A salient characteristic of solar cells is their ability to subject photo-generated electrons and holes to pathways of asymmetrical conductivity—‘assisting’ them towards their respective contacts. All commercially available crystalline silicon (c-Si) solar cells achieve this by making use of doping in either near-surface regions or overlying silicon-based films. Despite being commonplace, this approach is hindered by several optoelectronic losses and technological limitations specific to doped silicon. A progressive approach to circumvent these issues involves the replacement of doped-silicon contacts with alternative materials which can also form ‘carrier- selective’ interfaces on c-Si. Here we successfully develop and implement dopant-free electron and hole carrier- selective heterocontacts using alkali metal fluorides and metal oxides, resulting in power conversion efficiencies of 20%.
Project end date: 02/19/19