In this article, EPCB aims to build a wider understanding of the detrimental effect of chemicals on LED PCB products, particularly LED chips.
You can found a phosphor coating on most of the LED chips we use today which determines the color temperature of the chip as well as adding some level of protection to some degree.
However, it has been found that certain chemicals and moisture can penetrate through the phosphor coating, and start degradation and oxidation of the Ag plating inside the chip package. It’s terrible, because the Ag discolors when this happens. Besides, chemicals and moisture also can cause a phosphor discolor condition which initially effects the CCT output of the chip. Even worse, they can damage the chip itself, leading to premature failures and significantly shorten its lifetime.
As to the oxidization, once it starts, the heat generated in the LED chip will exacerbate the process and the degradation becomes evident and worsens over a very short period of time.