Titanium dioxide/silicon hole-blocking selective contact to enable double-heterojunction crystalline silicon-based solar cell

Ken A. Nagamatsu, Sushobhan Avasthi, Girija Sahasrabudhe, Gabriel Man, Janam Jhaveri, Alexander H. Berg, Jeffrey Schwartz, Antoine Kahn, Sigurd Wagner, James Christopher Sturm

Research output: Contribution to journalArticle

79 Scopus citations

Abstract

In this work, we use an electron-selective titanium dioxide (TiO2) heterojunction contact to silicon to block minority carrier holes in the silicon from recombining at the cathode contact of a silicon-based photovoltaic device. We present four pieces of evidence demonstrating the beneficial effect of adding the TiO2 hole-blocking layer: reduced dark current, increased open circuit voltage (VOC), increased quantum efficiency at longer wavelengths, and increased stored minority carrier charge under forward bias. The importance of a low rate of recombination of minority carriers at the Si/TiO2 interface for effective blocking of minority carriers is quantitatively described. The anode is made of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) heterojunction to silicon which forms a hole selective contact, so that the entire device is made at a maximum temperature of 100?°C, with no doping gradients or junctions in the silicon. A low rate of recombination of minority carriers at the Si/TiO2 interface is crucial for effective blocking of minority carriers. Such a pair of complementary carrier-selective heterojunctions offers a path towards high-efficiency silicon solar cells using relatively simple and near-room temperature fabrication techniques.

Original languageEnglish (US)
Article number123906
JournalApplied Physics Letters
Volume106
Issue number12
DOIs
StatePublished - Mar 23 2015

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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