The record silicon solar cell light conversion efficiencies were reached by replacing doped silicon with passivated amorphous silicon heterojunctions. The next step of the silicon solar cells’ further development towards the theoretical efficiency limits and less costly fabrication techniques is using the dopant-free extreme work-function materials as substitutes for doped a-Si:H p-type or n-type contacts to avoid silicon doping-related recombination and toxic gas precursors used for a-Si:H synthesis.
Graphene has some advantages over the dopant-free extreme work-function materials because graphene can be used both as a transparent conductor and electric field-inducing material.
Radial junction solar cell architecture is prospective for further developing the graphene/Si solar cells. It can provide a considerable reflectance reduction and solve the tradeoff between better carrier selectivity/contact passivation (thicker layers) and better carrier extraction (thinner layers) by decoupling carriers’ collection from the light absorption. For such solar cells, transferred graphene should be replaced by directly grown to ensure steady cover of the complex solar cell surface and avoid unwanted adsorbates and wrinkles.
Surface recombination should be reduced along with reduced reflectivity to enhance the graphene-based solar cell light conversion efficiency. It is necessary to insert an appropriate dielectric interlayer. Hexagonal boron nitride (h-BN) ensures appropriate silicon surface passivation and epitaxial growth of the larger size’s lower defects density graphene flakes. However, most graphene synthesis on h-BN experiments was done on transferred boron nitride or boron nitride grown on Cu foil. Direct boron nitride synthesis on silicon and direct graphene synthesis on boron nitride are necessary. Therefore, the proposed research aims to enhance the graphene/silicon solar cell efficiency by using the radial cell architecture of the graphene-coated micropillars and directly synthesized passivating BN interlayer.
In such a way, the proposed research aims to enhance the graphene/silicon solar cell efficiency by using the radial cell architecture of the graphene-coated micropillars and directly synthesized passivating BN interlayer. The project objectives are:
BN synthesis of the flat Si(100) surface and study of their composition, structure and morphology.
Synthesis of the graphene on BN covered flat Si(100) surface and study of their structure and morphology.
Synthesis of the BN and graphene/BN stack on Si pillars and study of their structure and morphoplogy.
Fabrication of the graphene/BN/Si solar cells and study of their electrical and photovoltaic properties.
Project funding:
Projects funded by the Research Council of Lithuania (RCL), Projects carried out by researchers’ teams
Project results:
The project began on June 1, 2022.
Period of project implementation: 2022-06-01 - 2025-03-31
Project coordinator: Kaunas University of Technology
