Bolb Inc. Develops Transparent Hole-Supplying Layer for UVC LEDs, Tripling Output Without Voltage Penalty

Startup firm Bolb Inc. of Livermore, California USA, announced a new line of ultraviolet c-band LEDs. The new UVC LEDs boast record single-chip performance for universal disinfection. According to the company, UVC LEDs made by Bolb Inc. have achieved 12.2% external quantum efficiency (EQE), a record for UVC LEDs. Bolb Inc. contends that companies will choose its UVC LED technology for medical devices and consumer appliances in which chemical-free, residue-free and non-toxic disinfection is desired.

Bolb Inc. -- UVC LED achieves triple output with UVC-transparent hole-suplying layer, without reducing voltage-current performance.

Bolb Inc. — UVC LED achieves triple output with UVC-transparent hole-supplying layer, without reducing voltage-current performance.

The firm points out that the physical inactivation method that UVC LEDs enable works equally well against common and emerging pathogens, even those with multi-drug resistance.

Bolb Inc. says that for the past two decades, researchers have been confounded by the hole-supplying layer in a UVC LED that unfortunately reduces efficiency by absorbing light. However, the company says that attempts at removing this narrow bandgap layer always lead to a considerably degraded current-voltage performance, which results in higher heat generation and shorter device lifetimes.

UVC-Transparent Hole-Supplying Layer Triples Output Without Voltage Tradeoff

Bolb Inc. says its new LEDs featuring the UVC-transparent hole-supplying layer do not experience a voltage tradeoff. Because they do not suffer from this decline in current-voltage performance, the company says its packaged LEDs simultaneously achieve 12.2% EQE and 9.5% wall-plug efficiency (WPE).

For example, a single 0.5×0.25 mm production LED with an optimized disinfection wavelength of 265~275 nm driven at 20mA forward current can achieve 10~11 mW of UVC power, while maintaining a 5.8V forward voltage. The company claims that such single-chip performance is 3-5 times that of the competitors’ offerings at similar wavelengths. Furthermore, the company asserts that arrays of such emitters or a single emitter designed for higher drive currents can attain unprecedented performance.

Moreover, the company says that its breakthrough paves the way for UVC LEDs to achieve efficiencies approaching those of visible LEDs within the next few years, and the company says its achievement also enables wide-ranging applications in hospitals, packaging plants, restaurants, agriculture, and homes.

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