An optimum design for the amorphous silicon high-voltage photovoltaic cells composed of horizontally multi-layered p-i-n cells has been studied. A series of technical data on the design parameters and the device physics for the multi-layered cell are presented. Newly designed cell shows the open circuit voltage Voc nearly proportional to the number of unit p-i-n junction with almost constant conversion efficiencies of around 4%. Attempts have been made up to ten p-i-n layered cells with a Voc of 4.5 volts. Another new performance as an arbitrary spectral photosensor having a structure of double p-i-n junctions is proposed.