Effective laser sealing enabled by glass thick films containing carbon black/carbon nanotubes

An effective way of providing complete sealing of glass using an 810 nm diode laser was investigated for longer lifetime of glass panel-based devices. Small amounts (<5 wt%) of laser-absorbing materials such as carbon black (CB) or carbon nanotubes (CNT) were added to a bismuth zinc borate glass paste for instantaneous adhesion between glass substrates without interfacial cracks or severe pores. A higher laser power was required for a lower content of carbon for the laser-assisted sealing of glass. As optimal compositions, the addition of 1.0 wt% CB or 0.5 wt% CNT led to complete densification of glass with higher optical transmittance. Higher absorption coefficients calculated in the CNT case, e.g., ∼536.4 cm^-1 for the 0.5 wt% CNT sample compared to ∼277.6 cm^-1 for the 0.5 wt% CB sample, are believed to be responsible for the effective sealing even with a lower content of CNT.