“Engineers at Pennsylvania State University have demonstrated a practical way to integrate gallium nitride LEDs and their power supply circuits onto the same chip using industry-standard manufacturing processes.” The results promise a cheap lighting chip that runs directly from the AC electricity supplied by a wall outlet (110-120V AC).
Researchers say that this makes making LED lights cheaper, because according to them as much as 60 percent of the cost of an LED bulb comes from the driver electronics. I think this number might be old news from era of complicated isolating low voltage supplies.
Nowadays LED bulb makers from China have made the power non-isolating supplies for LED bulbs very cheap (easiest one cheap chip or capacitor). So many of the ideas used here (series of LEDs matching mains voltage and simple current limiting) are already used already on cheap mains powered COB LED modules built with just few components. Like this: