A Simple Physical Model for Three-Terminal Tandem Cell Operation

Pauls Stradins, Adele Tamboli, Emily Warren, Michael Rienaecker, Robby Peibst

Research output: Contribution to conferencePaperpeer-review

5 Scopus Citations


We present a simple physical model that explains the device operation of a three-terminal (3T) IBC Si bottom cell platform that enables an efficient 3T tandem. If the IBC cell has two p-n junctions and one high-low junction (bipolar transistor), the two p-n junctions strongly interact via minority carrier diffusion in the base. In a two-BSF junction and one p-n junction IBC platform (single emitter), the BSF terminals interact via ohmic majority carrier current in the base. This interaction creates wide "generating" power islands in the 2D current J1J2 plane. The area and shape of these islands are determined by dissipative losses in the wafer base and in the cell contacts. Both positive and negative terminal currents are allowed for 3T operation, thus enabling both the top and bottom cells to operate at their full light currents. This opens new possibilities for 3T use in modules.

Original languageAmerican English
Number of pages3
StatePublished - Jun 2019
Event46th IEEE Photovoltaic Specialists Conference, PVSC 2019 - Chicago, United States
Duration: 16 Jun 201921 Jun 2019


Conference46th IEEE Photovoltaic Specialists Conference, PVSC 2019
Country/TerritoryUnited States

Bibliographical note

Publisher Copyright:
© 2019 IEEE.

NREL Publication Number

  • NREL/CP-5900-73142


  • bipolar transistor
  • photovoltaic cells
  • silicon


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