We investigate the influence of the barrier type and the absorber doping on the open circuit voltage of liquid phase crystallized silicon solar cells on glass. It was found that the use of n type instead of p type substrates is the major reason for the recently reported boost of the open circuit voltage Voc up to values of 656mV which is by far exceeding the previously reported Voc values of crystalline silicon solar cells on glass. Despite the high doping, locally an internal quantum efficiency of 90 can be achieved. Therewith, efficiencies of 16 and up should be possible