Patent ID: 8975509
Filing Date: 2015-03-10
Classification: H01L,Y02E

Abstract:
1. A multijunction energy-converting device comprising: (a) first and second electrodes, (b) a photovoltaic stack in electrical contact with said first and second electrodes and comprising a plurality of photovoltaic junctions, each said photovoltaic junction comprising an electron-accepting semiconductor layer and a light-absorbing semiconductor layer having a substantially larger work function than said electron-accepting semiconductor layer, said plurality of photovoltaic junctions comprising a first photovoltaic junction and a second photovoltaic junction that are separated by (c) a recombination region comprising a transparent and conductive hole-accepting layer in ohmic contact with said light-absorbing semiconductor layer of said first photovoltaic junction, a transparent and conductive electron-accepting layer in ohmic contact with said electron-accepting semiconductor layer of said second photovoltaic junction, and an additional transparent and conductive interlayer disposed between, and having a work function between, said transparent and conductive hole-accepting layer in ohmic contact with said light-absorbing semiconductor layer of said first photovoltaic junction and said transparent and conductive electron-accepting layer in ohmic contact with said electron-accepting semiconductor layer of said second photovoltaic junction; said recombination region forming a gradient in work function from said transparent and conductive hole-accepting layer in ohmic contact with said light-absorbing semiconductor layer of said first photovoltaic junction to said transparent and conductive electron-accepting layer in ohmic contact with said electron-accepting semiconductor layer of said second photovoltaic junction, and having a thickness within one order of magnitude of the sum of the Debye lengths of all layers of said recombination region.