that are inherently designed to work with AC, just as you envisioned. Your intuition that such a thing should be possible is being validated by ongoing scientific work.

