Spectrolab has achieved a record 36% 5J direct bonded cell, measured under an AM0 space spectrum. The increase in efficiency over previous high performance 5J cells was achieved via voltage improvements to subcell 2 and 4 of the multijunction stack. Spectrolab has also successfully grown components necessary to implement a 6J direct bonded cell with an efficiency target of 38%. In particular the bottom 3J cells have been grown with bandgaps near the target values and an average voltage bandgap offset of 0.36 V.