Frit, or powdered glass, has traditionally been used for sealing and coating electronic parts and in plasma display panels. Recently, it has been attracting a lot of attention as an electrode binder in crystalline silicon solar cells*1, making them more efficient at generating power.
To lower the softening point of glass, lead is usually added to make the frit*2. However, AGC Group is endeavouring to make frit with alkali, tin, and phosphoric acid in order to discontinue the use of lead.

Powder Glass		Electrodes used in crystalline silicon solar cells

*1 Lead-free frit is used as an electrode binder in crystalline silicon solar cells.

*2 The melting point of glass can be lowered by adding lead, hence lead has been used in artistic glass since ancient times. Glass is a stable material and therefore the risk of lead contained in glass being released into the environment is extremely low. However RoHS directive restricts the use of such as lead in Europe and lead content is being reduced or phased out, particularly in glass used in electrical products.